I'd agree that the error is no big deal, if tolerance really meant "plus or minus." It doesn't. When was the last time you read a test report that found that a lens gave you more of what you thought you paid for? A 20 mm that measured at 19.4 mm? A 200 mm that gave you 205 mm? An f/2 that was f/1.9? When all the error falls on the "cheaper to make" side, that's called cheating.
When Amateur Photographer reviewed a 300mm lens several years ago, it found the focal length to be 280mm. But the editors added that just about all "300"s were really 280s, and that Leitz was the only maker to label theirs honestly (Leica 280 mm). Bob Harris wrote: I believe I read in one of the reviews that the "industry standard" was to be within 5% of the rated focal length. So a claimed 20mm lens could be anywhere between 19 and 21. No big deal. Paul Franklin Stregevsky - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
