The closest I can get to that is using Tv that allows for higher shutter speeds for birds in flight or action if need be.Or, if you are up for it, write a Lua / uBASIC script to do exactly what you want.
I'm curious - what does "True Auto ISO" in manual mode mean to you? You set the shutter speed and aperature / ND filter values and the camera adjusts ISO to get the right exposure ?
lol - yeah - lets say "Auto ISO in Manual Mode" (reason I say "True", below)
I must confess - the directions for setting Custom Auto ISO befuddles me...
Can someone please help me set my G12's Auto ISO limit to 3200 please? I just don't get it...
I want my shutter to often remain at 1/1600th so I need that upper ISO limit for overcast days (reason below)
- I prefixed with a "True" because my Canon 50D said Auto ISO in Manual mode when if fact it remained ISO 400 - always. Then my 60D - comparatively - DID have "True" Auto ISO available as an option - meaning all settings manual - but you had an option for Auto ISO if you choose.
Then I got the G12 and when I saw that "Auto ISO in Manual mode" actually meant "ISO 80" (!!!) - it was a throw-back to my disappointment with the 50D. So... I love "True" Auto ISO in Manual Mode - but there does not seem to be the demand by the masses for it to be a feature in CHDK. And it beats the heck out of me how to write uBasic scripts ;-) ... who could I approach/sweet-talk?
I am a wildlife photographer primarily, and for birds in flight (BIF) I like to keep my shutter on my DSLR between 1250-2500, and my aperture between f/6.3 to f/9. Add to that the fact that when tracking a bird in flight the background is always changing - thus giving different exposures - thus my desire for Auto ISO to come to the rescue.
Of course - such action photos are demanding even for a DSLR - and all the more a challenge for the G12. I could not hope to get the same quality of focus or exposure using the G12 vs a DSLR - but I know the convenience of Auto ISO - and it ... ticke me off, shall we say, that Canon purposely crippled Auto ISO in M Mode on the G12, and so many other models - when its one of the most practical & convenient tools to have for action shooting.
In the mean time, I use Tv mode with Auto ISO set up to 1600 and my shutter typically at 1250-1600. I have to have faith/hope that the aperture 'wildcard' which the G12 chooses in Tv will have enough depth of field (DOF) for me to get enough of my subject in focus when I do not have my DSLR handy.