I've been able to see that this model recognizes ISO from 10 to 51200, by looking in the detailed playback after making manual changes. This almost doubles the natural range on the camera.
In practice, the I-R value in miscellaneous follows the overide value that I had selected, but the I-M value appears 50-60% larger, and the detail in playback follows the latter number. If I set ISO to about 22,000 the I-M value is negative (and may be truncated because of the sign and space allowed).
I'd like to take advantage of this increased range as far as possible in the custom auto iso feature in CHDK.
I can't find instructions that cover the parameters in build 1825, firmware 100i, namely "second alternative minimum shutter" and "second alt max ISO." How should these be set in relationship to the first overrides chosen? The 2012 guide doesn't cover these parameters. What do they do?
The sx40 doesn't have a HI setting. Ignore choices for these, or set same as AUTO?
The camera seems to be picking slower shutter speeds than the constraints I've set. I'm not sure what I'm doing to cause this. Do the IS and User values affect this in some fashion?
For a scene with measured Ev of 8.5, and max ISO 3200, min shutter 1/500, IS=2, user =2, It holds at 800 ISO, f/2.7 and shutter goes to 1/50.
Also, why can't max ISO values override above 3200? This is the max value without CHDK.
There's something in the camera itself causing some of this, not CHDK. Without CHDK, Auto ISO goes to 3200 only in sports mode; all other modes seem to stop at 1600. I've read the Topic 7824 about ISO above 800, but I started a new one because it didn't address settings, etc. Hope this doesn't confuse things.
IN trying out various settings I occasionally get a lock-up and shut down.
Again, thanks for a wonderful product. Any help on any or all of this will be deeply appreciated.
