[QUOTE]\nYou have to remember that unless you are using manual exposure mode\nthe mode you are using will limit things. Meaning using as described\nthe aperture priority exposure program raises the iso up to the limit\nspecified. Given the fixed aperture the only thing further which can\nbe done if this does not allow enough light to satisfy the exposure\nprogram is reduce the shutter speed. On the fly you can modify this by\ndialing in _EV exposure compensation which is then an input to the\nexposure program. specified.\n\nOne alternative is to use shutter priority and set shutter speed., but\nyou then lose control of the aperture. If you use full manual exposure\nyou will keep aperture and shutter settings and float iso. However,\nthis only provides a higher light level floor from your prescribed\nshutter and aperture settings. If you still need more light there is\nnothing the camera can adjust.\n[/QUOTE]\n\nI have ny recently started using auto ISO. While I think I understand\nthe basic theory, I still have to understand how it works in the real world.