Checking calibration is a simple, quick procedure that they usually (maybe often) don\'t charge for.
If something needs to be done internally (I\'m talking about a lens that\'s decentered, has a tilted element, etc., not just a focus adjustment) it can be a fairly simple, straightforward thing requiring just a minor disassembly. Or it can be a several hours job.
Centering a 100-400, for example, requires removing all of the barrels, reassembling the elements onto a special jig base, centering the elements, then reassembling the lens. A 70-200 f/2.8 IS may require removing all the rear barrels, reassembling everything but keeping the third barrel piece off to allow acces to centering collars, centering the lens, then taking it back apart and reassembling with the barrel back on.
I\'m sure Canon factory service is much faster than I am, but the time it takes to optically adjust a lens runs 30 minutes for something really simple, up to 4 hours for more complex stuff. And remember the charge includes not just the tech\'s time, but access to a few hundred thousand dollars worth of equipment, software and space. (My very limited repair facilities include 2,500 SF of space stuffed to the brim with over 6 figures worth of equipment.)
I know I sound like an apologist, but \"just an adjustment\" makes it seem much simpler than it is. Also, people seem to confuse focus adjustment with optical adjustment. If a lens has an optical problem, all the focus adjustment in the world just makes a well focused soft image.
May 22, 2013 at 12:05 PM
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