Originally Posted by mdwh
The ISO setting just offers the modes returned by the camera driver - http://www.dpreview.com/forums/post/50107202 has some info, and it seems that other camera apps don't manage to support this option well either. I suspect the problem is that ISO isn't something officially supported by the Android camera API (at least pre-5.0), so 3rd party camera apps can only set ISO by going through some unofficial parameters.
After test driving this app on my Galaxy Nexus (toro running 4.4.4 OmniRom), it seems that manual ISO controls are being completely ignored. The modes I can set are Auto, 100, 200, 400, and 800. After snapping a bunch of pictures with ISO set manually to 100 and 800 (I was hoping to compare as historically photos with this phone usually have a lot of noise), and looking at the exif data, I'm seeing values of 320, 400, 428, 500, 640.
Perhaps my phone simply doesn't allow manual ISO controls so the app is falling back on a default set? Would be nice to not have the options display if they aren't functional. I can provide more information if it would be of any help. Most of these shots were taken with focus set to macro and white balance set to flourescent, although some were otherwise on full auto, not sure if any of that would be relevant.