K5 Back Focus issue solved

Started Jun 10, 2012 | Discussions thread
il_alexk Senior Member • Posts: 2,326
Re: K5 Back Focus issue solved

muratscott wrote:

... I still am afraid to mess up with the precise AF values of all of my about 10 lenses including two FA primes .I've spent so much time for AF adjustment on each of them and I don't want to ruin it all...I'll do some more web search and then make an attempt to correct my Tamron...
Any tips and help are welcome...

10 um in the debug mode is equal to 1 step in AF micro-adjustments; it should be easy to readjust your lenses without re-calibration.

You simply need to deduct the Debug AF correction value from all AF corrections of your lenses (divided by 10). For example, Debug AF correction of +40 is easily compensated with AF adjustment of -4.

This however implies some limits for the range of the AF corrections in the Debug menu. If you use too much of the correction in the Debug mode, you won't be able to compensate it for all your glass.

Say, all corrections for your lenses are within -2 to +4 range. This would limit the Debug mode corrections to be within the range from (-10+4)*10=-60um to (10-2)*10=+80um.

Enjoy and good luck.

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 il_alexk's gear list:il_alexk's gear list
Ricoh GR Pentax K-5 IIs Pentax smc FA 50mm F1.4 Tamron SP AF 70-200mm F/2.8 Di LD (IF) MACRO +3 more
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