So we have a bit of an experimental camera set up today. So I might be bouncing back and forth in and out of your frame and sometimes looking at you and sometimes looking to my side where my computer is. I'm not used to television stardom yet. So forgive us for a little while as we get used to our newfound fame. So for those of you who joined us last week, you may have seen a short talk I gave on model making and models called the composite model. This talk in some ways is a bit of a spin-off of that one in that we'll be taking photographs of models and talking almost exclusively about photographs of models. But also that the intention is that we, hang on just a second. The intention is that we extend this notion of making, making by hand, making by machine, the sort of overlap of the digital and the analog into the realm of photography. So photography at G-SOP among student work sort of quasi professional work is a pretty big deal only because it's become more in the currency of representation I'd say in the last sort of maybe five years that I'd seen it previously. Now this has to do with a number of things but the thing that I'm the most interested in is why and how photography occurs in the shop. So on a practical level, the shop is one of the major spaces at sort of the institution at G-SOP that has a sort of infrastructure and control over light and sort of rotating open space that allows us to really take photography seriously. But it also makes the most sense because people's skills as makers and fabricators here translate very directly to the world of photography. Photography is even though it's a two-dimensional sort of output at the end of the day, it is a very physical process. It involves actually making things, physical things. It involves the manipulation of physical objects and light which technically you might argue as a physical object. Manipulation of light on a physical object to sort of bring them form. So everything happens by hand and in 3D and is often sort of heuristic in the way that you put it together. There are rules of thumb that you can follow that we're gonna go over a little bit today. But at the end of the day, it's kind of a scrappy operation that you can sort of throw together and get really, really good results out of. So also today, I want to, I'm gonna be demonstrating on this fancy, shamancy setup with all of these lights and cameras surrounding me because this is the photo studio equipment that we have here. All of these practices and principles are extendable to your bedroom or dining room table. These are all things today and I hope that you can take that away from this. Practices that you can achieve with very little money equipment means usually just your phone and a couple lights at home. And I'm gonna be calling out some of the moments where what we're doing has an obvious analog to what you might be doing at home, what you might be able to do at home. So I'm gonna go over three topics today. I'm gonna talk about a little bit about photography as representation in model making. Again, I'm not the local export on the historical discourse of photography and architecture. I've paid really close attention to it throughout my own career as an architect and maker. What I'm probably am the local expert on is the sort of witnessing of student work, the sexually student model making and the ways that they employ photography to extend the life of their models. It's also become instrumental in the deliverables for the courses I teach here. I teach courses that are mostly shop oriented, sort of focused on tools, techniques, materials and methods. But all of the deliverables that I sort of asked my students for at the end of the semester has shifted almost entirely to photography because I found that it actually allows people to get deeper into the making of things, sort of pay attention to the detailing and the big picture of things and then really think about how they are being staged and presented. So the second thing I wanna talk about today is actual optics, just the technical facets of photography for those who haven't sort of gotten into it at that level. You may own a point and shoot camera. You may just use your phone as a camera like 97% of people do these days. You may own a DSLR or a mirrorless camera and have gotten into the settings a little bit and you might know everything about how depth of field relates to aperture and focal length. But I'm gonna give a sort of an overview of all of those things today. So you can think about how it applies to taking pictures of close up objects and getting the sort of focus and types of photos that you want. And then the third thing I'm gonna go through today is actual sort of a rough overview of photography principles. So as it comes to staging models and taking photographs of models. So again, I am not the trained expert in photography. I just de facto do it a lot on my own and with students. And what I'm gonna be showing you today is the things that I've learned from them and they've learned from me back and forth. Okay, so I'm gonna share my screen and ideally this camera that we have on the scene will be on all the time. So if you wanna switch back and forth between what I'm showing on my shared screen which will mostly be the software that we're using today and the camera of the scene, you can toggle back and forth between them in Zoom. Okay, when we talk about photography design and representing a model or an architecture via photography, what are we really talking about? An important concept to wrap your head around is the subject of a photograph. So what is the subject? In the context of photography like this, it has a built environment and potentially a scale figures in it. The subject has a double meaning between the sort of visual focus of the scene and the thematic focus of the scene. So there is a compositional aspect to it. What is actually highlighted in your photo? What is your eye drawn to? And what is the story that you're telling through the photo? What's the thematic focus? How are you arranging the scene, lighting the scene, documenting the scene, such that a particular story pops out? I don't know what the story being told in the scene is but I love it. Is the subject of your photography the object? For example, as we might think of in product photography. Product photography is almost exclusively photographs of an object as detailed and well-lit as possible. But how can a photograph of an object, a singular object in a sort of a blank field tell a story as well? Is the subject craft or construction? Is the subject scale? Is the subject a depiction of an environment or the telling of a story? So photographers like to say that light gives form to subjects, right? Photographers, painters. That light is your actual medium, that you're, it's the thing that's under your control. After things are set in place, they're set in place. You have sort of limited ability to move things around in three dimensions that correspond to the frame of your camera. But it's really light that gives structure and guidance to everything that you see in the picture. So I include a Rembrandt in here just to bring up the idea of what photographers call Rembrandt light. This is a good term to use. One, if you wanna make really sharp-looking portraits. But also if you wanna wrap your head around the idea of a light that is both revealing and sort of new on at the same time. So really what Rembrandt light means technically in photography is when you see the small triangle of light on somebody's cheek that turned away from the main aim of the light. This sort of depiction of faces is a classic in old masters paintings. But it's also used contemporarily as a sort of a standard photography, a standard type of photograph. It's when you wanna see the whole in the entire form of someone's face, but also have very sort of drastic shaping and contrast to it. But these notions, so I'll let you look through. You can Google the top 10 forms of photography or portraiture light types that are used. But I would argue that each one of them has an extension into both architecture and architecture models. Architecture models are probably closer to portraits than they are to full-scale architectures in a lot of ways. So when you use light in a photograph, especially a model photograph, I would challenge you to answer the question, you know, how are you using it? Are it's controlled in studio settings as much as possible?  