By now it’s common knowledge that when shooting film, it’s important to not underexpose to hold on to shadows, and for digital it’s key to save the highlights. I’m going to advocate, however, that with modern digital sensors, it’s prudent to shoot underexposed all the time.
You’ll hear many people argue that there are certain situations where underexposing has its benefits, but not all the time. While it may sound counter-intuitive to the folks arguing to “get it right in the camera” all the time, there’s a method to my madness.
The first major reason to underexpose is to get a faster shutter speed. Sports photographers know that if they’re in a tough environment (for instance, a night college soccer game) then underexposing will give them the precious extra stop or two of shutter speed. The difference between 1/250 and 1/500 could mean the difference between getting a blurry mess or a sharp shot. The penalty comes on the back end, where you have to process that photo out so that it’s properly exposed, but with modern software, batch processing a large amount of files to the same exposure isn’t challenging.
But beyond the faster shutter speeds that are possible, there’s the practical benefit of protecting the highlights. Even dialing in a third of a stop or two thirds can give you the leeway to prevent a sky from blowing out, or a white shirt from blending into a white background.
I first started doing this mostly by accident more than a decade ago, when screens on digital cameras were so poor that I thought I was overexposing all of the time when I set the meter to 0. Instead, I found that things looked just fine on the computer, and I was just being fooled by chimping on the camera. But I still gained that exposure latitude, and the practice just stuck.
Of course this only applies for raw files. If you’re shooting JPG, you don’t have the editing headroom. Don’t do it!
What do you think? Is underexposing all of the time crazy? Do you do it too? Leave your thoughts in the comments below.