#44. "RE: How do I get sharper, in-focus pictures? Want to learn!" In response to In response to 43
It's a common technique when you have known aperture and shutter speeds - or when you don't want to go below a certain level. For example, you could use it if a subject is moving in and out of shadows. For example, you might set aperture wide open and shutter speed at whatever it takes to freeze motion.
Just select Manual Exposure mode and set your Aperture and Shutter as needed. Then use Auto ISO with the limits set as needed. I typically choose a high end of ISO 3200. In Auto ISO the ISO will adjust to the lowest level that can achieve your desired Aperture and shutter settings. If it reaches minimum ISO - ISO 50 - the next stop will overexpose the image since there is nothing left to adjust.
Metering works like normal - choose Matrix or Center weighted depending on the scene and subject. Exposure Comp can be dialed in as needed.