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04-19-2010, 06:55 AM   #1
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Manual focus issue with K10D

I have used my Super Tak 50 1.4mm with my K10 many times in the past, but I recently had to do a firmware BF adjustment (V 1.30). The BF issue was solved using my F and DA series lenses. But I finally had the chance to get out with my Taks to do some "manual" shooting. ( I use the PENTAX adapter).
The results were far from acceptable with many shots out of focus on the focal points (Looks like BF in manual focus mode??).
If any one can weigh in on this problem, I would really appreciate it. I am a little baffled as to why a focusing issue would arise when focusing manually, and in manual program mode.
If this post should be in another forum, please advise.

Thanks


04-19-2010, 08:22 AM   #2
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Due to the design of modern DSLR focus screens, the viewfinder shows you too deep a DOF at f/1.4 - that is, there are things that are in focus in the viewfinder that won't be in the picture. So until you learn to recognize which part of the apparently-in-focus zone in the viewfinder will actually be in focus in the shot, focusing large apertures with the stock focus screen can be very tricky. I recommend practice using text on an angle, paying attention to which lines appear in focus in the viewfinder versus which turn out to actually be in focus. With practic, you can learn to anticipate the shift.

Many, however, simply replace the stock screen with a third party split prism screen.
04-19-2010, 09:29 AM   #3
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Yea, as Mark said I would look into investing some money into a split prism screen for your camera. One that is mentioned here alot is the Katseye focusing screen. It is set up just like the focusing screen in an older SLR so that your manual focus shots are in good focus.
04-19-2010, 09:31 AM   #4
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I have no issue at all with focus of my fast lenses on the K10D. I use regularly 50mm F1.4 and 85mm F1.4 lenses as well as a 135 F2.5. BUT I have installed a jinfinance diagonal split image vocusing screen. As marc says the DOF of fast lenses is so shallow, and the apparent DOF of the optical viewscreen so misleading, it is tough without the split image to get accurate focus.

I also find this to be true with fast Wide angle lenses because the DOF of the lens is so high, accurate focus is tough. Again the split image is a big help.

04-19-2010, 07:18 PM   #5
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Thanks

Thank you for all 3 replys, the information is appreciated and I will definately look intio the focusing screen issue.
I am still cannot figure why I was not having these focusing issues before using the same equipment.
I did some shooting today using some of my DA lens, in full manual mode, and everything was fine. So ??

Thanks
04-20-2010, 12:52 PM   #6
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As I said, since the viewfinder shows more in focus than actully is, it's kind of luck of the draw whether the thing you care about will happen to be in the part that is in focus for real or the part that isn't. That is, sometimes you'll happen to get your subject in focus for real, sometimes you won't. That's normal until you learn to recognize and anticipate which parts of the apparently-in-focus zone are *really* in focus (for me on my camera, it's the frontmost portion of that zone).
04-21-2010, 03:26 AM   #7
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QuoteOriginally posted by Marc Sabatella Quote
As I said, since the viewfinder shows more in focus than actully is, it's kind of luck of the draw whether the thing you care about will happen to be in the part that is in focus for real or the part that isn't. That is, sometimes you'll happen to get your subject in focus for real, sometimes you won't. That's normal until you learn to recognize and anticipate which parts of the apparently-in-focus zone are *really* in focus (for me on my camera, it's the frontmost portion of that zone).
Marc

I will definately "focus" in on your recommendations. So I can assume that you figure that this is everything to do with the screen, and not anything to do with adjusting the auto focus in the fimware (V 1.30)?

Thanks again.
04-21-2010, 04:16 AM   #8
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Adjusting the AF has no effect on manual focus. Manual is totally dependent on your eye, nothing else. A good split screen would make it easier.

04-21-2010, 09:28 AM   #9
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Correct. The only thing that *could* be off in the camera is the focus screen might be improperly positioned. To see if this is true, you'd have to do the sort of tests I described. It's *normal* that the viewfinder would show more in focus thn the picture - but everything in focus in the picture should be in focus in the viewfinder. If you find things are in focus in the picture that were *not* in focus in the viewfinder, that would mean the focus screen is not positioned properly. You could try removing it and reseating it, maybe adding shims if necessary. But there' very very very little chance this is the case, so don't even think about messing with until you've actually performed the test.
04-21-2010, 03:37 PM   #10
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You might want to try Katzeye focusing screen. Very good focusing screen using manual lenses.
04-21-2010, 03:51 PM   #11
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QuoteOriginally posted by Tall Guy Quote
I have used my Super Tak 50 1.4mm with my K10 many times in the past, but I recently had to do a firmware BF adjustment (V 1.30). The BF issue was solved using my F and DA series lenses. But I finally had the chance to get out with my Taks to do some "manual" shooting. ( I use the PENTAX adapter).
The results were far from acceptable with many shots out of focus on the focal points (Looks like BF in manual focus mode??).
If any one can weigh in on this problem, I would really appreciate it. I am a little baffled as to why a focusing issue would arise when focusing manually, and in manual program mode.
If this post should be in another forum, please advise.

