But I would rather have 1/2000 or even 1/4000 when I can get it because horses move fast. I don't want to hard set the shutter at 1/1000.
What you speak of goes entirely against the principle of 'adjust everything else within limits, then select the minimum ISO that gives you an acceptable exposure (±EC, or exposure compensation, for the bloke above).
What you're asking for is to give high shutter speed a priority, allowing ISO to go higher than the camera could get by just setting a longer shutter speed (and therefore lower ISO).
That just goes against the entire philosophy of Auto ISO. What you're asking for is essentially 'use highest ISO possible within my limits, float everything else'.
Seems like a pretty limited case scenario to me. Seems to me you could just do one of the following:
- Shoot in Tv mode, where the camera will prefer wider apertures, then increasing ISO. You even have EC available.
- Shoot in M mode, select the aperture/shutter speed you prefer, camera will select lowest ISO necessary.
What's wrong with either of those two options?
Also, I ask again, what would you guys propose be the method of changing EC in M mode using Auto ISO? I would, for example, say: hold M.fn function down & use wheel to adjust EC.
Also, this whole 'defaults to ISO 400' thing... think that's because that's about unity gain for the 5DIII (and 5DII)? So they decided if you're using flash, you're probably deprived of light, so going below 400 would be undesirable, & going above 400 doesn't help much anyway since some people hold that there's not much advantage to shooting above unity gain ISO anyway & you have a flash to help anyhow...
Is that sound reasoning? I myself am unsure...