C.Fn I -8 Safety Shift
This works in the shutter-priority AE (Tv) and apterture-priority AE (Av) modes. When the subject’s brightness changes erratically and the correct autoexposure cannot be obtained, the camera will change the exposure setting automatically to obtain a correct exposure.
2: Enable (ISO speed)
This works in the Program AE, shutter-priority AE, and aperture-priority AE modes. When the subject’s brightness changes erratically and the correct autoexposure cannot be obtained, the camera will change the ISO speed within 100-3200 automatically to obtain a correct exposure.
---C.Fn I-12 Set shutter speed range
Disable:The settable shutter speed range will be 1/8000 sec. to 30 sec.
Enable : The settable shutter speed will range from the highest shutter speed to the lowest shutter speed set with [Register]
Register : The highest shutter speed can be registered within 1/8000 sec. to 1/250 sec., and the lowest shutter speed can be registered within 30sec. to 1/60sec. After entering the settings, select [Apply]
---C.Fn I-13 Set aperture speed range
Disable:The settable aperture will range from the camera-attached lens’ maximum aperture to minimum aperture.
Enable : The settable aperture will range from the smallest to largest aperture set with [Register]
Here I quote the author Pekka Saarinen from his review of the mkIII telling us how combining those Custom functions achieve auto ISO.(
"(...)When you combine this with custom settings for limiting shutter speeds and apertures you can set up a shooting environment with some insurance for success. For example I have set minimum shutter speed to 1/60, set ISO safety shift on, set ISO to 1600 and Tv mode to about 1/160. Now what happens when I shoot a live event is that when selected shutter speed is not possible with ISO 1600 Mark III raises ISO to 2000, then 2500 and 3200. When in Av mode and ISO 3200 is reached, it starts lowering shutter speed - but not below 1/60, this I have set to ensure reasonable stopping of movement without photographer having to change all settings during shoot. Now all we need is M mode ISO shift.(...)"
This is indeed a different than Nikon's but looks very flexible already. Or am I missing something?
Hey, but I recall seeing safety shift on the 40D ! Let's see...
C.Fn I-6 Saftey Shift
This works in the shutter-priority AE (Tv) and aperture-priority AE (Av) modes. If the subject’s brightness changes suddenly and the current shutter speed or aperture becomes unsuitable, the shutter speed or aperture is shifted automatically to obtain a suitable exposure.
No #2: Enable (ISO) here and no Min Shutter C.Fn or Min Aperture C.Fn...
And now we're reaching the end of the post : "why oh why did he bother us to dwelve into those manuals?"
Simple. I WANT these custom functions (or any real improvement of the autoISO) on my 40D and I want other people to start voicing their opinion on this as well.
It seems a lot of people haven't realized yet what flexibility this simple feature can bring to action photography with rapidly changing lighting conditions. Michael Reichmann from Luminous Landscapes went even further and proved how useful it was on a simple candid shot (
I'm no Canon firmware engineer but I somehow feel we could have it pretty easily (same generation cameras, digic III, etc...). Canon has to start improving its cameras through firmware someday.
What do YOU want?
Thanks for hanging on this far!
Just for the kicks : "Coming up next,
-Why does our 3" LCD only display tiny embedded low resolution jpegs?
-Why wouldn't Canon implement 450D liveview phase detection focus to the 40D firmware?"
The principle of Auto ISO would be, if I'm not mistaken :
-On aperture priority, when a lower limit shutter speed is reached and exposure cannot be insured ->
push ISO to reach or surpass that minimum shutter speed at the selected Av.
-On shutter priority, when a desired shutter speed cannot be reached with maximal aperture ->
push ISO so that desired shutter speed can be reached.
-On Manual, when both aperture and shutter speed don't allow for exposure ->
push ISO to allow for exp.