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07-12-2012, 05:59 AM   #1
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Is this chromatic aberration normal for DA 14mm

Just got a new DA 14mm and I was checking it out and ran into a problem and I wanted to see if anyone else who had copy of this lens had this issue. I started to get bad chromatic aberration when the lens is wide open. I took some test shots inside to eliminate other variables and this is what came out. You will notice that in the center of the first picture the test grid is Navy blue (it should be black) on second picture the test grid is black (just like it suppose to be). I tried this with different light, with flash and with natural light, it didn't make a difference. So is this normal, or do I just have a bad copy.


Last edited by photomission; 12-11-2012 at 05:43 PM.
07-12-2012, 06:15 AM   #2
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Crops?
07-12-2012, 06:38 AM   #3
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Without cropping

Yes, here is the full frame

Last edited by photomission; 12-11-2012 at 05:43 PM.
07-12-2012, 06:51 AM   #4
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Wish I could help but i don't own a test chart to test mine (which is a very early copy) I haven't noticed any massive CA in normal shooting with the DA14 though
OTOH I'm just as likely to shoot for b/w so it wouldn't impact me.

Photozone reported moderate CA and PF withing the norm for this type of lens

http://www.photozone.de/pentax/117-pentax-smc-da-14mm-f28-ed-if-review--test-report?start=1

07-12-2012, 07:09 AM   #5
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I notice a little CA from the DA 14mm, but I don't think it's terrible. It cleans up quickly in LR4, too. Additionally, I don't shoot the DA 14mm wide open too much. I'm usually in the f5.6-f11 range with some shots at f4 or f16 if I need it. I think that's partially because the lens is a little weak at f2.8, and partially because the stuff I shoot at 14mm usually requires me to stop down for DOF reasons.
07-12-2012, 07:14 AM   #6
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Your right about the other reviews

I read the reviews and that's why I don't understand. I guess the question is does the 14mm exhibit slight CA or bad CA wide open?
07-12-2012, 07:17 AM   #7
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It does clean up once you stop down

On the second shot I took it at F4 and the colors are all back to normal. The center grid is black.
07-12-2012, 07:22 AM   #8
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I have to admit I don't shoot it wide open very often, usually i'm around 5.6-8 If I'm shooting wide open it's usually in a club in really low light so CA is the least of my concern then.
Sorry I couldn't be of more help. If I get a chance i'll try some tests to see if I have the issue.

07-12-2012, 06:00 PM   #9
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The 1st shot is OOF, that's why.
07-12-2012, 06:37 PM   #10
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I think I have to disagree

I mentioned that I had taken the same shot numinous times under different lighting conditions. Attached is a different example of one of the other times with a closer crop of the center grid. I can understand once or twice being out of focus but all 9 times being out is a little hard to believe. This crop really shows the color variation with in the grid. I will take another one in a few minutes, just to make sure.

Last edited by photomission; 12-11-2012 at 05:43 PM.
07-12-2012, 07:12 PM   #11
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It is OOF w/o question, and quite possible BF according to my experience. I believe it was deliberately to due to severe field curvature of this poorly design optics. I have described the problem in my review.
07-12-2012, 07:27 PM   #12
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Link?

Do you have the link to the review handy. thanks
07-12-2012, 07:37 PM   #13
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Never mind found it

I tried the links on the review but they are no longer active. Can you PM me the PNG diagram?
07-12-2012, 07:41 PM   #14
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You may check out the detail of this lens here:
http://translate.google.com/translate?u=http%3A%2F%2Fpentaxstudy.bufsiz.jp%2FLensdesign%2FDA14%2FDA14_Design.htm&hl=en&langpair=auto|en&tbb=1&ie=Shift_JIS

You can tell why the lens was optimized to BF from FIG.4 because when the centre is in focus, the edges will be way OOF even stopped down to f11. IMO, this lens in great for snaps but hopeless for scenery because even sharpness across the frame is impossible.

Last edited by wlachan; 07-12-2012 at 07:48 PM.
07-12-2012, 07:51 PM   #15
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It is definitely out of focus and navy. I don't have the DA 14, so i can't compare that exact lens, but it is my experience that any super wide tends to product at least some CA, especially wide open. Perhaps I don't expect enough from my super wides when they are wide open in terms of CA. I would be more concerned on the focus. Of course, lenses get sharper when stopped down, but I would be messing about trying to get the sharpness just right.
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