Tuesday, December 21, 2010

Give your camera a shake! Uh... and Flash!

In today´s example I will explain to you how to make fancy effects using the "2nd curtain" function of your camera´s flash control.

Thanks to Nele for letting me use this shot


Your camera is most probably equipped with a focal plane shutter, i.e. a shutter with two cloth, rubber or metal curtains. Winding your camera (something a digital or motorized analog camera does by itself after each exposure) pulls both curtains to one side of the film frame. When you press the shutter release, the first curtain makes its run to the other side, leaving the frame open for exposure. Then, the second curtain follows, closing the frame window and ending the exposure. Afterwards, upon winding, both curtains return to starting position.

Usually, your flash fires when the first curtain has opened completely and the second curtain has not moved yet. This is why there is a maximum shutter speed for flash synchronisation, because both curtains need to be open when the flash fires. Else, you´d get a shadow in your frame.
When you select that "2nd curtain" option, the flash fires just before the 2nd curtain starts to move into the frame. So all you do is choose whether the flash fires upon beginning of end of exposure time. That is all standard flash procedure, but what if you choose to expose longer than usual AND use the 2nd curtain?

You can now introduce some movement! Go ahead, zoom in, zoom out, pan the camera, tilt it, turn it! I turned it, obviously. This shot is exposed 1/8th of a second, enough time to give the camera a good spin and short enough to keep the background relatively dark (it was starting to get dark then). The light chains in the background help underline the movement and add a nice touch of color.

Flash light falls off pretty quick, so I can be sure that the light from my flash hits only my subject and nothing in the background, since we were three meters away from everything else in the frame. The flash was held on an extension cord in my extended left hand. Flash freezes everything, so no worries about shake or anything! The subject needs to be in relative dark, so it doesn´t register on the film during "shake phase". It should virtually be lit only by the flash. We stood in the shade of a big building, keeping the ambient light away from her. This way, each element in the frame gets its own exposure. Remember this one:


This is because the flash is so damn SHORT! If you want to register more or less background in a flash shot, "drag" the shutter some more or less. Easy. Give it some more or less time to register on the film/sensor. It doesn´t matter if you go 1st or 2nd curtain, but 2nd is more convenient for composition. Give it your own try.


I did some small tricks apart from shako-flasho. First, this shot is done in fading daylight on a late winter afternoon. Thus, I could easily mangle background light down to an evening look (like the so-called magic hour when everything turns blue). Plus, the shot is done in Tungsten white balance! I got the warm look on Nele´s face by slapping a full CTO gel on my flash ("Convert-To-Orange" turns daylight sources, such as flash light, into tungsten light by "warming" it up). The "wrong" white balance turns the existing light into deep blue, but the CTO gels give natural light back to the subject. I also added a half-CTO to get some extra warmth on her face - I mentioned before that flash light (in fact any light) falls off so quickly that nothing behind the intended subject gets lit, frozen or warmed up in any way.

The same day, some time earlier. Underexposure and wrong WB gives night character

You need to make the following setting on your equipment:

- set camera to tungsten (incandescent) WB
- gel flash to tungsten characteristic with CTO gels
- set flash firing to 2nd curtain
- set exposure time short enough to get subdued daylight and
- set exposure time long enough to register camera shake
- get whatever result you like by setting other WBs and using other gels

...and go shake away! 

No comments:

Post a Comment