Is my lens sharp as it should be?

• Unal

  Member

  August 13, 2007 at 1:11 pm

  This is the question that I’d love to answer myself without taking it into professionals. How do you guys determine either your lenses are sharp copy or not? I only have 2 lenses at the moment (17-55 IS & 100mm macro) and I’d love to find out that either they are a good copy or not.

  PS: this is cross-posted in some other forum with the hope of as much response as I can to find out how to test a lens

  Thanks,
  Unal
  Thorsten

  Member

  August 13, 2007 at 2:18 pm

  http://photo.net/learn/focustest/

  Bear in mind this is not a “real world” test. The only way you’re going to know if your lens is sharp or not is by using it in day to day scenarios. Shooting brick walls or pieces of paper with scales on them doesn’t represent the type of images or the conditions you’re going to encounter in everyday use, so is of limited value IMHO.
  jb7

  Participant

  August 13, 2007 at 5:11 pm

  Thats a good link-
  I was photographing a ruler myself the other night,
  but only to find out the closest focus on the 10-20 stopped down-

  I’m not sure that it properly addresses the question though,
  it seems more like a focus test than a sharpness test-
  although the two can be related-

  I had a Nikon F3 that wouldn’t focus with wide-angles once-
  I had to have the camera lens mount replaced, because it had warped-

  Similarly, there is sample variation between lenses-
  some lenses will be sharper than others,
  even from the same batch-

  Other things influencing sharpness will be camera shake-
  shutter vibration, contrast reduction due to flare, diffraction-
  lots of things can conspire to degrade the image-

  If you are testing,
  a tripod can be a necessity,
  and the mirror should be locked up to eliminate that variable too-

  j
  SteveFE

  Member

  August 13, 2007 at 8:41 pm

  I only ever judge by the actual results I get. Cat’s whiskers are a good real world focus test, as are eyelashes and skin detail on portrait subjects, and distant skyline detail like transmitter masts on the horizon for landscapes and infinity focus.

  I would say, test sharpness by comparing with a Micro-Nikkor 105/2.8 on the same camera (yes, it can be used on Canons too), but that really would be unfair on just about every other lens ever made ;) It’s the most brutally efficient, clinically sharp lens I’ve ever used. Your 100mm macro should be almost as good though.