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11-09-2007, 09:16 AM   #1
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FA 50mm F1.4 AutoFocus problem

Hello, I just got my copy of FA 40mm F1.4, quite happy with it. But sometime I found the Auto Focus is abit off even K10D confirm it is in focus, at wide open to F2, is it normal?

but beyond F2, man I love this lens :P

11-09-2007, 09:24 AM   #2
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Yes this is normal.
The AF uses light from a light path that equals roughly the light from f5.6.
Since one has a larger DOF at f5.6, the AF confirms focus when anything within this DOF range, roughly, is in focus.
f1.4 has a much thinner DOF.

Also note that the AF sensor is much larger than the little red square in the viewfinder.
11-09-2007, 09:29 AM   #3
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oh.. i see, thanks blende8. learn something new today, now I wish that FA50 has quickShift focus like those other lens I have

Last edited by vizjerei; 11-09-2007 at 10:21 AM.
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