If an incident reading at the subject is f/5.6, is it necessary to set the lens aperture to f/5.6?

• A. No
• B. Yes
• C. Only for auto exposure
• D. Only for manual exposure

Answer: (A)

An incident reading tells you the light level on the subject and the exposure needed for a correct image at the chosen ISO and shutter speed. It does not force the lens to be set to that same aperture. You’re free to use a different aperture and compensate with the other exposure controls to keep the image properly exposed.

If you want more depth of field, you can stop down to a smaller aperture and equally you would need to lengthen the shutter or raise ISO to maintain the same overall brightness. If you want less depth of field, open up the aperture and you’d typically shorten the shutter or lower ISO to keep the exposure from getting too bright. In auto exposure modes, the camera will adjust shutter speed or aperture to reach the target exposure, so you’re not locked into the meter’s aperture either.