 Ken Pang |
Anyone Have Any Test Patterns for Lenses? Hey everyone. I just got a repaired lens back from Canon, which I sent in because the images weren't sharp. They said they've realigned everything and that it should be okay now. But I still want to test them. Does anyone have a image they could email me of fine lines crossing and bright colours etc? The standard stuff they use to test the quality of lenses? Thanks...
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John A. Lind |
Ken, This must be the "new" used lens? I know you're "Down Under" and this source is in the U.S. . . . Edmund Optics: They sell the "1951 USAF Resolution Targets" which are among *the* standards for evaluating lens MTF's. They're found in the "Testing" category, under the "Test Targets" sub-category of their on-line catalog. To try to print one yourself would be difficult, if not impossible. They also have other targets for measuring everything from color accuracy to DoF. The cheap method for making a "ballpark" assessment is to photograph a newspaper page with fine print or a very large topographic map with many contour lines, very closely spaced, such as one of the Grand Canyon. These do not yield any photometric values though. Use the absolute finest grain film possible for this. In color: probably Fuji Provia 100F (RDP III). In B/W: Kodak Technical Pan developed for continuous tone (not for copy work). Typically the slides/negatives are then examined under a high power microscope. -- John
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