You know, architectural photographers hunt for the perfect time of day, the perfect time of year, the perfect season to get just the right photograph. Architectural photographers will fly all the way around the world on one sort of given week to get the right light. But you have control over that in the studio. So how are you using it? Are you trying to minimize shadows as in what some product photography does? Are you trying to use them to reveal form? Are you using them for composition? So I wanna go through just a couple of excellent precedents of architectural sort of model photography. A lot of these come from the photographer, James Ewing, who has been a friend of GSAP for the last couple of years. He has, he's local, I guess you can say local in your Hudson Valley compared to Manhattan. But he's a locally based architectural photographer who has carved out a space especially in his work with models. And he has both taught courses at GSAP for the last couple of years and been involved in GSAP exhibitions at the Buell Center, the Arthur Ross Gallery, like this photograph and has also led student-based workshops on photography. So what you're seeing in these models are, these are models that were built for Kenneth Frampton's classes over, I don't actually know the period of time over which these were made, but they've been sort of beautiful museum quality archived objects of GSAP for a good long time now. And as sort of one, I wanna say last hurrah because I think they're still around, but as sort of a contemporary way to bring them out and give them a new focus, the exhibition folks here at GSAP curated this show called StageCraft where they unearthed these models and James Ewing and his assistant set them up in quasi-architecturally realistic scenarios and then photographed them. And then for the exhibition, the models were on display with his printed photographs behind them. The thing that, so the scale of these is all, this model is probably about two and a half or three feet. So like 30 to 36 inches on its long ends in total. Those, this is a Utzon building and you can see those, the thickness of the roof that you might see is probably about a quarter inch for scale, but what Ewing does sort of particularly well is kind of eliminate the idea of scale through his photographs. So they're taken not only to be maybe hyper real, but James shoots in a way that he tries to use the photograph straight out of the camera maximally. So in other words, that doesn't mean no Photoshop or no tweaking, but it means that the bulk of the work, the vast majority of the work, 95% of it is done in person and at the point of the camera. Lila has linked to that in the chat so you can see it. So he does this through really sophisticated control of light in the scene. His stagings are enormous. They'll take up half of a sprawling room with backdrops and camera and equipment and lights and projectors. So what you're seeing is probably a live projected image onto the background right there that is not Photoshopped in. Liberal use of smoke machines. He says he never forgets to bring a smoke machine to a shoot. Just so everyone knows at that link at the bottom, there's a significant number of images of the actual staging process. So you can get a sense of like what James looks like in the room where the projected image is. So you can see the direct correlation between the images you're seeing here and how they're produced. Thanks Lila. I think I have a couple of those, but that would be a great link to click so you can see the sort of behind the scenes. I have some behind the scenes and another exhibition that he did here that I'll show a little bit later. But the, I think the main takeaway that I would call out from James' process is how long it takes to get one shot, usually more than a day. So this shot that you're seeing right here was probably constructed over the course of a day and then probably only perfected the next day. It is a long nuanced and patient process of getting the light just right. But you can see the results are pretty incredible. So here you see, you kind of start to peel away the background a little bit and see what's going on. Another actual photographer who teaches in Europe that I would call out is Maxim Delbo. He teaches a studio, I wanna say in Brussels where the main challenge for his students in the course is to construct and render architectural physical models such that they can be photographed at very close scale to sort of replicate realistic scenes. And you can see that the results of this are nothing short of incredible just by, I mean, there's a clearly a well-executed craft in the details, but the techniques at their sort of route are simple. It is laid up layers of materials that you're familiar with, paper, museum board, wood liners. And then once you have the intricately constructed model, it actually doesn't take much to get sort of convincing light. So long as you know, the sort of tricks with photography to force this to look the correct scale. And that's one of the things that I'm gonna talk about a little later that I wanna call out from these. Sorry for the resolution of these. I think they're blowing up a little bit, but you get the idea. Another exhibition that's product was model photography. One of the products was model photography that I'll call out is the Never Built New York exhibition that happened three years ago. So this project has a longer explanation and a life of its own. But basically the Queens Museum in Flushing Meadows here in New York City has a one to 1200 scale model of the entirety of New York City. So that's all five boroughs in a space that is the size of a large gymnasium, I would say. Maybe like you could fit a solid two basketball court side to side. For those of you who haven't been there, once it's reopened, I highly suggest going. What the curators at the museum did and the authors of this exhibition, which are two writers from LA, is recreate or redraw or remodel Never Built projects. So sort of either failed or too aspirational or pulled the plug on for various reasons or speculative, fictional, futuristic aspirational projects that are often the sort of landmark projects of certain architects, but that never got built for one reason or another. They enlisted our help here at GSTAP and at the making studio to reconstruct these models. So we had a team of students working on it and throughout pretty much an entire summer and they dug through archival material and sort of forensically reconstructed for multiple images that often didn't completely sync up these buildings. And they were done in tricky material to photograph, which is clear-ish or frosted translucent material. So a combination of 3D prints and what you're seeing here, I think all of these models are frosted acrylic plastic, laser cut, but you can see the same techniques that work here, right? Everything is staged physically. There's no Photoshop. All of the cutouts in the background are physical cutouts. All of the lights in the background are actual physical lights that are being shown on the scene directly. There's a black and white sort of treatment that happens digitally to the pictures after they come out of the camera since they are digital pictures. But that is the only digital application to these photographs that happens. This one took a while to get right. But you can see that it works on the level of product photography almost as much as it works on the level of model or architecture photography. There's also active work from GSTAP courses every semester that is photography based, kind of like I mentioned earlier. One of the best examples being the course Transitional Geometry is which was designed by Trevor Watson, ran for four or five semesters before Trevor skipped town and handed the class over to me. I still refer to it as his class because it's kind of his legacy here, but it is ongoing. The class is about tiling and tessellating objects starting at a small scale and working up sort of architectural scales. So there's a craft and modeling exercise. There's a lot of technique in mold making. And what the course really does is it looks for analogs for the process of mold making to construction writ large. So that sort of overcuts, undercuts, all of like a mold making sounds like a straightforward process when you sort of listen to the two and a half minute YouTube tutorial. But it's actually a really comprehensive set of skills that takes more than a semester to teach but that is what this course is about. And the products are usually made in cast in cement but you can see the difference. The difference is in what I'm talking about between the images that treat the shadow like an object in the scene versus the photographs that try to eliminate shadows altogether. This is just a very simple difference between treatment of light in a scene but it comes up with a comprehensively different photograph at the end. One is sort of more of a floating ethereal object, photograph of the abstract. The other is way more sort of scaled implicit. It kind of has a human figure-ish aspect to it only accentuated by the shadow on the ground. It also gives it a sort of a realness that the other photos don't. Part of Trevor's course and I think something that's really important and extensible to the larger world of model making is taking photos of the process, taking photos of the tools that produce the process. We talk about documentation and the sort of importance of showing your work and the importance of preserving your workflow in one form or another which is usually in the form of quickly snapped smartphone pictures which can be good but I would hope that seeing these photos would convince a couple people to take the process of documentation midway as seriously as possible. There's also the idea of seeing the person in the scene. Now, these are often, I think these photographs started as a functional product of needing to balance these often precarious objects in the scene while somebody else is snapping photos but these photos with the hands, the human touch for