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08-22-2010, 10:51 PM   #1
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K-x - Random unfocused shots...

About 2-4% of my photos taken with my K-x have nothing in focus. The camera didn't front or back-focus; One simply cannot find anything in the frame which is halfway sharp. There's no sign of mirror slap in these photos (though I did get my first slap shot at 1/90th last night - crap!). There's no motion blur. It happens at different shutter speeds, including at very high speeds. It happens at different focal lengths and with both kit lenses. Different lighting conditions, always with plenty of light.

Am I the only one? I love this camera when it does what it's supposed to do!

08-22-2010, 11:47 PM   #2
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Sounds odd..

When you frame the shot, are you pushing the shutter button down halfway until it locks focus? Are you manually focusing? I find it strange that the camera would produce an out of focus shot if you are framing it and focusing correctly as you engage the shutter. Do out of focus shots appear to be in focus through your viewfinder?

Jason
08-22-2010, 11:48 PM   #3
hcc
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A few more info would help.

What lens did you use? Only the 2 kit lenses?

With AF.S or AF.C? Centre focus or multiple point focus?

If you use SR, did you wait 1-2 s for the SR confirmation?

I am not sure of the pb but trying to hint some possible cause.....
08-23-2010, 02:56 AM   #4
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QuoteOriginally posted by richardm Quote
Am I the only one? I love this camera when it does what it's supposed to do!
'it's supposed to do'?? You can't expect your camera to deliver 100% sharp, 100% in-focus photos, 100% of the time. That isn't going to happen with the K-x or any camera.

Think about some of the MANY things that have to come together to deliver a sharp, focussed image in a camera:

- minimal camera shake (operator induced, camera induced, environment induced)
- minimal subject movement (in 3D directions)
- appropriate shutter speed to deal with the above
- good lens optics (sharp high resolution lens, low CA, low flare etc)
- adequate depth of field provided by correct aperture and focal length settings
- good operator technique (1000 things here)

Also think about some of the things AF needs to be considered to work well:

- good light
- well defined high-contrast subject
- an identifiable priority AF subject that somehow matches the expectations of the user about what the camera should be focussing on

etc.

Also it would be useful to see some of those 2-4% failed images.

08-23-2010, 04:16 AM   #5
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I wish I had this problem, I only get random focused shots

Seriously: 2-4%? That's an extremely low number.
08-23-2010, 05:25 AM   #6
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QuoteOriginally posted by hcc Quote
A few more info would help.

What lens did you use? Only the 2 kit lenses?

With AF.S or AF.C? Centre focus or multiple point focus?

If you use SR, did you wait 1-2 s for the SR confirmation?

I am not sure of the pb but trying to hint some possible cause.....
Yes, the two kit lenses.

AF.C, center focus.

It's possible that I was too fast for the SR but again, I'm not seeing motion blur in these shots.
08-23-2010, 05:40 AM   #7
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maybe no motion blur due to high shutter speeds....which matters not if out of focus.

Post an example(s)?

Jason
08-23-2010, 06:02 AM   #8
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I would bet that it is the SR has not had time to stabilized.

richardm - For the photos that are not in focus, look at your EXIF data and check to see it the Shake Reduction was confirmed.

08-23-2010, 02:23 PM   #9
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With AF-C, the camera will happily let you take a shot even though nothing is currently in focus. That's more of a special=purpose mode for dealing with moving subjects, but normally, you should be using AF-S. In AF-S, the camera won't fire unless it has focused.
08-23-2010, 09:53 PM   #10
hcc
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QuoteOriginally posted by Marc Sabatella Quote
With AF-C, the camera will happily let you take a shot even though nothing is currently in focus. That's more of a special=purpose mode for dealing with moving subjects, but normally, you should be using AF-S. In AF-S, the camera won't fire unless it has focused.
+1
I agree with Marc.

Try with AF.S and wait for the SR icon light be on (1-2 s) before taking your shot.
08-23-2010, 11:07 PM   #11
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My bad... I meant to type AF.S -- I always use AF.S unless there's a compelling reason to switch. I'll see if I can dig up some example shots. I've probably deleted them all.
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