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11-22-2012, 08:24 AM   #1
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DA*200 on Q, quick test

Just a quick test this morning. My preliminary conclusion is that longitudinal chromatic aberrations (i.e., bokeh fringing) are a bit of a problem for this combo.

Test shots are with the 2-second self timer, camera resting on a bean bag, although not the most stable set up and you can see a bit of motion blur in one of the shots. My standard capture sharpening in RAW development, resized to 40% [edit: i.e., these are 40% crops] and re-sharpened. f/4, ISO 125, 1/80 second.

The first shot is back focused, the second one in focus, and the third front focused. The green fringing in the third shot isn't as evident as the purple fringing in the first shot, but it is there.

Attached Images
View Picture EXIF
PENTAX Q  Photo 
View Picture EXIF
PENTAX Q  Photo 
View Picture EXIF
PENTAX Q  Photo 

Last edited by baro-nite; 11-22-2012 at 05:06 PM. Reason: clarification
11-22-2012, 08:36 AM   #2
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Disappointing results. The bokeh is really ugly. I thought the DA*200 would be the ideal super-tele match for the Q.
Does f4 look better than f2.8?
11-22-2012, 09:04 AM   #3
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Haven't done a test at f/2.8 yet, knowing that LoCA is a bit worse wide open.

BTW I am a bit disappointed that the Pentax K->Q adapter doesn't report its aperture setting in EXIF, that I can find.

Edit: in fairness to the DA*200 bokeh, which I like very much on APS-C, this isn't the best background to test it.

Last edited by baro-nite; 11-22-2012 at 09:05 AM. Reason: addendum
11-22-2012, 09:30 AM   #4
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QuoteOriginally posted by baro-nite Quote
BTW I am a bit disappointed that the Pentax K->Q adapter doesn't report its aperture setting in EXIF, that I can find.
Disappointing and surprising. If you look in the metadata using a program that reports actual focal length and equivalent focal length, can you see both? I would think that would be available for use in SR.

11-22-2012, 03:20 PM   #5
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QuoteOriginally posted by audiobomber Quote
If you look in the metadata using a program that reports actual focal length and equivalent focal length, can you see both?
Yes, both there. But where f-number is reported it is 0, or where aperture value is reported (and different fields are recording depending on shooting mode, and perhaps lens?) it is 1.0, no matter the setting of the adapter's aperture ring.
11-22-2012, 03:31 PM   #6
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One question is am I pushing the cropping more than I should for such a test? My thinking is that the Q sensor gives us the benefit of a high-resolution crop to begin with, better (in at least some circumstances) than a similar digital crop on the K-5. But digitally cropping the Q file is maybe going too far? Here's the uncropped shot (#2, with sign in focus), resized for the web (25% of original size):
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PENTAX Q  Photo 
11-22-2012, 03:36 PM   #7
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You didn't say it was a crop. I think if you were to bump the contrast it would sharpen up quite a bit.
11-22-2012, 05:07 PM   #8
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QuoteOriginally posted by audiobomber Quote
You didn't say it was a crop.
Ah, sorry -- I've added a clarification that the first set are all 40% crops.

11-23-2012, 04:22 AM   #9
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The metadata will not show the aperture used with adapted lenses because the camera doesn't know it. There are no electrical contacts on the PK side of any adapter to pass the info to the camera. The best Pentax could do, in this situation, is report the position of their adapter. But 0 would be F1.8 on the 31ltd and F2.8 on the DFA100 macro.
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11-23-2012, 05:45 AM   #10
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QuoteOriginally posted by barondla Quote
The best Pentax could do, in this situation, is report the position of their adapter.
Right, I realize that. I just think it would be handy to have even that info in a custom EXIF field. For one thing, it is easy to turn the aperture ring without realizing it; it would be nice to have confirmation of what setting was used. Anyway, it is an extremely minor point and I'm very happy with the adapter so far.
11-23-2012, 05:45 AM   #11
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QuoteOriginally posted by barondla Quote
The metadata will not show the aperture used with adapted lenses because the camera doesn't know it. There are no electrical contacts on the PK side of any adapter to pass the info to the camera. The best Pentax could do, in this situation, is report the position of their adapter. But 0 would be F1.8 on the 31ltd and F2.8 on the DFA100 macro.
thanks
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I don't suppose apterture reporting matters that much anyway. I assume lens focal length needs to be entered manually and actual focal length for SR would be a calculated value. Do other makers' adapters allow SR too?
11-23-2012, 06:30 AM   #12
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QuoteOriginally posted by audiobomber Quote
I don't suppose apterture reporting matters that much anyway. I assume lens focal length needs to be entered manually and actual focal length for SR would be a calculated value. Do other makers' adapters allow SR too?
It matters to me, but I'm quite resigned to being too small a minority to get what I want. (And I don't expect to use K mount glass much on my Q, so in this instance it doesn't matter much even to me.)

But to answer your question, the SR works with any (or no) lens, just like on the K mount bodies.

And just because I'm stupid like this, I can't just leave "actual focal length for SR" alone. Certainly there needs to be some transform from focal length to sensitivity (scaling) of the motion sensor data. This has nothing to do with any "actual" focal length differing from the entered value though. (It's even sensor size invariant!)
11-23-2012, 10:22 AM   #13
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Thanks for doing the test Baronite. I had high hopes for the DA*200 based on the DA*300 experience.

I guess I will stick to the Sigma 70-200, it does not show any of the fringing problems and is similar to DA*300 in that respect.

It does need to be stopped down a couple of clicks before it gets sharpest. Thanks for helping save me money
11-23-2012, 10:39 AM   #14
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QuoteOriginally posted by crewl1 Quote
Thanks for helping save me money
You're welcome, although it has been rather more costly for me -- I just ordered the 60-250.
11-23-2012, 10:43 AM   #15
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QuoteOriginally posted by baro-nite Quote
You're welcome, although it has been rather more costly for me -- I just ordered the 60-250.
If you got the black friday deal then it will be worth it!!
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