both scale and sort of depiction of action and activity in the scene have become a central part of documenting this course as well. So some of the most powerful photos often show students' hands in them. Very fuzzy sweaters. This is something that you'll see across architecture. If you sort of pay not even really close attention to architectural photography in general, you'll see a set of practices that uses people in the scene not only for scale and depictions of occupation but for sort of storytelling purposes or for capturing action. Like for example, we probably all know if you pay attention to architecture for more than a week or two about the Dutch photographer Iwan Ban who's one of the main architectural photographers whose work has sort of come of age in the digital era, one of the most sort of prominent and important architectural photographers for at least the last 20 years. And his images are striking and digitally profound and complex and sort of rely on every single bit of cutting edge technology in terms of lenses and megapixels and the sort of micro contrast in life that you can get from modern equipment. But what he's known for and what is important about his photographs is the depiction of human subjects that are often a couple of them in the scene and they're not just randomly placed in the scene sitting or occupying, they're often sort of captured in motion. And this sort of motion blur of people in his photography is sort of a trademark of his that emerged as a result of the optics of what he was trying to do. Like his exposures probably take a quarter second to get the photograph he wants but he's simultaneously able to capture people in this sort of pseudo state of motion that tells a story way more than a static person in a scene would. So the things that I wanna call out here are the sort of uses of flatter light versus the uses of higher contrast, use of scale figures. I would encourage everybody to be as adventurous as possible with physical scale objects. It's a lot easier to arrange slightly less realistic, call them looking scale figures in your scene in terms of people, animals, plants, anything else than it is to convincingly Photoshop people into a scene and be grounded and permanent. You can go a long way with tiny little cutouts. I include these three images from Julia, a student in transitional geometries last year just to show sort of forcing of scale onto a system just by the imposition of different scaled objects. I think for this assignment, we asked for people to bring objects with three different scales so they could quickly force a visual reading of their model into those three different scales. And that's when you see that sort of particularly powerful at effect, what that can do. And these are all like five minute paper cutout furnitures, right? This is Louisa Furia, her model, I think she'd let me call it unruly, massive physical cement objects, definitely pushing the limit of, not only like the sort of physical construction of the course, but of the ability to capture something in photographs because her construction and tessellation of these objects quickly got bigger than any reasonable photo studio would be able to capture. So her photography project quickly became about getting into the scene and it's about her tiles, capacities to depict micro environments like this. And here, you're seeing the construction at a little bit of a bigger scale, but I thought it was really successful in those terms. This is Etta, another student from last year's, last fall's course. I thought, I bring hers in just because they were just particularly drastic with light, excellently done. And this is Wendy, she, I actually have her tiles here today, so Wendy, if you're watching, you're giving me permission to use them, immortalized her posterity. But just to show how this sort of forcing of scale upon objects can quickly produce different readings. I think one of the things I want to highlight as much as possible in sort of dramatic framing of this photography bit is that, just similar to the composite model idea, photography does not just need to be strictly a representation technique at the end of a process. That you should see photography as a tool, a crafting tool in the development of your design and as a sort of a tool of design thinking as much as it is a sort of hard codification and recastification of your project at the end. So that's what students in this course are encouraged to do is use their objects and models as working material and to develop the concept of what it actually is and does through the use of photography at different scales. This is Kate McNamara. I mean, she had this enormously complex, beautiful system of aperiodic tiling units that could form these sort of massive carpets with motifs that emerged and disappeared, depending on how you arranged them. But some of the most striking photographs she got were just three or four of them with scale figures in them. All right, I'm going to talk a little bit about lenses and photography and optics themselves. So if you are an amateur photographer, it may mean a couple of different things, but you probably know a little bit about the relationship of say focal length, which is how zoomed in your camera lenses to the depth of field that you got, which is that effect where you isolate something in focus, depending on where I am sitting in this 30 millimeter lenses view right now, I may or may not be entirely in focus, but that sort of process of capturing something in focus while you hold other things out of focus is the basis of a lot of photography, a lot of portrait photography, a lot of beautiful photojournalism on the New York Times Magazine. You know the pictures. Contemporary smartphone software actually has ways of sort of faking this, convincingly faking this sort of caught in focus idea, but I want to go over camera optics a little bit so you understand where that comes from and how you might employ that with or without the use of an actual SLR or mirrorless camera versus your smartphone. So to do that, I have this little tool constructed in Rhino. I'm counting on Lila to yell out if I'm not actually showing what I'm talking about, but this tool, what it does is it visualizes the focus range of any given lens based on the different parameters of the camera. So the first sort of parameter of a camera, if I have one I can hold up to my screen, is the lens itself and its focal length, which means how zoomed in it is. Your smartphone camera, and that sort of aspect of a photograph that you're probably used to at this point, that's sort of wide, it's able to capture a good amount of a scene or 12 people, I guess not these days, but some number of people standing together posing for a portrait with a little bit of the background in it, that would be considered a wide angle lens and all pretty much all smartphone cameras have an effective focal length that is about 25 to 27 millimeters if you were to see it in a sort of traditional 35 millimeter film camera. So if you haven't read about camera focal lengths and lenses before, just take that as a starting point. That sort of angle that you get out of a smartphone is on what is considered the wide angle lens. So in this tool, what I have is the ability to change the focal length of my camera. So this would be a 50 millimeter lens. So if your person is standing, let's say 10 feet away, a 50 millimeter lens will not capture the entire person, right? Likewise, what you could consider a zoom, this is considered a sort of just standard focal length. It's neither wide nor zoom. If you were to go up to 100 millimeters, you would be firmly into the territory of what's considered a zoom lens. So this is a lens that you would need to take photos from farther back to capture the entirety of subject. These are lenses that you would take pictures of wildlife if you couldn't get near them or sports action if you couldn't get onto the field. And you'll notice that the main property that changes at this focal length is that the depth of field gets very, very shallow. That is, it's not a linear association, but as you go up in sort of zoomed inness of your lens, so down goes the sort of standard depth of field that you capture. One way that you can control that depth of field is by changing the aperture on the camera. Now the aperture is without getting sort of into a long optical explanation is just the hole at the end of the camera that's caused by the aperture blades. So it's that sort of James Bond collapsing object that opens up the shutter. When you have your aperture all the way open, your biggest aperture that puts you at the skinniest or slice narrowest depth of field like you can see here. When you have your aperture closed pinhole tight, you get the broadest depth of field. So if I crank this aperture way up, you can see that my depth of field grows with it. The trade-off here is that when you make a very, very small sort of pinhole aperture, much less light gets into the camera for any given shutter length. So you have to adjust your shutter speed accordingly, often to be slower. And that's why we see photographs that are taken at night or like I'm gonna show now, photographs that are staged in a controlled light setting often do have longer