Photographer Jack Reznicki wrote an article on Canon's Digital Learning Center, explaining how Auto ISO enabled him to greatly improve his "keeper" rate when shooting street photography. He elaborated on the usefulness of Auto ISO and how it provided him " with maximum control over his camera in situations where the light changes dramatically and extremely quickly."
I am a wildlife photographer and do very little street photography. Auto ISO is not something I use often because the shutter speed assigned by the camera is generally not fast enough for me to get a sharp image of moving wildlife. I use the Aperture Control shooting mode and adjust my ISO before shutter release if conditions call for a change. You can see my work on MichaelDanielHo.com
Below is the article on CDLC on Auto ISO :
"One of the things I love to do when traveling is to do street shots when riding in a car. As a long time commercial photographer, I am usually working in a studio with an art director, crew, models, and tight layouts and parameters. So shooting out of a vehicle window while speeding down the road is very liberating and exciting. It’s the complete opposite of shooting in a studio. What I really love is that it helps your “visual muscles” and your shutter finger reflexes. When the car is moving 40 to 60 miles per hour, you either get the shot or miss the shot. And when you get it, you get great drive-by, slice of life shots. Like this shot below, which I took from a fast moving SUV in the Philippines.
After leading a workshop in Panama, my class thought I was crazy when they heard the click, click, click of my camera as our bus sped along the road. They all started doing the same after they saw the images at the evening review. In the old film days, and still in the digital age, I always knew that along with this type of shooting, I would have to accept great misses. I’d capture a great shot.... except for the fact that it was out of focus because of a slow shutter, too shallow of a depth of field, or the wrong exposure because we jumped from sunlight to shade too fast. Some of those missed shots just burn into your mind. When photographers get together to trade stories, one of the things they can all talk about is a great shot that they missed. Usually with film, if I “got” the shot then 30% to 50% of the time I’d be relatively happy. On a recent trip to Africa, I used my new favorite feature on both my EOS 5D Mark II and my EOS-1D X to get a greater percentage of hero shots with very few misses. I was not just relatively happy, I was deliriously happy as I got 90% or more “keeper” street shots on that trip.
The feature that changed it? Glad you asked. Auto ISO. In this day and age when the cameras are built like fine computers, we can have a lot more control over our cameras and how they work. Auto ISO gives me maximum control over my camera in situations where the light changes dramatically and extremely quickly. With Auto ISO, I have several options. And I used them all to get these photos you see here. The fact is that I don’t worry about shooting at a high ISO if I need to get the shot. In the film days, ISO 800 (or “ASA” 800 for real old timers) was about as great as we could get. Oh, we could also shoot at ISO 1000 if we wanted the “fine art” affect of golf ball sized grain in our shots.
With digital, I have shots that were done at ISO 1600 with “noise” that looks like a low ISO captured image. And that was the earlier digital days. Today, the technology allows us to photograph at ISOs that were simply unimaginable in the film days. Yes, I sometimes have to use noise reduction software in Canon’s DPP (Digital Photo Professional), Adobe Lightroom, Photoshop, or some other 3rd party software, but the results blow my mind. Canon’s capture technology, with their modern sensors and processing software, takes our shooting abilities to a higher level than ever before.
The photo below was shot not from a speeding car, but rather in a very dark classroom with a Maasai schoolgirl in Tanzania. I shot it at ISO 25,600. That’s ISO 25,600, not ISO 256! If you look close, you can see the fly on her face above her left eye. Remarkable. Did I know I was shooting at ISO 25,600? Nope. I was shooting outside in bright sun and I quickly ducked into this schoolhouse. I shot first, looked at my settings second. But I got the shot with the background kids in a great position because the Auto ISO saved me. It’s there, the great elements in a photo altogether for one moment, and then it’s gone forever. If I stopped to readjust my settings, I would have missed the shot. Either you get it or you don’t. Luckily, my camera was set to Auto ISO.
Outside, I had set my camera to manual with the shutter speed and aperture at set values and my ISO to Auto before I walked into the classroom. That’s just one of three modes I can shoot in with Auto ISO. On Manual, I set the shutter speed and aperture to the values I want and I let the ISO “float.” With AV or aperture control, I can set the aperture at the value I want and tell the camera the minimum shutter speed, up to 1/250th of a second. With the TV setting or shutter priority, I can set the shutter where I want it and the camera will set the aperture, usually the widest value in dim light. But in drive-by car shots, I want a very fast shutter speed like 1/1500th or faster and a decent aperture like f/8 or more. With the varying light that I get while traveling in a car, I get ISO speeds of 200 to 6400. But usually it falls in the ISO 800 to 1250 range, as are the images shown here. Love it, love it, love it.
If you want to read in more detail about this feature, Eduardo Angel wrote a great article, “Taking advantage of Auto ISO.” For me, Auto ISO is a hidden gem in my camera’s features and the most impactful, lately, along with the incredibly better noise at higher ISOs. As we say and demonstrate on the Canon In Action Tour, the technology today is expanding our abilities as photographers, enabling images that weren’t possible before. Better photos through better technology."