@sandypac wrote:
I have been having a problem with using Auto ISO on my new Canon 7D Mark II. Even though the camera is set to Auto ISO lately in Aperture Priority mode the ISO is stuck on 100. If I switch to Shutter Priority or Manual modes Auto ISO works just fine, but in Aperture Priority and Program mode it stays stuck. But then when I take the camera back inside and reattach the lens, Auto ISO again works in Aperture Priority. Just seems to be out in the field I am having this problem.
You have to tell the camera the minimum shutter speed you want when using Auto ISO in AV mode, otherwise it will keep giving you a slower and slower shutter speed, rather than raising the ISO.
Canon DLC: Taking advantage of Auto ISO
Shutter Speed
Until now, one problem that kept many pros away from Auto ISO was that there was no meaningful control over how slow a shutter speed might be selected in low-light conditions. But with Canon’s recently introduced SLRs, the photographer can tailor Auto ISO to give exactly this type of control. A separate menu entry, Minimum shutter speed, provides the following settings:
Auto: Camera will continue to try to maintain a shutter speed of at least 1 over the lens focal length, changing ISO to maintain this as long as possible. The camera will tend to pick lower ISOs and slower speeds when using standard or wide-angle lenses.
User-defined shutter speed: Photographer can pick a speed from 1 second to 1/250 of a second and the camera will only go below this shutter speed after it has raised its ISO to the highest available setting, based on Maximum ISO set by the user under Auto ISO range.
