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08-02-2015, 11:20 PM   #1
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Subjects turn out soft in 4/5 shots with various lens at large aperture. How to fix?

I've noticed that I need to take multiple pics of the same subject at F2.8 or less to get it in sharp focus. Even then it I'm not sure if I've gotten the subject sharp. I've tried micro adjustments without luck. Is there any service shop in the Seattle area where I can get this fixed?

08-03-2015, 06:30 AM   #2
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Is this handheld or on a tripod?
08-03-2015, 08:40 AM   #3
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Try it with live view on a tripod and good lighting. Live view should always focus correctly without micro adjustments. If that's good, try it handheld with live view and good lighting. Proceed from there to find the actual problem. Autofocus isn't terribly accurate wide open on fast lenses and the viewfinder is useless for it unless you switch out the stock one for something intended for fast lenses.
08-03-2015, 09:13 AM   #4
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Most lenses will seem softer than optimum wide-open. Also, Auto-Focus is not in its peak-performance zone at widest apertures. Stop down the aperture, manual focus, use a tripod, try Live-View with Focus Peaking, and possibly raise the ISO to get a faster shutter speed if motion blur is part of the issue. Most of all, don't pixel-peep at magnifications larger than you want to display or print.

08-03-2015, 12:45 PM   #5
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The focusing system has a range of what it considers "in focus". You'd be surprised if you try focusing onto a subject from infinity and from minimum focus distance! If you are using a long length telephoto-ish lens then your depth of field is very thin. What ends up being in focus can change easily. Consider if you wobble a little due to being unsteady or try to stay still in the wind then your pictures may be soft too. You may now find yourself needing to refocus. A tripod, like @Bagga_Txips mentioned above, could help. Same goes for the subject matter. With digital it can't hurt to retrigger the focusing and catch multiple shots.
08-03-2015, 12:59 PM   #6
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No focus peaking on a K5. He can zoom in in live view though.
08-03-2015, 03:15 PM   #7
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if the in camera micro-adjustments don't work for you, you could always try shimming your focusing screen. i remember having to do this with an old K10.
08-03-2015, 03:43 PM   #8
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QuoteOriginally posted by AquaDome Quote
Most lenses will seem softer than optimum wide-open. Also, Auto-Focus is not in its peak-performance zone at widest apertures. Stop down the aperture, manual focus, use a tripod, try Live-View with Focus Peaking, and possibly raise the ISO to get a faster shutter speed if motion blur is part of the issue. Most of all, don't pixel-peep at magnifications larger than you want to display or print.
Stopping down to F9-10, the sharpness is acceptable but the shots that I really miss are of a person and trying to get a bit of blur for the background. The subject ends up turning out soft

QuoteOriginally posted by jkomp316 Quote
if the in camera micro-adjustments don't work for you, you could always try shimming your focusing screen. i remember having to do this with an old K10.
What's shimming?

QuoteOriginally posted by narual Quote
Try it with live view on a tripod and good lighting. Live view should always focus correctly without micro adjustments. If that's good, try it handheld with live view and good lighting. Proceed from there to find the actual problem. Autofocus isn't terribly accurate wide open on fast lenses and the viewfinder is useless for it unless you switch out the stock one for something intended for fast lenses.
If I find out that live view gives me sharp focus while the viewfinder does not, where does the problem lie? Camera or the lens?

08-03-2015, 04:04 PM   #9
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live view is focusing directly off the sensor output. with the viewfinder you are focusing off the mirror and focusing screen.
08-03-2015, 04:27 PM   #10
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You shouldn't need to go to f/11 to get sharp focus on a face. I rarely stop down beyond f/8 for anything unless I'm shooting film.

Are you using the center-point for auto-focus? Is this a particularly low-light or low-contrast scene? Is it only with one particular lens? What lens? How soft is the focus?
08-04-2015, 07:01 AM   #11
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QuoteOriginally posted by photoleet Quote
If I find out that live view gives me sharp focus while the viewfinder does not, where does the problem lie? Camera or the lens?
If live view gives you sharp focus with both tripod and handheld, the problem is the AF fine tuning.

If it only gives you sharp focus on the tripod, the problem is more organic in nature -- i.e., you're not steady enough and should probably move to a faster shutter speed to compensate for that (which means a higher ISO since you might not want to go too open on the aperture if you're unsteady, since the depth of field narrows)
08-04-2015, 11:52 AM   #12
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QuoteOriginally posted by narual Quote
If live view gives you sharp focus with both tripod and handheld, the problem is the AF fine tuning.

If it only gives you sharp focus on the tripod, the problem is more organic in nature -- i.e., you're not steady enough and should probably move to a faster shutter speed to compensate for that (which means a higher ISO since you might not want to go too open on the aperture if you're unsteady, since the depth of field narrows)
I've noticed this even when I've been in the mountains on a sunny day so the shutter speed is quite fast and hand-held shouldn't be a problem. I'l check the Live View method. If it is AF fine tuning, where can I get that fixed?

QuoteOriginally posted by AquaDome Quote
You shouldn't need to go to f/11 to get sharp focus on a face. I rarely stop down beyond f/8 for anything unless I'm shooting film.

Are you using the center-point for auto-focus? Is this a particularly low-light or low-contrast scene? Is it only with one particular lens? What lens? How soft is the focus?
Yes center point. On a sunny day in mountains, various colors of clothes. I'd say I've noticed this in high contrast situations as well. Lens was Tamron 18-50 F2.8 and DA50 1.8.
08-05-2015, 08:09 AM   #13
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QuoteOriginally posted by photoleet Quote
I've noticed this even when I've been in the mountains on a sunny day so the shutter speed is quite fast and hand-held shouldn't be a problem. I'l check the Live View method. If it is AF fine tuning, where can I get that fixed?
Don't make assumptions. Test it like I suggested, be methodical, and narrow down the problem.

The best way to fine tune a lens IMO is LensAlign, using the FocusTune software, and following all the directions on their support forum carefully -- stuff like the specific distance for a given focal length, consistent good lighting on the target without glare on the lens, indoors where there's no breeze, with both camera and LensAlign very stable, only slightly defocusing about the same amount in the same direction each time with 5+ shots each at -10/-5/0/5/10, then run FocusTune, check where your best numbers are, and then do 5-10 shots at each point within +/-5 of that point, all without moving your camera even a tiny bit.

Once you get as close to perfect as possible in that controlled environment, you know the AF is working the best that it can, then if you're still running into focusing problems, it may be that you're not focusing where you think you are -- Pentax's focus points are larger than the dots on the screen indicate, and considerably so prior to the K3.
08-09-2015, 11:25 PM   #14
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Post a picture straight from the camera that shows the problem. Maybe you've overlooked an issue that someone else here can identify.
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