Monday, July 1, 2013
How To Use Auto ISO
When light is changing, consider employing your camera’s auto ISO adjustment
|This Article Features Photo Zoom|
For the longest time I considered my camera's auto ISO feature something only amateur photographers used. It was for people who didn't fully understand the intricacies of light sensitivity and exposure adjustments, I told myself. True, I'd long used aperture priority and shutter priority automatic exposure modes when a situation called for it, but still I had a bias against auto ISO. It's just that I'd never taken the time to figure out exactly when and why I might want my ISO to change automatically. Then one day a wildlife photographer explained to me just how valuable this tool is in his workflow, and I saw how it could work for me, too. Here's what he taught me.
In practice this means you can set your aperture to wide open (f/2.8, for instance) and your minimum aperture to 1/125th. The camera will automatically boost the ISO as needed to create a perfect exposure with a shutter speed no slower than 1/125th. And, if the available light allows for it, the camera will drop the ISO as low as possible and increase the shutter speed above 1/125th in order to minimize the noise that comes from higher ISOs.
Since high ISO noise has improved so dramatically in recent years, auto ISO has become a much more valuable a tool. The naked eye may not see a difference between ISO 400 and ISO 800, but it's sure going to see the motion blur created at 1/30th of a second instead of 1/60th. Both of those represent a one-stop difference, but it's the shutter speed that can mean the difference between a blurry photo and a sharp one.
However you choose to utilize it, one thing about auto ISO is very clear: it is not just a crutch for newbies or those who don't understand ISOs. In fact, it's a valuable tool for skilled photographers who want to be very deliberate with their exposures. It is yet another reason why it's so great to be a photographer with access to all of the technology of today: the possibilities are endless.