A Guest post by SusanG from Camelot Photography Forum.
I often am asked “what is the best shutter speed/aperture for such and such”. I’ve even asked the question myself. But in a way, we’re jumping ahead of the gun when we ask that. Instead, if we ask ourselves “Do I need more light or less light” for this image to work, we will have found the answer ourselves based on the exact circumstance that requires the answer. Because once we’ve determined that answer, we know that by narrowing the aperture and/or increasing the shutter speed we can reduce the light entering the camera. And by opening the aperture or slowing the shutter speed, we can increase it. Understanding Exposure and Stops is a keystone concept that will only help your photography. Whether you shoot in Auto or Manual. The principle does not change!
So, what does all that have to do with capturing contrast in our photography? A lot! Because contrast is affected by how much light we allow in when exposing!
Contrast in photography is the difference between dark and light. But it doesn’t end there It also refers to contrasts created with colour, tones and texture. We “see” these only because of light.
If light is what makes colours visible: What makes colours saturate in-camera (increase in strength)? That would be the amount of light. Remember paint boxes in kindergarten? How did we get stronger, deeper tones? We added Black!
And that is exactly how we get contrast and rich colour in our photography. We add “dark”. But how do we do that?
OK. Enough with the Theory! On to the Practical.
Contrast: The difference between dark and light
High Contrast: An extreme difference between dark and light
Low Contrast: A gradual or lesser difference between dark and light
Colour Contrast: Tonal differences, as well as Saturation levels, of colours
High Key: Mostly light including whites
Low Key: Mostly darks including blacks
No Contrast: Is a Whiteout in the Antarctic and very dangerous. Best advice is return to Base Station.
First, determine the “correct” exposure. All cameras have a light meter built in. It’s that little bar graph on your screen that has -2 on the left side 0 in the middle and 2 on the right. The minus side represents under exposure, the plus represents over, and zero represents what your camera thinks is the correct exposure. Learn how to use it!
Once you’ve achieved the correct exposure, compensate your settings by 1/3 to one Full Stop under. Now you’re adding “dark”: The black in the paint box. If you’re shooting in auto or semi auto (shutter or aperture priority) you can set the compensation in the EV (Exposure Value) Compensation menu and the camera will automatically underexpose by the margin you set. If you’re shooting in Manual, use your aperture setting to make smaller adjustments (aperture settings in most cameras are in increments of 1/3 of a Full Stop) and shutter speeds to make dramatic adjustments (as shutter speed in most cameras are one full stop up or down). Keep an eye on that light meter reading when stopping down manually. You want the needle to nudge over to the left (the minus side) of Zero. Each hash mark being a 1/3 increment of a Full Stop.
The basic guideline for getting the most contrast in a scene is:
Shoot with the narrowest aperture possible for light conditions
Shoot with the fastest shutter speed possible for light conditions
And if you’re already thinking of when the above does NOT apply, you’re further ahead on controlling and creating contrast then you thought 😉
SusanG is the Creator of Camelot Photography Forum, a MySpace™ Photography Site where anyone can find their new level.