these articles might help the OP ( and others ):
Many enthusiasts spend a lot of money on camera gear and then want to know how good it is. While every experienced photographer can tell the optical qualities of a lens from fitting sample images there are ways beyond subjective quality evaluations. These are about testing lens sharpness and resolution using either an optical bench (which costs more than the average new car, so not really a good fit for "homegrown" testing), or shooting test charts and analyzing the results mathematically.
The article is about the latter: resolution testing at home using freely available test charts and software to analyze it.
Read more at:
Guide: DSLR Lens Resolution Testing at Home - Articles and Tips | PentaxForums.com
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How Sharp are my Camera and Lens?
October 1, 2014 Leave a comment
You want to measure how sharp your camera/lens combination is to make sure it lives up to its specs. Or perhaps you’d like to compare how well one lens captures spatial resolution compared to another you own. Or perhaps again you are in the market for new equipment and would like to know what could be expected from the shortlist. Or an old faithful is not looking right and you’d like to check it out. So you decide to do some testing. Where to start?
http://www.strollswithmydog.com/how-sharp-camera-lens/
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Have you ever run in to autofocus alignment issues with one of your lenses? Did you know that even if you experience front- or back-focus with a lens, it's not necessarily defective?
In fact, more than 70% of the time, you can fix the problem at home without having to send anything in for repairs, or echancing any of your equipment!
Read more at:
https://www.pentaxforums.com/articles/photo-articles/front-and-back-focus.html#ixzz5VcaOxF2g
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Fixing Front and Back Focus
Introduction
With the advent of digital photography we have become much more critical about focus accuracy. We're now able to enlarge our photos to 100% size on our monitors and look at them pixel by pixel. Inaccuracies in focus and other flaws which no one noticed or cared about in the film era are now blatantly visible.
Read more at:
https://www.pentaxforums.com/reviews/lens-align-front-back-focus/introductio...#ixzz5VcadJ2Hy