For camera bodies without autofocus microadjustment capability, how do repair shops calibrate a specific body and a lens combination suffering from the focus shifts (back and/or front focusing)?
These cameras have microadjustment capability, just not in a user-accessible way.
The exact method varies by model. Some have a software feature in an advanced (and secret) "debug" menu — the Pentax K10D, for example, had this. Others have physical adjustment screws or similar (like earlier Canon Rebel models). Or, repair centers may simply use shims.
To find the exact answer for a given model, you could either dissect the camera and look, or find the repair manual.
thanks for your answer. I was suspecting that those bodies do have it, albeit without exposing it to the end user. I own a Canon 60D and I keep wondering if there is a way to enable the microadjustment via software... Magic Lantern, perhaps?– insignumDec 20, 2012 at 20:52
@insignum For that specific model, check out Can I fine tune the autofocus on my Canon 60D to be more accurate? — although so far the best answer is "send it in".– mattdmDec 20, 2012 at 21:21
mattdm: Could you please elaborate about dissecting the camera. What exactly am I looking for inside? Also, are there freely available repair manuals for Canon models?– insignumDec 21, 2012 at 22:50