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05-14-2008, 08:46 AM   #1
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Is my DA14 lens in need of calibration?

I took a number of pictures using my DA14 and recently a friend saw the pictures and commented that the pictures are not sharp. After examining them at 100% crop, I cannot say I disagree with him.

I would like to know your comments and opinions. Do I need to send my DA14 for calibration? What is fundamentally wrong? my skills or my equipment?

I have posted the original photos (full 6MP) here.

Thanks!

05-14-2008, 08:56 AM   #2
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Ouch. The kit lens is sharper than your copy.
05-14-2008, 08:59 AM   #3
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what is wrong with the lens??
05-14-2008, 09:58 AM   #4
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What if you use F5.6-8 instead of 9.5?

I have the 14 too and it's a bit better than this, but really wide lenses won't generally compare favourably to others.

Also, try manual focusing so that the right edge of the infinity symbol is lined up with the line, and then use F/8. I find the AF on mine tends to backfocus.

05-14-2008, 10:13 AM   #5
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That photo is with f9?! the CA on the trees are crazy... i thought it was shooted at wide open...
05-14-2008, 11:53 AM   #6
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the lens is ok but the shutter speed is a little bit lo 1/20
so as you kan see on your exif

Exif Sub IFD

* Exposure Time (1 / Shutter Speed) = 1/20 second = 0.05 second
* Lens F-Number/F-Stop = 95/10 = F9.5
* ISO Speed Ratings = 200
* Original Date/Time = 2007:12:27 10:39:14
* Flash = n/a (8)
* Focal Length = 14/1 mm = 14 mm
* Image Width = 3008 pixels
* Image Height = 2008 pixels
I think it is movement unsharpnes
05-14-2008, 01:10 PM   #7
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I don't have this lens but the level of details matches my DS. I think this is how much the Pentax 6MP can deliver.
05-14-2008, 03:04 PM   #8
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Hard to judge as the images are resized instead of being original crop.

Da 14 is sharper than da* 16-50 in the corners. Otherwise, little difference stopping down between the two.

05-14-2008, 04:41 PM   #9
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The photos are all taken using tripods. Should shutter speed matters then?

What I observed is that the IQ is not sharp at all. It is like there are a lot of tiny tiny grains which make the image look well....flat. Is this what they call, failure to focus at infinity?

roentarre, you can click on the "original size" in flickr to view the original version without cripped.

I will send my lens back to pentax today and see what they say.
05-14-2008, 04:46 PM   #10
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QuoteOriginally posted by jslifoaw Quote
What if you use F5.6-8 instead of 9.5?

I have the 14 too and it's a bit better than this, but really wide lenses won't generally compare favourably to others.

Also, try manual focusing so that the right edge of the infinity symbol is lined up with the line, and then use F/8. I find the AF on mine tends to backfocus.
I used F5.6 to F8 before on other images (not yet posted to flickr), but generally the results are similar. I just thought when I am on landscape mode, I should be stopping down to get more depth of field and to get everything else in focus. But somehow i think my DA14 is not able to do this.
05-15-2008, 05:59 AM   #11
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I sent the lens and my k100D to pentax for a checkup this morning but the technical manager, after firing a few shots, some using AF and some using MF, feels that there is nothing fundamentally wrong with the combo. He is, however, kind enuf to help me calibrate/fine tune the camera body with respect to the DA14 lens. The whole process take about 30mins.

I will test the lens this coming weekend to see how things go.
05-15-2008, 06:05 AM   #12
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Let us know how it goes after
05-16-2008, 10:23 PM   #13
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QuoteOriginally posted by vizjerei Quote
Let us know how it goes after
Thanks for your concern.

The calibration does seem to help (slightly perhaps). I have posted one of the test shot here.

I spoke to a photographer friend and he said that ultra-wide lenses having a 90deg. field of view (like the DA14) can never be sharp especially at the corners. Also, it is not usual to pixel peep into images taken with ultra-wide lenses and we can never expect the 100% crop image to be as sharp as those taken with a zoom lens.

Nevertheless, I have posted the 100% crop of the test shot here for information.

Attachment 12332

Last edited by raider; 01-11-2009 at 09:03 PM.
05-16-2008, 11:49 PM   #14
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Well, considering the low pixel dimensions of the 100% crop image here, this doesn't look too bad at all. Good detail is visible in the lower corners, the tree, and the overhead wires. The full image you posted on the flickr site looks just fine as well. Monterey Bay?
05-16-2008, 11:58 PM   #15
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Generally primes are sharper at given length and f-stop than zooms – that's one reason to get them.
The DA 14 may be a little soft. I have both the 12-24 and the 14 and it seems the 12-24 beats the 14 at f4. The niche for the prime then is when you want a lens as fast and small as possible. For landscape and other daylight shots then a zoom with a smaller aperture might be better.
Somewhat disappointingly I'm getting more focus misses with the 14 mm than with the zoom, especially at very close range.

Looking at tree branches against the sky in the corner of a picture at 100 % is just about always depressing. But in real world usage that's what you never do. I think your pictures both "before" and "after" are good enough for all practical purposes.

Perceived sharpness is something that pops out when contrasted with blur. Take a few shots wide open with some well focused eyelashes in the middle and you'll see.

The grainy appearance mentioned somewhere is due to sharpening and jpeg-compression made to the pictures either in the camera or pp.
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