exposures and very small apertures to catch things in focus. If you have Rhino and Grasshopper, you're free to download this tool and play around with it. I use it to get a sort of a rough preview of what I'm gonna be dealing with if I'm staging a photograph at different lengths of scene. But the one last thing I wanna say about this before I move on is that in model photography, we're often dealing with a focus distance that's quite small, right? That is to say that our subject, our models, are going to be very close to the camera. The other thing that happens with the depth of field, with respect to how close you are to the camera, is that it gets skinnier, it gets sort of more narrow slice as you get closer to the camera. You've probably seen this on your phone, that when you take a photograph of something that's a foot and a half away, it's much easier to get that sort of blurred background effect and much easier to catch something in focus in the foreground. That's because the optics of lenses work this way, the optics of light work this way. When you get closer, they get skinnier. So if I were to have this aperture at something quite wide, say like three is pretty wide, you can see that it's only giving a slice. You could not capture this person's nose and cheeks in focus at the same time from two feet away with 100 millimeter lens at aperture stop F 3.0. In model photography, we often work with wider lenses than that. Say this is a 40 millimeter lens or back to the sort of 27 standard smartphone picture size, you can see that the depth of field is still not all that deep. So if you're really getting close, how close can we go? If you're really getting close a foot away, even at a generous aperture, you're still only getting a skinny slice of the photograph. So this can be wonderful when you're trying to take a very beautiful sort of soft background portrait of somebody. But in model photography, it could become quite a problem because once you see that effect of things being sort of caught out of in and out of focus, it immediately forces a perception of scale onto the scene. We sort of mentally associate objects being called out of focus as being miniature object and photographs of miniature objects and our brain sort of immediately goes there. You may have seen circulating on the internet for the last 10 years, those photographs where they'll take a very large scene like a stadium or a cityscape and do the opposite. They'll actually force that sort of calling one thing out of focus technique onto it. And it gives it the effect of being a miniature, like a train set model or something like that, which is super cool. But in model photography, we pretty much always want to do the exact opposite of that sort of force a larger sense of scale. The last thing I would say about focal length aperture, if you have a camera, a DSLR, it's super worth spending a day and putting it in manual, full manual mode and going and trying to shoot photographs. Oh, way better than me explaining sort of mathematical relationships between all of those numbers. If you have access, I think you're, a lot of modern smartphones actually also have full manual mode in the camera tool that you can do this as well. So it actually forces you to make choices about aperture and focal length and you can see what the optical results are at the end. It's a really good way to learn. All right, so I'm gonna unshare for a second. All right, what do you need for a photo studio? Here I have multiple lights and objects and a really nice big backdrop with smooth background paper. These are all just fancy pants versions of the equipment that you could use at home. So if you, can I bring it in here? If you wanted to, you could use a desk lamp. You could use any kind of lamp. You could go on Amazon like I do and pick up these $8 LED lights that are battery powered that work really well. You could use flashlights, you could use your phone light. What you really need is two sources of light for any basic photo studio. One of those lights we'll see is sort of a more overall light and one of those lights is more pinpoint light. Just through those two, you can do a lot of things and depict a lot of different photographic scenes with them. The other thing you need is a background, a backdrop. I have a white one, but there's no reason it can't be gray, black, blue, orange, any color of material that you have. And the idea with the backdrop, I don't know if you can see it here, but it's to form a seamless transition between the wall and the surface. This is, if you walk into a professional photo studio, you'll see versions of these that are full room scale, so like 16 feet high or big enough that you can drive a car into it in some instances. The one I have here, I think is about 40 something inches wide, but we're only gonna be using a tiny slice of that today, maybe like 14 inches wide. So you can do this on a desk at home, you can do it on a nice chair, you can do it almost anywhere provided that you have two lights. So basic light terminology is that you wanna have one light, I'm gonna turn off my beauty light right here so we can see a little bit more of what's going on in the scene. You would have one light that acts as your sort of background light, sort of ambient light or what they might call your fill light. That light could in some cases be the lights of the room. These are LED lights in the room that are kind of nice, but they give a really flat quality of light to the entire scene, which is not always what you want in a model. A really good source of fill light is also natural light. So if you look, I don't know if you can see it, we do have natural light coming in a window that if I were to turn the lights off in the room would be a pretty good indirect source of fill light. Another thing I would point out is that you can actually get away with a photography studio setup, especially if you have a point and shoot or an SLR or an actual digital camera, you can get away with it in extremely low light settings. So I think this camera is automatically adjusting the light levels for the room, but I'm sitting in, I would say like less than 50% ambient light right now, which you'll still get very sharp bright photographs out of. The third thing that you can use for a fill light is actually to make a diffused light. So I have this super fancy LED light with a sort of diffuser box on it, but there's no reason that you couldn't use a desk light or a floor lamp with a t-shirt, a white t-shirt over it, or not if it's an incandescent light please, or a bed sheet strong in front of it, or you can go and pick up one of these $4 white diffusing umbrellas from anywhere that sells stuff. The idea is that you want to sort of scatter the light as much as possible so that it doesn't create hard shadows. So that's light number one. The other light that you're gonna need in your scene is called your key light or is your main light or your direct light. So this is the light that creates the sort of main shadows in the scene or lack of shadows, the main composition, sort of the main angle to which you're trying to light things. There's a bunch of different setups with your fill and key light and positions of them that have different names and different applications, but where I usually start is kind of what you can see in the scene of having a fill light on one side of the camera about 45 degrees away and a key light on the other side of the camera about 45 degrees away. This is a really good starting point and lets you tweak things. All right, before I get into showing the effects of these lights, I'm gonna turn the room light back on, super high-tech lights, super hard to turn on and off. I'm gonna show some software. So if you are going to be at GSAP or GSAP adjacent at some point, if you're going to be attending classes either in person or hybridly or remotely, if you're in the intro program right now, you will have access to the software that I showed today. The two software that we're gonna use are Lightroom and Photoshop. So if you haven't used Lightroom before is a super powerful, super clean, super quick tool to tweaking photographs and I'm only gonna show you something, a couple of things about it. The Lightroom has a lot of ways to alter your photographs sort of visually but what I think it's most sort of utility is in its administrative side to taking photographs. So almost any modern digital camera either an SLR or a mirrorless camera will have a USB out that allows you to sort of jack it directly into a computer which is what I'm doing right here. If you're taking photos on a smartphone, there are I believe apps that can sort of cast images directly into Lightroom on your computer or you can always have them just automatically uploading to a drive to access easily from Lightroom. I know this seems sort of like nitpicky on how on your workflow and how you handle and use files but the name of the game in digital photography is that you're gonna take a lot of photos and anyway that you can tweak your workflow to streamline photos coming from the camera into the software, it's going to be incredibly advantageous for you. So I'm gonna share again so that you can see. All right, this is Lightroom, it's also my dog. The way that Lightroom