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07-23-2009, 10:20 AM   #16
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QuoteOriginally posted by ismaelg Quote
This could be a case like most aircraft accidents, where there is no single cause but a combination of causes.
Excellent analogy! And spot-on, I think.

QuoteOriginally posted by newarts Quote
Put the camera on a tripod or sit it on a stool or something so you are not holding it when a shot is taken - use the 2 or 10 second delay to shoot the photo. This will clarify if your holding technique is an issue.
Of course I neglected to suggest that... That's how I figured out my technique had slipped - I took some tripod shots for some reason and thought, "Hey, this lens isn't as crappy as I thought!" Then realised what that meant...

07-23-2009, 12:07 PM   #17
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I don't expect your images (if this is 100% crops) to be sharp using these lenses on such apertures.
I recently tested my new Tamron 70-300 from ebay on wide apertures and it is just very soft. Worse then my manual tele zoom at F3.5. And not comparable to extremely cheap Sigma 100-300mm or 55-200mm Pentax. According to reviews it must be defectuve, but I don't know.
Other Tamron on 2.8 must be definitely soft. Few zooms with f2.8 are sharp.
I suggest shooting small leafs, so you could tell focusing problems (use DEBUG menu to adjust if you need). I also suggest use manual focus for testing making many images with slight focus adjustment. And to see maximal sharpness you need tripod with 2s mirros lockup.
07-23-2009, 12:22 PM   #18
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Those suggesting it's because the lens is wide open are on drugs, it's far, far too soft to be that.

I suspect dud focussing (no real sharp areas anywhere though TBH) or a dud lens.
07-23-2009, 01:48 PM   #19
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QuoteOriginally posted by Alfisti Quote
Those suggesting it's because the lens is wide open are on drugs, it's far, far too soft to be that..
I'm pretty sure it is due to lack of performance wide open in combination with a generic and/or dirty filter.

07-23-2009, 01:54 PM   #20
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QuoteOriginally posted by Pål Jensen Quote
I'm pretty sure it is due to lack of performance wide open in combination with a generic and/or dirty filter.
I disagree, I have both lenses, the 28-75 is brutally sharp at f/2.8 at or close to 75mm, I would say pretty close to the FA 50 1.4 closed to 2.8.

Also the 70-300 is pretty sharp for it's price range even wide open. Sharper than the Pentax 50-200.
07-23-2009, 02:02 PM   #21
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I agree this has less to do with wide open softness as it has to do with an AF calibration problem with these lenses. At 100%, you wouldn't see any detail in these shots - they're just all OOF. Does this happen with all your lenses, Lori?

Has this just started happening? Anything different about your lenses?
07-23-2009, 02:26 PM   #22
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IMO, this has nothing to do with softness at f2.8 or the filter. These lenses are much sharper than this at f2.8. Even with a crack on the front element the pictures will be more clear, so you can safely rule out the filter.

You should send the lens and the camera to Pentax and have them sort it out.
07-23-2009, 02:36 PM   #23
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QuoteOriginally posted by pcarfan Quote
You should send the lens and the camera to Pentax and have them sort it out.
May I do the same? I'm also not statisfied with some of my shots

07-23-2009, 02:46 PM   #24
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The last time I got results like that it was because I had turned the autofocus off.
07-23-2009, 03:16 PM   #25
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If you're using the K10D, don't rule out the need to send it in for focus calibration with the lenses you use as it has many instances of less than accurate AF focusing. Test focus by focusing manually and compare it with an AF shot, set up the camera on a tripod and aim at a known object beforehand.

Ensure you don't jab the shutter release button but gentle squeeze it.
Check if you're actually holding the camera steady, something that can be the root cause of less than pin sharp images.

Did you inadvertently switch the AF focus point?
Did you wait until the SR hand icon in the viewfinder is off before releasing the shutter fully?
Did you mistake the red AF point indicator with the green AF focus confirmation light in the viewfinder when shooting?

Too many variables so it is best you slowly weed out the possibilities.
07-23-2009, 03:50 PM   #26
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QuoteOriginally posted by creampuff Quote
<snip>
Did you wait until the SR hand icon in the viewfinder is off before releasing the shutter fully?
<snip>
Too many variables so it is best you slowly weed out the possibilities.
This is very important. I've noticed several times if I jump the gun on the SR icon, I can get images that are blurry all over - nothing in focus. Even with my 35mm f2.8 Macro. It's like you catch it while it's locating itself.
07-23-2009, 05:41 PM   #27
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QuoteOriginally posted by creampuff Quote
Did you wait until the SR hand icon in the viewfinder is off before releasing the shutter fully?
I just checked out my K20 and even if I have it sitting on a tripod with just peeking through the viewfinder my hand icon stays lit all the time. I know I wasnt touching anything on the setup except lightly half pressing the shutter button which didnt transfer any movement to the camera.
07-24-2009, 08:55 AM   #28
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I have been getting similarly soft images from the SMC Pentax-M (manual) 50mm f2 lens I just picked up on ebay. It is VERY hard to get a sharp shot at the lower f stops. At f3.5 or f4, it is quite sharp, but focusing below that is hit or miss.

More often than not, my subject looks out-of-focus, not just un-sharp. I can practice the same f2 shot 10 times, and randomly get 2 shots that come out crisp and the others fuzzy. I use the AF indicator beep, but it doesn't seem very accurate. The crazy thing is that everything usually shows up good in the viewfinder, but the actual picture comes out blurry.

Is this just a problem with this lens? It's also weird that the focus ring turns REALLY FAR, almost 3 hand twists, but it seems like only about 20% of that range is focusable to me. I also find that at infinity, I'd like to go a little further to focus, but the focus ring is already maxed out. And sometimes in my blurry shots, I find that other areas in my shot are very crisp, but not the subject under my center focus point. Could this be front/rear focusing? If so, is there a way to fix/compensate?

But I have found a trick that works most of the time. I set my camera to auto focusing, which forces a focus lock before allowing the shutter to release, even though I'm manual focusing the lens. I found that if I hold down the shutter all the way, and VERY slowly focus the ring, it will trigger automatically when it first hits the AF point. Most of these shots are considerably clearer than those I try to do 100% manual at f2. However, this is only practical for portraits, you'll miss a lot of shots if used for action.
07-24-2009, 09:43 AM   #29
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It doesn't look OOF though because nothing looks in focus, something is REALLY wrong.
07-24-2009, 11:06 AM   #30
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Shirt in the last looks likes simple camera shake. Others aren't reproduced large enough to tell if its out of focus or shake. I guess the question is, do you *ever* get sharp pictures, or did something go wrong in these?
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