You can't have your low-light setting and clean image too - Gate House


August 08. 2012 2:00PM

You can't have your low-light setting and clean image too

What the heck is ISO and what does it do? That is one of the most common questions asked by neophyte photographers. In simple terms it's the sensitivity, or gain, of the digital light sensor.

Light is recorded by a camera's digital sensor and converted into an image. The ISO control allows the user to adjust the sensitivity of the sensor to best match conditions. A low ISO number is less sensitive to light and would be appropriate on a sunny day, while a high ISO setting is more sensitive and would be used in low light.

High ISO settings, like 800 or 1600, are fantastic for shooting in low light without a flash. Photos can be shot inconspicuously and often have a more natural look but there is a trade-off. As ISO settings increase so does digital noise. That noise looks something like speckles of sand on the image. High ISO settings impact sharpness, detail and the color of photos.

Increasing ISO is like increasing the volume of a stereo. The louder it gets the more it distorts.

So, if you want to fiddle with the ISO control, always use the lowest possible number for the highest quality reproduction. There may be times when high ISO settings are called for, such as indoor sports, but even then use the lowest number possible that will allow the appropriate shutter and aperture settings. As always, experiment and figure out what settings works best on your camera.