works is that it gives you kind of like a little developing studio and the thing that I'm doing here which you can see in this little window in the middle of the screen is tethering my camera. So quickly unshare again and you'll see that this camera that I have pointed at the scene is our camera that we're using for the photography setup today. It is wired directly into Lightroom so that if I take a photograph, get a little bit of focus on that. All right, there you go. If I take a photograph, it automatically pops into Lightroom. What could you do in Lightroom? I'm just reading the chat about my dog and the dog is just too easy, best dog in the world. In Lightroom has a lot of things that you can do but in this sort of panel on the side are sort of preset options that you can tweak. So I'm gonna get my zoom thing out of the way even though you can't see it you can see on the right here that you have all of your controls over exposure and contrast and color balance. One of the things that I typically like to do in these photographs is take them. I find that, I don't know if it's just my cameras or the scenes I set up, I find that the photographs are coming out of them a little warm and they don't have that sort of cool, crisp quality of model and product photography. So I take the color balance a little bit into the blue realm and then increase the contrast a little bit. And so you can see it's a pretty sharp looking photo. The shadows are minimized on the ground. There is no discernible background because it's the smooth transition from the flat.  Do you mind moving the camera connection to the top if it's not like physically but in this window so that we can see the shadow at the bottom of the model a little bit better? Oh yeah, yeah, yeah, yeah. Thank you. And then also do you create like a preset for each like shooting series or are you? That is exactly what I'm gonna talk about right now. I just want to address the question in the chat now. So I'll- Yeah, so what I do, okay, sorry, go ahead. I just, if I'm gonna bump in periodically, if more questions show up, I'll just mention them as we go so that they can get into the discussion. Yeah, absolutely. So I've taken this photograph in actually, let me take another photograph. I actually had a preset on there already. All right, so this is actually what it looks like straight out of the camera. It's a little yellowy orange. It's a little washed out. So maybe I wanna do a tone correction and I wanna take my color balance, you know, that far to the left and I want to increase the clarity which is kind of like a sharpness and contrast setting a little bit. All right, so I like that set of adjustments I did to it. In your little filter menu down here at the bottom right, you can go save current settings as new preset. So I'm gonna say Josh 05. Now the coolest thing about tethering your camera, which is what I'm doing right now with a cable, you can also do this on an import of any set of photographs is that you can tell them to import with a preset applied to them already. So you don't actually have to go through every photo and tweak. So in the case of tethering, what I do is change the develop settings here to my own user preset. Where's Josh 5? I might have to reset it for Josh 5 to set up but Josh's preset 01 is very similar. So I'm gonna use that one. So now when I take a photograph, comes in with the preset on it. Likewise, I have black and white presets that I've used and you can make any adjustment on top of the preset after you've already brought it in. All right, so right now I'm just working with the ambient, the single ambient light in the room. What happens when we start adding the lights that we were talking about are fill light and our key light. So you can see right now it's a sharp photo with a good lens. It's taken in about, I don't know, 25 millimeter focus length. So that's about what your iPhone would do. So I'm gonna turn the fill light up and turn the room lights off. Looks a little washed out in the background here.  So immediately you can see there's a sort of presence and a crispness to it that there was not when there was a sort of the wash of ambient LED light in the room. So next let's turn on the key light. So I just turned on a more sort of directly less diffuse light on the other side of the model about 45 degrees away. So you can see it's a very different photograph. The idea is that you play with these fill and key lights until you find a depiction of the subject that you like. The little bit of trial and error to it at first can switch the size of the shadow on an object and bring out its form a little bit more. So one of the things that you'll notice in here is that the shadows on the ground are a little bit more prominent now that I'm focusing on key light. I actually like in this case at this angle. Just a quick one minute warning, Josh. Okay, right. So I'd say this is a spot where I like the balance of light. I like how sharp the objects are and I like the preset on it. So what we're gonna do is take up break now a moment of silence. You're free to stick with us, but we'll be back in a little bit more than eight minutes and 46 seconds. Lila, is there anything you wanna add? Nope, you're muted. And I'm back. Thanks, everyone. So the last thing we looked at, if you can see in my background right here, is that we found a balance of fill and key light that we liked. And a share. Now, there's a couple of things that you could do to tweak this. I think that I might want my background to be a little brighter, which means I might increase the fill light or bring it closer. But as a base, the lesson is just to sort of find a sort of working look that you like. So I'm gonna do something a little bit crazier now. And oh, one thing I wanna talk about is, so these are two lights. I have very fancy LED photography lights that are very easy to use here, but your two lights by no means have to be fancy photography lights. So this is a probably $8 light from Amazon. And then this is my, if I can get my phone, this is my phone's light, drastic. So the light is cooler and it's harder and more targeted because I have it closer, but with a combination of something to diffuse this light, like if I used my white umbrella, I can also move my sort of key light in my phone around the scene as I want and get different shots. This is something where you might also wanna play with the ambient light a little bit in the room as well to bring it up. But there's no reason that you need fancy lights to do this. It's just easy for me in terms of consistency. Okay, I'm gonna do something a little bit more complicated. I'm gonna zoom out with this lens and construct a little bit more of a scene. All right, so I did this in practice. We'll see how bad I mess it up now. The beauty of these objects that are made in this course is that they're intended to tile and test light in different ways. So they're really good for staging, different combinations. It's like there's always the utility to having movable models. Models that are not sort of in their last stasis are not in their sort of final resting. Please don't touch me or I'm gonna fall apart state. Models that have a bit of a variability to them are capable of capturing many states simultaneously. Okay, I'm gonna reshare now. Camera one, camera two. All right, so a couple little adjustments to my scene. I also have a fancy tripod, which you do not need. I would, however, highly recommend investing in a small clamp for your phone if you're gonna be using your phone to take pictures. These are minimally expensive objects, just a couple bucks, something that holds it in place. They even make tripods, like little rinky dink, plastic tripods for iPhones and Android phones that do a great job holding them up in place. If you're gonna be making a small photography studio at home, excellent, excellent choice. All right, so let's say reframe this a little bit. There's always this sort of perilous, is the whole thing gonna fall down? Nature to these models, which I think is part of the joy. All right, so I have a pretty stable and smooth composition there with the lights I was using. Let's see what this looks like right now. So I've been talking about two light setups, which is kind of the bread and butter of photography lighting setups. There are also three light setups or four light setups, more light setups. You can have as many lights in your scene as you want. I find that it gets the returns that you get for multiple lights are often diminishing once you start adding them because they start canceling each other out, overlapping. When I use a third light, I like to use it for very specific purposes. For example, there's something that's known as a rim light or sometimes called a hair light. Let's see if this stays. Let's see if it's also not in frame. So a rim light, it's called a rim, it's called a hair light because in portraits, it highlights a sort of halo of fuzzy hair around the perimeter of somebody's head, sort of giving them almost an outline effectively. So you can use, it gets a little tricky in model photography and product photography setups because it's often difficult to get a light behind your subject without getting that light in the scene. But if you can play around