Re: Eclair Cameras: Lens testing procedures

[Wade Ramsey <wramsey@bju.edu>]

Ian Marks wrote:

> I'm going to be shooting some lens tests soon and was wondering if 
anyone could suggest some procedures. Is there a standardized resolution 
chart I can use to evaluate sharpness and contrast? ....<

I use a set of USAF 1951 lens resolution chips I made into a chart.  This will allow you to read off the actual resolution in line pairs per mm. up to 80 lp/mm, although I have tested lenses that exceed that.  I don't know if anyone has updated this for higher resolution lenses, surely someone has.  

This will test the lenses, film gate, and film you shoot it on, so it isn't completely objective.  But if you test all your lenses at the same time on the same film and camera you'll have a good relative comparison between lenses.  After processing (I shoot on PX-Reversal and just dip process for 4 minutes or so in a tank of T-Max, D-76 or whatever film developer) you read the results off the film using a 20x magnifier.

Century Precision Optics might have a test chart for sale.

Wade K. Ramsey, DP
Dept. of Cinema & Video Production
Bob Jones University
Greenville, SC 29614

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