Many current cameras allow for Auto ISO to be used in all shooting modes, including Manual mode. Most pros would immediately think “Why would I EVER use Auto ISO? I always want full control!”
And yes, I confess I used to think the same way, but I have found more than a few situations where this setting can make a big difference. Good examples are pretty much any stage performance where the lighting changes rapidly, sometimes almost instantly, like theater plays, and concerts.
Another classic situation is the wedding photographer’s nightmare: you are shooting the ceremony inside a church with window light, the doors open, the couple quickly exits the church and within seconds you have to adjust all of the settings. Been there, done that. Auto ISO would let you work at higher ISOs while the couple is in the church, and seamlessly switch to lower ISOs as they step outside without missing those priceless moments.
Not convinced? What about a car or bike race, or any football game that takes place in the early morning or late afternoon, where half of the field is in direct sunlight and the other half is in deep shade? Many moons ago, in the “film era” I was covering sport events for a local newspaper I had to carry two cameras, each pre-set to different settings and even different film speeds. The exposure settings on Camera A would be pre-set for the “sunny field” and Camera B for the “deep shade field, and as soon as the play moved into the other, I had to quickly and constantly swap them. I can honestly say I do not miss those moments one bit.
More examples? A wildlife photographer following an animal, that might be hiding under a tree and suddenly move into bright sunlight, and here’s the situation that got me into this topic; adventure photography and more specifically rock climbing, with very uncomfortable positions and angles where the shutter and aperture can’t be easily changed and the subject keeps constantly moving in within dramatically different lighting situations.
When facing up to the sky and then down to a very dark canyon Auto ISO is a godsend.
Some cameras like Canon’s 5D Mark III allows the user to pre-set a minimum and maximum ISO range, as well as a minimum shutter speed used with Auto ISO — if the shutter speed drops below the user-set value, the Auto ISO will automatically be raised.
When shooting video in Manual Mode, one can set a specific ISO (for example, from 100 to 6,400) or let the camera automatically adjust the ISO on the fly. So we can manually pre-set and lock our shutter speed and aperture, but when the light changes the camera adjusts the exposure by only varying ISO. This is especially handy when shooting from a moving vehicle when we typically go through widly different scenes from super bright to extremely dark.
Another situation where we have used Auto ISO with great success is doing one continuous shot with a Steadicam inside a subway station and following the actor walking outside. Not only the light changes drastically but we don’t not have easy access to the camera settings while recording.
Keep in mind that when shooting video in Auto Mode (P, Tv, or Av), most cameras will automatically set Auto ISO by default.
As you can see, Auto ISO is a very useful setting when the light is changing rapidly (performances), the shutter speed and/or aperture need to be set to match a specific effect (sports), or when changing settings is not easy (Steadycam). And this is why Auto ISO is not (always) a bad word.
Eduardo Angel is an independent Technology Consultant, Educator, and Visual Storyteller based in Brooklyn, NY. He currently teaches at The School of Visual Arts and the International Center of Photography, and mentors the photography program at the Savannah College of Art and Design.
He is a co-founder of the idea production company The Digital Distillery, author of popular filmmaking courses on Lynda.com, and regularly shares his thoughts on technology, photography, and cinema on his website eduardoangel.com.