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12-06-2010, 01:53 PM   #1
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Problem with new K-5 with focus/noise

Hi all:

Just got the K-5. I am excited, but have an issue that I hope is nothing more than me making a silly mistake. I was hoping someone could point this out for me.

Attached are two images from a shoot I did this past weekend. These are just test/metering images and are cropped from the original. One is underexposed and perhaps the other slightly, too, but both were shot at ISO 80 at f 6.7 with the DA* 16-50. I mistakenly set AF to AF-C. They are JPEGs of the RAW.

I also attached one I worked on. I like it, but it is one of the few.

I know the two shots are somewhat underexposed, but all of the images from the shoot are very similar: not quite in focus. It can't be shooting in AF-C, could it? I am going to do some testing calibrating the AF, but was hoping I am missing something.

When I received my first K-7 none of my lenses came to focus under any micro adjustment to the AF.

So, is there anything I am missing?

I thought maybe my depth of field was too shallow, but nothing in the image of Catherine and her son on the floor (black background) are in sharp focus--I was about 6 feet away, which means my DOF was shallow, maybe too shallow, but I focused generally on Catherine's shirt/chest area.

Thanx all for your help!!!


Last edited by candgpics; 09-28-2012 at 07:11 PM.
12-06-2010, 02:16 PM   #2
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One question: did you check your lenses for focus misalignment with the K-5? Although the lenses may have aligned perfectly with your K-7, that doesn't automatically guarantee alignment with the K-5.

- Jason
12-06-2010, 03:02 PM   #3
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I'd say they were well underexposed, and that is a problem in itself, but probably easily corrected with the K5.
Focus can be off for so many reasons that it is hard to say with certainty, but you should do more testing and adjust if necessary. In no way do I see this as a camera problem, given the information here. About 99% of my problems are "User Error", and I find it the most common issue encountered.
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12-06-2010, 03:29 PM   #4
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Unfortunately your images don't have EXIF data, but from your description of ISO80 & f6.7, well that's going to be a challenge indoors to keep your shutter speed up fast enough to freeze movement without flash. The softness in the images could be subject movement or camera shake due to slow shutter speeds.

I agree though that just because your lenses needed no adjustment on your K7, doesn't mean they wont on your K5.


Last edited by twitch; 12-06-2010 at 03:53 PM.
12-06-2010, 03:38 PM   #5
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Doubt it was DOF. You didn't list a precise focal length, but assuming 35mm, your DOF at 6 ft distance and f/6.7 on an APS-C sensor should be about +/- 1 foot from the focal plane.
12-06-2010, 04:23 PM   #6
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QuoteOriginally posted by lawjbm Quote
and are cropped from the original
There's part of the problem too. If these are 50% crops they actually look OK.

In the absence of more information about your shooting situation, the usual solutions for sharper images apply - use a tripod, provide more light, expose correctly, use a higher shutter speed, use DOF to your advantage, don't put crappy filters on your lens, shoot at maximum resolution, shoot in RAW and use a good RAW convertor to extract maximum resolution out of your files etc etc.
12-06-2010, 06:31 PM   #7
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Calibrate your lens to the camera. Just because it was fine on the K7 doesn't mean it will be fine on the K5.
12-06-2010, 06:53 PM   #8
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Hi:

Thanx so much for the comments. All were done with off camera flash with Cybercyncs. The manner in which I shoot (distance, f stop, modeling light, etc.) were pretty typical, though I often shoot at f/8. Shutter was 180th/second.

I will play around with the AF micro calibration for a bit. Any other suggestions?

Thanx so much again.

12-06-2010, 07:04 PM   #9
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QuoteOriginally posted by lawjbm Quote
Hi:

Thanx so much for the comments. All were done with off camera flash with Cybercyncs. The manner in which I shoot (distance, f stop, modeling light, etc.) were pretty typical, though I often shoot at f/8. Shutter was 180th/second.

I will play around with the AF micro calibration for a bit. Any other suggestions?

Thanx so much again.
We really would need more info. Focus under modelling light? How bright? Any focus hunting? Did you focus a second time and checked it didn't change? Which focus point? Focus and recompose? 100% crop? Focal length? AF selection?

The most common problem is that the (rather large) area of the AF sensor picks up contrast from the neighborhood of the point of attraction.

It happens to me all the time and a firmware patch to read out 50% of the center spot would be highly appreciated by me.
12-06-2010, 07:43 PM   #10
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Hi:

I used center focus, got AF confirmation--again, nothing different than how I use my k7. Shot in manual. I will re-check how I did everything to make sure I am not missing anything embarrassing. My concern is that lll of the images were not in sharp focus. It is not like some were and some were not.

I say modeling light--I use daylight balanced flourescents as my ambient fcousing light. A while back I used to use tungsten with CTO gels. Again, nothing different from how I have used my k7 for the past year.

Thanx so much for your comments and assistance.
12-06-2010, 08:35 PM   #11
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Update:

My DA*55 needs about +6 to be in focus. I will try the DA* 16-50 now.
12-06-2010, 09:09 PM   #12
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Update:

The DA* 16-50 seems better at +6, as well, but I will test more, and test some of the other lenses I have.
12-07-2010, 03:09 PM   #13
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Hi all:

Back to Amazon it goes. I played with other lenses and perhaps I am being too critical, but I had a similar problem with my first k7, except that no AF micro adjustment worked. I went through two DA* 16-50s before I got a good one and then my DA* 16-50 required 2 repairs due to SDM failure.

Anyway, frustrated, but Amazon's replacement policy is very generous (I will get a new one tomorrow and I can return the one I have after). We order quite a bit from Amazon and their service is great.

Thanx all for your help.
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