Once considered strictly a tool for the casual snap-shooter, Auto ISO has recently grown in stature to the point that some pros and advanced DSLR enthusiasts expect to use it in certain fast-paced situations, or where lighting may make radical changes from shot-to-shot.
Auto ISO has evolved in EOS cameras, adding features and functionality as new models have been introduced in recent years. The EOS 7D Mark II has — without question — Canon’s most advanced Auto ISO operation ever. With this camera, critical users who want Auto ISO will feel very much at home. Here are some of the EOS 7D Mark II’s Auto ISO capabilities:
The Auto ISO range can be different than the available (user-defined) range for a manually-selected ISO, and are entered separately in the “ISO speed settings” menu, in the 2nd Shooting Menu screen. Users can set whatever lowest and highest ISOs they feel comfortable using for Auto ISO, factoring in both image quality concerns and the lighting they expect to be working in.
One aspect of Auto ISO is pre-setting the system so that when light drops and shutter speed (in P or Av mode) is forced below a pre-defined level, the camera will automatically raise ISO and preserve at least that minimum shutter speed. EOS 7D Mark II now allows the user to pre-set anywhere from 1/8000th of a second to 1 full second as that minimum shutter speed.
Previous EOS cameras limited the fastest “minimum” speed to 1/250th of a second, which often wasn’t sufficient to avoid blurs when shooting moving subjects, and/or working with telephoto lenses. What happens if you set 1/8000th of a second? The EOS 7D Mark II will simply do its best to always shoot at 1/8000 in P or Av modes, varying ISO (and aperture, in P-mode) to do so, and only allowing slower speeds when you’ve reached your pre-set maximum available ISO, and declining light levels mean slower shutter speeds are the only answer to continue to get proper exposure.
Another option for pre-setting the minimum shutter speed before Auto ISO goes to a higher ISO setting is “Auto.” In the past, this was simply 1/ lens focal length, and with standard or wide-angle lenses, the resulting slow shutter speeds sometimes meant speeds that were dangerously close to risking blurs from subject or camera movement. Think about it — in a fast-paced situation, such as (for instance) indoor wedding candids with a 16-35mm lens, do you really want speeds dropping as low as 1/15th of a second?
EOS 7D Mark II now offers a 7-step scale, to further fine-tune what the camera will do when you’ve set Auto for minimum shutter speed. It still uses 1/ lens focal length as the base, but with considerable adjustability. Three settings on the “+” side allow you to dial-in 1, 2 or 3 stops faster shutter speeds than whatever your current 1/ lens focal length setting is. And the “–” settings allow up to 3 stops slower speeds, for instances where you’re using Image Stabilization, or are otherwise confident that slower shutter speeds will be the right answer for you.
Particularly when working with zoom lenses having an extensive zoom range, the Auto setting gives flexibility to work with Auto ISO, and have appropriate shutter speeds for your longer focal lengths, and still allow for reduced — but safe — speeds at wide zoom settings.