PASM Quandary

Posted: July 12, 2015 in Cameras, Photo equipment, Photography


Riding the subway, I was asked by a newbie Nikon user how to adjust the aperture of his lens. I was very impressed that the photographer knew that he had an aperture and I showed him the “A” setting and had to jump off at my subway destination leaving the fledgling with an abbreviated lesson.  I feel compelled to continue the discussion (and needed an excuse to post this cute “chimping pic”). ASPM, MSAP, MASP, PMSA, PSMA (just don’t call it SPAM) is simply a designation for setting your camera to the following:

  • A  Aperture  — you designate the lens opening and the camera will set the shutter
  • S Shutter — you designate the shutter speed and the camera will set the aperture
  • P Program — the camera makes an “educated” guess on the proper setting
  • M Manual — you make all the decisions

So which to use?  I have my cameras set to A 95% of the time. Most often I am concerned with either isolating the subject (lens wide open –  f1.4, f2.0, f2.8) or garnering complete focus from up-close to infinity (lens “stopped” down to f11, f16, f22). Naturally there are a great many other reasons and variables to consider, such as camera movement, optimum f-stop for image quality, etc.  Can’t wait for the next subway question!


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