with it, often your phone light, if you have a way to prop it up will work really well. You can create these sort of highlighted backgrounds with it as well. So when I use the third light, it's usually I'll flip it in the background as sort of a rim light. You can also physically light the background itself. So this is something usually with a little bit more drama that James Ewing does a lot in his photography is that he uses stage lights as sort of lighting effects in the background like spotlights or for example, you'll see him use lights as an effect that might create something like a false sun in the background. If I turn my show lights down, you can see this a little bit more drastically. So once you have your thing in place, your model in place and you have the sort of basic understanding of how moving the lights around works, you can do a lot with it. One more thing that I'll show is if you can't see what I'm doing, toggle my speaker view into the frame. What I'm trying to do now is I'm gonna turn my fill lights down, key light down and pop my crazy light in there. And then I'm going to sneak, this is the Bob Ross portion of the show. We're gonna have a happy little human. Thank you for your patience. This is a delicate process. Another thing to invest in, a cheap good set of model figurines of people, animals, anything. Buy them at different scales. I'd say you could get them down to probably about a 32nd inch scale which is about one to 400 which makes a person very small. That's like half a centimeter at that point. Up to these people which are, I don't know what scale they are, but they're about three centimeters in total height. Having interchangeable elements like that allows you to do a lot with a scene that has only a few parts. So in professional photography setups, the sort of control and direction of light is a lot more specific and artful and they'll spend hours sort of dialing in exactly how light is hitting something. The way they do that is by including some of the light with objects or what they call flags, holding things in front of the light or using the sort of barn door shutters on light to control that. I would say that in our model photography here, that's not something that we typically get into. We sort of paint with light from the broad scale but I encourage anybody to dive as far into that as you want to. One other thing that I would show though as a sort of peripheral is that you can also procure cheap acetate film or they call gels. See how close I can get this. I can sort of start to paint the scene with colored light as well. This is something that is, just about like every contemporary moody portrait of somebody I'm sure, very, very on trend right now. But I think what the cool part about it is, is this is something that is physically constructed in the scene. It's not an after effect in Photoshop or anything else. I don't know if you can see what I'm doing. We can. Okay, good. But all I've done, turn my lights down, well that's moody. So I've selected two very high contrast colors here and I'm obviously not adding enough fill light to make it work. But you get the idea and these are just really cheap colored translucent pieces of transparent pieces of plastic that can sort of further shape the light situation in your scene. All right, so last thing I'm gonna talk about in terms of, so all of these photos that I have now in this sort of film strip in Lightroom are things that I can all access at the same time. I can go back and apply tweaks and modifications universally to all of them. I can go into each one individually and sort of tune it how I want to see it. And then I can also export them either individually or on mass from Lightroom. So Lightroom is a really good tool to work as a sort of intermediary between your camera and wherever these photographs are going, whether it's Photoshop or elsewhere. The last thing I would talk about is, so some of the, I'm gonna switch back to our slideshow for a second. So this photograph, for example, is something that I took from the end of your show two springs ago, and that was on the 400 level of Avery Hall. So this model, if you'll forgive all the dust all over the camera because of the shop, I think the scale of this model or the size of that column that you see in the foreground is no more than two or two and a half inches. So this is an incredibly small model. You can even see the laser cutter burns on the chairs, which are very, very small objects. The way that this model, the way that this photograph forces an understanding of scale in the scene is by trying to catch everything in focus at the same time. Likewise, this is a bigger model, but it's still not very big. And you can see that everything from the very foreground to the very background, maybe not the very, very background is almost entirely in focus. Likewise, this photograph is from inside of a model that was constructed at, I guess the scales don't really make sense in these photographs, but size does. So I'd say like the roof of the volume that we're in right now is probably only three inches across. So it's a very small model. It's pretty big overall, but overall is a small model that sense of perspective and scale has been forced by capturing everything in focus. This is a model by Christian Keras that was, this was an exhibition probably almost 10 years ago at this point, more photographs of Christian Keras as models. And while these models are clearly absolutely incredible and their depiction of tectonics in space and material, one thing that is slightly lost for me on them is the sort of suspension of disbelief as you get into the foreground and start seeing the ground blur. So that sort of blur of the foreground material immediately takes you out of understanding it as being sort of flexible in scale. So how do we mitigate that? I'm gonna turn my room lights back on and I'm gonna show you a technique called focus stacking. So this is a specific thing in Photoshop that's a really easy tool to use, but it's a very powerful tool in letting you sort of fake, very powerful or very expensive lenses with very cheap equipment and get a depiction of an architectural model scene that sort of fools you into thinking the scale is not what it is. Let me just assemble. Thank you, Wendy Wong for your models. So I'm going to very hastily construct as cute as possible an architectural scene. What I'm taking is just small handcrafted models and objects that are kicking around the making studio, either left behind or used as demonstration pieces. I don't know if you can see these, but another cheap but valuable acquisition are sponges and miniature trees. I did a better job at this in my dryer on, but I'm working fast, bear with me. All right, so what I wanna show is that every an important thing to know about the camera you're using or the lens you're using or your phone that you're using as a camera is to test its minimum focus length. With phones, they're actually pretty good at having a very short focus length. So in other words, you could take a photo of something very close up, like a piece of paper with text on it and only be two or three inches away and get a focused picture. Camera lenses are a little bit different. Not every camera lens, especially ones that are zoom lenses are good at focusing very close to the subject. That's because they take special sort of optics and pieces of glass in the lens that not every lens has. Lenses, some lenses are made specifically for that type of photography. They might be called macro lenses. And some lenses just coincidentally have very short minimum focus lengths. But that minimum focus length is a really good tool, is a really good asset to have in a lens. And this isn't gonna take me long. I'm gonna wrap up shortly. But what I wanna show is basically this scene, it's adorable. So I have my little scene and I know that the, I'm gonna go back into Lightroom one more time and I'm gonna take a photo here. So even at a generous aperture for this photo, 6.3, I don't wanna go too much higher than that. At this sort of distance from the subject, it's really hard to catch everything in focus. It's a super sharp photo, it's super beautiful, but it's only in focus in the foreground. Likewise, if I go back and I try to make sure that something's in focus at the back end of the scene, only the back end of the scene is gonna be in focus. So the question is, well, how do you get everything in focus? The first thing I would tell you is try your phone camera. Even if you're using an SLR, since your phone has such a small lens, it's actually good at capturing a broad depth of field. One trick that you can do to fake it is to take a series of photographs, making sure that you are not changing the perspective of the camera at all or minimally, take a series of photographs ranging from in focus in the foreground to in focus in the background. If you're using a smartphone camera to do this, like I said, a lot of the modern camera softwares will actually have the ability to focus, to change the focal length on them. So now I have this big stack of photos that are all in focus in one spot. What I'm gonna do is export them from Lightroom. And I'm not gonna show you that stuff because it's pretty self-evident, it's just