Thanks
QuoteOriginally posted by wildlifephotog Quote
Adjusting the AF has no effect on manual focus. Manual is totally dependent on your eye, nothing else. A good split screen would make it easier.
Tall guy: I may have misunderstood your post. If you adjusted your K10D for the benefit of the AF lenses you listed then you very well affected the focus of the Tak as well.

Although wildlifephotographer is right that AF doesn't come into play and that you have to use your eyes, it does make a difference with when you see the green hexagon and even when the red center indicator lights up. If you rely on those or the focus trap method, you will get blurred shots.

I have a k10d with a katz eye prism and the lenses listed below. I went thru each and made an adjustment so that the focus indicator lights when the prism is perfectly aligned. I then made a list on paper and placed in in the side hatch where you connect the computer cable, etc. I keep my camera in the debug mode to quickly adjust the focus for each lens, including the manual focus lenses. Trust me it does make a difference. When you use a split prism, it is easy to see when the focus indicator is off. Ignoring the prism, the image looks fairly sharp due to the DOF issues Marc outlined.

Hope this helps,

Mark
04-21-2010, 07:22 PM   #12
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QuoteOriginally posted by Marc Sabatella Quote
Correct. The only thing that *could* be off in the camera is the focus screen might be improperly positioned. To see if this is true, you'd have to do the sort of tests I described. It's *normal* that the viewfinder would show more in focus thn the picture - but everything in focus in the picture should be in focus in the viewfinder. If you find things are in focus in the picture that were *not* in focus in the viewfinder, that would mean the focus screen is not positioned properly. You could try removing it and reseating it, maybe adding shims if necessary. But there' very very very little chance this is the case, so don't even think about messing with until you've actually performed the test.
Marc
Sorry for not reponding sooner, and thanks for your valued input. I will perform the tests you recommended and I will be definately be looking into purcahsing a split screen. I did check the focus screen that is currently "on board" and it seems to be seated fine.
There have been a couple of responses since, one with a different view, but first things first.

Thanks again.
04-21-2010, 09:36 PM   #13
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QuoteOriginally posted by Marc Sabatella Quote
The only thing that *could* be off in the camera is the focus screen might be improperly positioned.
Or the mirror.

QuoteOriginally posted by Tall Guy Quote
If any one can weigh in on this problem, I would really appreciate it. I am a little baffled as to why a focusing issue would arise when focusing manually, and in manual program mode.
It's strange that you could focus before, but not now. Other than a focusing screen, you might also want to try the Pentax O-ME53 magnifier loupe. It's what I use for manual focusing and I find it very helpful.
04-22-2010, 03:43 AM   #14
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QuoteOriginally posted by Laurentiu Cristofor Quote
Or the mirror.



It's strange that you could focus before, but not now. Other than a focusing screen, you might also want to try the Pentax O-ME53 magnifier loupe. It's what I use for manual focusing and I find it very helpful.
Laurentiu

I have tested both manual and auoto focus with my DA lens and there is no "visual" difference through the viewfinder, and I have always used theO-ME53 magnifier.

Thanks for your input.
04-22-2010, 01:34 PM   #15
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QuoteOriginally posted by Laurentiu Cristofor Quote
It's strange that you could focus before, but not now.
Such is the nature of random chance. It's like tossing coin and hoping for heads. Some people might get lucky and see it come up heads the first few times they toss the coin, but inevitably, they'll start seeing tails too. Same here. It's *always* - repeat *always* - a crap shoot due to the design of the focus screen as I explained. But sometimes you do get lucky enough for a while that you don't notice there is an issue. Took me a couple of years myself. Not that I had perfect success those first two years, but I blamed myself for any failures, and didn't start becoming aware that the camera was actually fighting me until much later.
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