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07-16-2011, 12:06 PM   #1
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DFA 100mm WR advice sought

I purchased a new DFA 100mm WR. I notice a large amount of purple fringing, shooting wide open, even in the center. Here are the pictures - The original, full sized picture with the DFA 100mm WR, a 100% crop of the center (bad fringing!) and a 100% crop of the same subject with the DA 70mm Limited. These are all at f/2.8.

When the DFA 100 is stopped down to f/5.6, the fringing is much reduced.

Can anyone with the DFA 100mm WR comment on this? Much appreciated. I can still return the lens.

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07-16-2011, 12:45 PM   #2
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Were those taken with a hood?
07-16-2011, 02:26 PM   #3
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Yes, both the 100mm and 70mm had hoods.
07-17-2011, 07:18 PM   #4
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I've never run into such fringing issues with my DFA 100; but then again, I rarely shoot anything (let alone white objects!) in bright, garish sunlight with it. I really don't see this as being a big deal. No lens is perfect; and if the worst you can say of a lens is that it fringes purple when shooting white objects in bright sunlight wide open, then it's probably a pretty good lens. I suspect that every lens I own would fringe if I threw that kind of light at it.

I wouldn't return the lens unless I didn't like it for other reasons or it had some genuinely non-trivial issues.

07-18-2011, 08:30 AM   #5
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QuoteOriginally posted by northcoastgreg Quote
I've never run into such fringing issues with my DFA 100; but then again, I rarely shoot anything (let alone white objects!) in bright, garish sunlight with it. I really don't see this as being a big deal. No lens is perfect; and if the worst you can say of a lens is that it fringes purple when shooting white objects in bright sunlight wide open, then it's probably a pretty good lens. I suspect that every lens I own would fringe if I threw that kind of light at it.

I wouldn't return the lens unless I didn't like it for other reasons or it had some genuinely non-trivial issues.
Thanks for looking, and I appreciate your comments.

I took the same photo with four other lenses I have that are remotely close to 100mm, all wide open. There is very little or no fringing in any of them, especially right in the center of the picture. Even the lowly DA50-200 displayed very little fringing at 100mm, wide open, near the center of the picture.

My only conclusion is the lens is defective. I'll get a replacement instead of a return, and hope another copy is better. The lens is razor sharp though, and I really like the focal length for macro stuff...
07-18-2011, 08:57 AM   #6
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I doubt the replacement will be better.
07-18-2011, 10:16 AM   #7
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QuoteOriginally posted by Aegon Quote
I doubt the replacement will be better.
I agree- that looks about the same as my DFA 100mm (non-WR) wide open at edges of extreme contrast. The areas with the bad fringing have one or two channels clipped, this seems to bring out the worst of it (actually the only time I've ever seen it).

It's pretty much a non-issue for me, but if it's a deal breaker for you (leadfoot), a return is probably in order and not a replacement imo.
07-18-2011, 11:15 AM   #8
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I'm not seeing that on my copy, must be lucky.
Exif doesnt show, but I just now shot this at f2.8 100 ISO, in camera JPEG


Last edited by crewl1; 11-25-2013 at 10:31 AM.
07-18-2011, 07:17 PM   #9
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Thanks for the comments. I returned the lens.

This was the first Pentax lens I was disappointed in - no other Pentax lens even came close to such nasty fringing. It is a pretty harsh test, and apparently it's an old optical design, but no lens should look like that in my opinion. I'll bet it was a bad copy, but I don't have time over the next couple of weeks to muck around getting it replaced...

Again, thanks!
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