select the ones that you want, you select the range of photographs that you want at the bottom, and go file export, and it'll prompt you with a number of settings. What I'm trying to do is go into Photoshop and let's not save that. And in Photoshop, instead of opening a file, I'm going to go straight to scripts, load files into stack, browse for the files. And I have cheated and already exported. Josh, we still see Lightroom, just making sure you know. Oh, you can't see my, like, window that's in the front? No. Really? Okay, hang on. When you reshared. Okay, how about now? Here we go. All right, so sorry. Thank you, Lila. I went into Photoshop, and then instead of opening a new file or starting a new file, what I did is I went in file scripts, load files into stack. And then I browse for them, and I've cheated and exported them already. In this load into stack, is there's an option to attempt to automatically align source layers. Check that. All right, so now this does its magic in aligning the layers, which even though I had it on a tripod and nothing moved, it's important because when you change the focus of the camera, it actually changes the frame. Tiny bit, but it still changes. All right, so now you can see if I hide these layers one by one, that it pans focus through the whole scene, but it's never entirely in focus. So it has that illusion of being miniature. But what I can do is select all of the layers, and then in the edit menu, auto blend layers, there's this stack option. Now stacking is the word that they use for blending the in focus regions of photographs. It's used in all kinds of photography, miniature photography, but also night photography and astrophotography. Okay, and then what this does is it actually finds through some sort of sharpness and edge algorithm. It finds the in focus portion segments of every photograph that you've put into the stack, and it selectively masks out the out of focus portion of everyone. It sounds like a sort of a clunky choppy operation, but as you'll see, as long as it's been able to align the photographs well, it can make a really good seamless composition. So here you have, you can see down in the bottom right, this part of the sponge may have been sort of too close to the camera to be caught in focus, or it might be a problem with the mask. I could go in there and correct it a little bit. But now you have this photograph of the scene where everything is in focus from front to back. So it's completely sharp from the first object to the last object, and that you start to see it in this a little bit, but this is how you really start to free your models and photographs of models from the illusion of being forced into a particular scale. And if I were to take the time to drop people and other elements into them, it would all be caught in focus as well, and the scene really starts to come to life. Okay, so that's the sort of basics of two light photography and the sort of little accessories that you can put into it. Reiterate, you can do all of this at home with clothes pins and white pieces of paper. The last thing I would show is a couple of photographs of what that photo shoot at Never Built New York looked like. So here you see Lightroom operating in the foreground with this enormous 12-foot wide stage. See, James is assistant working at Lightroom. Oh, no, James is in the photograph as well. We actually liked this silhouette on the wall of all of the models so much that we took a photograph, we staged a photograph of it and that became one of the official photos at the end. This is that photo that you saw of just the three models. This is the smoke being blown on to the Frank Lloyd Wright model. But you can see these are enormous stagings. You can see he's using black acrylic plastic there that is a mirror for the base to simulate water, which is a pretty awesome effect. That black acrylic came back several times in the production. But this is what a photography shoot is. It's people laying on their bellies on a gallery floor for 12 hours at a time, meticulously crafting the perfect shot. So this is how you do stage craft. Hopefully today you saw that you can get pretty convincing results from much less time as long as you just follow the basic rules of the setup. Okay, that's all I have to talk about. I don't know if anybody has any questions about what they've seen today or the shop in general, but I know we've gone sort of an hour and 30 minutes already. I'm happy to wrap myself up or take questions. Sure, so everyone now has the ability to unmute themselves. If you'd like to ask questions, you're of course also welcome to write it into the chat if you'd prefer. I just wanted to reference one quick thing. I'm just gonna share my screen quickly because I wanted to let you guys all know that in addition to this video, which will be available on the events website, one of the things that I wanted to show you is that there is a page called Graphics Project. It's arch.columbia.edu forward slash graphics dash project. This is a series of sort of like informational events that we do every year. We try to record them. Some of the recordings are missing. The thing that I wanted to draw your specific attention to is this model photography guide. This was written by one of your colleagues and alumnus Ronald Young and it includes a downloadable PDF. It's 68 pages. It includes a lot of what Josh showed you today. Wait, my share is weird. Sorry about that. Yeah, Ronald is an amazing photographer and communicator. So definitely look at that. Right, so like for example, here is what I'm, the page that I chose to show you is like the sort of natural light options. So this is literally almost identical to what Josh's setup was today, but it is like a drawing example of it. So this is gonna be the perfect sort of addition to what you've seen. It also includes, for example, all of the equipment that is available from the GSAP-AB office and like how to reserve it. So this is gonna be a really valuable tool for you when you're on campus. It includes like, you know, a bunch of things but also all of the settings on the DSLRs that are available from the school and how to manage them. And then also all the way down to a tutorial of how it works in, to edit them in bridge and then also like different perspectives of your models, what an elevation is like the, you know, et cetera. So this is a really valuable tool that we put together for you to help you develop your portfolios. And so we just wanted to make sure, I just wanted to make sure that you were aware that this exists. So if you don't know how to use Adobe Bridge, there are instructions. So this file again, specifically is already on the website. If you go to the school website, arch.columbia.edu, forward slash graphics project. I'm gonna also just to show you like a little hack of getting, like using the website. If you search in the directory for any item. So like if you click on directory here and then you're looking for something specific, you can go to it in the alphabet. And so graphics project, this is how I navigate the website. Anything that I need to find, you can find in the thing. But if you click on model photography details right here, it's literally just the PDF that you can download. So super easy to access for all of you now and you can make proxies of Josh's setup at your home immediately. Yeah, I would add that this, so AV has equipment to rent at GSAP. Additionally, this sort of studio setup that you see behind me is a resource that is typically just rolling open to students who wanna come in and take photographs with models. It's sort of subject to the tragedy of the common sometimes. So it requires everybody to sort of take care of it. And we don't keep a camera out, but you'll be able to bring your own camera and just sort of slap it on the tripod, plug it in, use the light, start taking pictures, or in conjunction with using a camera from AV, you can bring it down here. But we try to keep this around sort of like after final reviews time, we pretty much keep this set up as much as possible and open a lot of the time. You'll see people are in here from, wee hours of the morning taking photographs.


With St. Patrick's Day right around the corner, the Bemidji Parks and Recreation Department has been busy preparing for their annual shamrock shuffle. For seven years, the five and ten-k shuffle put on by the Bemidji Parks and Recreation Department has been one of the department's most popular runs. Trophies for first through third place are available as well as other fun prizes. The shuffle begins at the Sanford Center and follows part of the city's trail system. With weather looking to be ideal for the run, organizers are expecting a fun and full turnout. Since I've started, this is the very first time it's landed on St. Patrick's Day. So we are expecting record numbers. We're anticipating possibly more than 200, but right now we're shooting for 200. So this is a record year for us. Everyone is encouraged to pre-register on the city of Bemidji's website, but if not registration for the shamrock shuffle, we'll begin at 8 a.m. with the race scheduled to begin at 9. If you enjoyed this segment of Lakeland News, please consider making a tax-deductible contribution to Lakeland PBS.


