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04-11-2012, 09:01 PM   #1
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Problem with K10D or DA16-45 lens

Recently noticed a lot of soft photos coming from my K10D and favorite DA 16-45 lens so I did a little test today using my wifes new Olympus e-pm1 to compare. All shots from tripod at f5.6 with 2 second timer.

#1 K10D at 45mm

#2 e-pm1 at 42mm

#3 K10d at 16mm 100% crop

#4 e-pm1 14mm 100% crop


Last edited by robert; 11-10-2012 at 09:45 AM.
04-11-2012, 11:01 PM   #2
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Check to see what's going on with focus:
#1 appears focus is about in line with the chairs, not the subjects on the table.
#3 is focused on building behind.
04-12-2012, 03:40 AM   #3
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I have a K10D and 16-45 also. My copy of the lens back focuses, which as calsan points out appears to be what's happening here. Unfortunately the K10D does not allow for per-lens AF adjustment.
04-12-2012, 06:27 AM   #4
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I read in the manual, and in an older thread that a soild light background will impact focus. If you shoot with a "busy' background, are you still having focus issues?

04-12-2012, 07:20 AM   #5
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The DA 16-45mm lens is not very robustly made, over time the zoom and focus rings become very loose so check if it needs to be serviced. The other probable reason is that you got a mirror box alignment issue. K10Ds and K20Ds have the reflex mirror resting on a single prong. With long and repeated use, the mirror is misaligned ever so slightly which in turn affects the AF accuracy. The only permanent fix is a replacement mirror box assembly. This issue cropped up among heavy usage shooters a few years ago. That's why the K-7 and current K5 have the mirror resting on two prongs.
04-12-2012, 11:35 AM   #6
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There is absolutely no possible way this is an example of backfoucs, at least, not in the usual sense of the camera trying to focus somewhere but instead focusing slightly behnd. The errors that result from that are measured in millimeters and fractions thereof, not in feet as appears to be the case here. DOF at f/5.6 would have completely masked any backfocus issues anyhow. No, what we have here is either the focus not engaging at all - are you sure you were on AF mode? - or else the camera simply having chosen to focus somewhere other than where you thought it was - perhaps beause you had a focus point selected that was over the background.
04-12-2012, 05:33 PM   #7
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QuoteOriginally posted by Marc Sabatella Quote
There is absolutely no possible way this is an example of backfoucs, at least, not in the usual sense of the camera trying to focus somewhere but instead focusing slightly behnd. The errors that result from that are measured in millimeters and fractions thereof, not in feet as appears to be the case here. DOF at f/5.6 would have completely masked any backfocus issues anyhow. No, what we have here is either the focus not engaging at all - are you sure you were on AF mode? - or else the camera simply having chosen to focus somewhere other than where you thought it was - perhaps beause you had a focus point selected that was over the background.
Nope I had autofocus engaged using center focus point and got the focus conformation light right where the heart is on the quaker oats box
04-13-2012, 08:43 AM   #8
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The focus "point" may have been centered on the the Quaker box, but it is plainly obvious that is not where the camera focused. As you may or may not realize, the focus sensors are actually much larger than the little red squares that appear in the viewfinder, and the background may well have been in range. It can and does happen that the camera will elect to focus on a more distant object within range of the sensor rather than the closest, if the more distance one happens to make a more attractive focus target. It appears that may be what happened here. Hard to say from just a single test picture, though.

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