Hey guys, I came across this blog post on 41 machine learning interview questions by Roger Huang It has some pretty interesting questions that covers concepts applications and research in machine learning They have decent answers too, but I'll provide my own interpretation for 10 of these questions Depending on how you guys like this. I'll make answering interview questions a series on the channel No, these are interview questions. So some responses will be terse You don't have time for stories over the phone. That said, I'll highlight some questions that I found interesting so that you get a better understanding Note that at any point in the video if you think that I've answered something incorrectly or have a better explanation then feel free to call me out in the comments down below and Provide your own intuition. We can all learn from that and with that. Let's get started What is the difference between probability and likelihood? two entities involved here Data, which is a set of observations D Now D is a set of N samples with their corresponding labels For example in an email classifier to classify a given email as spam or not spam X is an email and Y can be a binary label spam or not spam The second entity is a model now this model performs some task like the email classifier just talked about It's parameterized by some theta Let's say these two entities are connected by some function F F is basically the model and this model has two phases a training phase and a testing phase During the training phase, you don't know theta, but you're given some training data D So this is like we have a bunch of emails and we also have their labels spam and not spam We use this training data to learn the parameters of our classifier. That is learn theta During this training phase given some D. We want to find theta that maximizes performance This is the essence of a method of optimization called maximum likelihood estimation After training we have the model so we have the email classifier as we now have the theta What we can do now is Testing the model on unseen data So we give the classifier some unseen emails and then it spits out whether the email is spam or not spam It's during this testing phase that given some theta We determine the chance of observing this outcome. That is probability so the difference Probability during the testing phase given a theta we determine the probability of observing the outcome and likelihood during the training phase given some outcome We determine the theta that maximizes the probability that such an outcome occurred Although they are similar in math notation. They have very different meanings Note that this is just my take on the difference. I had to reference certain sources to make sure I saw a great thread on stack exchange with different interpretations So check that out in the description Like I said in the beginning of the video if you have a better explanation to this answer or any of the answers that I provide Feel free to call me out in the comments down below What is base theorem and how is it useful in the machine learning context Base theorem allows us to determine posterior probabilities from our priors when presented with evidence or more simply a method of revising existing predictions given new evidence So how much more likely a is than b now is equal to how much more likely a was than b before we saw our new evidence Times how much more likely this evidence would be to occur if a were true than if b were true In machine learning base theorem forms the fundamental assumption of the naive base classifier a generative model for classification What is the difference between a generative and discriminative model? discriminative models learn decision boundaries between classes generative models learn the distribution of the classes themselves SVM is discriminative because we are creating a decision boundary. It is a maximum margin classifier after all Logistic regression is also discriminative as we learn a linear decision boundary Decision trees are also discriminative as each of the non-leaf nodes will partition space creating boundaries naive base classifiers are generative as they learn the distributions of the classes themselves Another difference is susceptibility to outliers Say we build a system where the distribution of the cross-validation or test data is different from the training data It is much easier to adjust the distribution then change the nature of a decision boundary So generative models work better with outliers here Again, if you are certain that the test data classes will have the same distribution as your trained data classes Then it might not be of concern. However, this can very well happen in the real world a mathematical take During the training phase many parametric models have the same start point maximum likelihood estimation This is what I talked about while discussing the first question distinguishing probability and likelihood During the training phase given some data. We determine the parameters of the model data such that the model performance is maximized In discriminative models, we maximize the conditional likelihood. That is we maximize conditional probability given the model parameters While in generative models like the naive base classifiers, we maximize the joint likelihood That is the joint probability given the model parameters What cross-validation technique would you use on a time series data set? In normal cross-validation say k-fold we split the data into k equal size chunks Use k-1 chunks as training and the remaining chunk for testing the model We can then average the performance of all the k-tests to give some performance measure A special case when k is equal to n is leave one out cross-validation However time series data isn't just a bag of points We cannot include samples in the train set that occur later in time than the test point So while performing leave one out cross-validation We select a point as a test set and only include the points that occur before it Temporally as the train set There are situations when we may want a multi-step forecast So we only include the points in the train set that are taken at least some time t before the test point How is a decision tree pruned pruning involves the removal of nodes and branches in a decision tree to make it simpler So as to mitigate overfitting and improve performance Say we constructed a decision tree and we have a validation set For each leaf node we can determine the node purity Ideally, we want the nodes to be as pure as possible for high accuracy But it's very easy to overfit so much so that the leaf nodes may only have a single data point We can mitigate this by pruning the decision tree Consider a method called cost effective pruning with the validation data determine the performance of the original tree t Now consider the subtree t1 and remove it from the original tree replace a subtree with a leaf if the validation set Doesn't have the significant difference in performance. We consider the simpler tree. Occam's razor comes to play here if pruned consider the prune tree as the original and Continue to the next subtree How would you handle an imbalanced data set if you have a lot of data to work with in the underrepresented class Then we can try random under sampling this involves getting rid of the overrepresented class samples from the training data You don't have to target a perfect one is to one ratio, but something close should work just fine If you don't have too much data to work with we can perform random oversampling Take the underrepresented class and sample with replacement until we get at the required ratio Synthetic monetary oversampling or smote is a technique where we can synthesize new data with minor distortions of existing samples Rather than just copies Ensemble learning algorithms tend to work well for data imbalances typically boosting bagging and random force techniques. Why? Aggregation tends to mitigate overfitting of a specific class What evaluation approaches would you work to gauge the effectiveness of a machine learning model? You can talk about cross-validation here. I'm not going to explain it too much because it's a subset of the other answers How do you handle missing or corrupt data in a data set to deal with missing values? We could perform data imputation The big idea is that if there is data that is missing you add a value But that data can be of different types for categorical values You can add a new category like no clue or other For numeric types you can impute with 0 and add an indicator variable showing that the value is missing the model will compute it for you How would you deal with outliers? Analyze the data with and without outliers We don't know if removing them is going to have some adverse effect after all That said there are two methods of dealing with outliers One is trimming where we delete the outlier all together and the other is winds arising Where we seal or floor the value to the closest that is either the maximum or minimum acceptable non outlier value This is usually the preferred technique Why us this question can be asked while applying to any role in any company Come up with an answer that's more than just a recruiter contacted me So I think I'm a good fit Ideally your response should tie your background with the current role proving that beyond any doubt You are a perfect fit as a grad student. I'm currently doing this on my job hunting escapade and That's it. That's 10 data science interview questions answered Hope this helps you crack those interviews or if you're not looking for a job You at least learn something out of this video If you like my teaching style show some love with like and comment down below your interview experiences I love to read them and that's bound to help someone out there just like you Now that the video is over a little about myself My name is Ajay Hawthor. I run a YouTube channel covering aspects on deep learning machine learning data sciences and other Frontiers of artificial intelligence If you want to get hooked on trending deep learning research or understand the mechanics behind some fundamental machine learning concepts Then subscribe to code Emporium links are in the description down below Thanks for sticking until the end if you still haven't had your daily dose of knowledge Click or tap one of the videos on screen for an awesome video, and I'll see you in the next one


You'll often hear our Australian championship drivers talk about being on the swept line or out in the loose and even row position being very important What does it actually mean? I've come down to the special stage here It'll be used in rally Victoria to give you a great example. We've got a left-hand corner here I've got my tires that I borrowed from Scott Peter for five minutes and you can see here inside of the corner swept line So much gravel's already gone We've got some of the rubber already being picked up and taken off the tires So this left front is going through the real rigors of trying to give the guys good grip Maintain its compound and give the car a good feel through the corners on the outside Loose stuff out in the looser guys will tell us out in the loose and couldn't get any traction So now our tires not dealing with that on this side It's trying to bite in through with the tread depth and give our guys a bite and maintain speed and not lose too much time So of course we've got to have adaptable tires to suit this Compounds that the drivers will choose from and of course if you throw the rain in it's got to cope with mud as well


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