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02-27-2011, 11:11 AM   #16
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Generally newer lenses designed for digital tend to be better with chromatic aberration than film lenses. Photozone.de and Cameralabs.com give CA scores for lenses.

Fixing chromatic aberration in post is not that difficult. Many programs have some built in capacity for this at least Adobe ones and Aperture do. If you run into the situation a lot, PTLens is a $25 Photoshop/Elements plugin that will automatically fix CA as well as lens distortion. I use this often. For a more sophisticated fix, DXO Labs software can do great stuff with files that would otherwise be unusable.

02-27-2011, 11:43 AM   #17
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Thank you for posting an example.

I've really not had an issue with any of the DA limited series I have (15, 21, 40mm) with PF.
For DA zooms, I have used the in-camera correction to good effect for removal (shoot jpg, or raw and process in-camera, or take advantage of the latest version of Pentax Digital camera utility to remove them).

As you have the K-5, I would use these as the JPG settings. Unfortunately the 77mm is coated in pixie dust, but that dust isn't coated....
02-27-2011, 07:35 PM   #18
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The 77 predates digital cameras by several years. I don't think it is any more prone to CA than other lenses, but it does seem prone to purple fringing.
My understanding is that PF has somewhat to do with the sensor as the lens, and some combinations are more prone to PF than others.
One of the things we have to do as photographers is play to the strengths of our equipment if we want to have successful pictures.
You have found a scene type that your 77 doesn't handle well, so generally you ill want to stay away from that type of picture.
The 77 does handle many other scene types admirably well though.
02-27-2011, 11:55 PM   #19
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Thanks to all who responded to my questions. Much appreciated!

02-28-2011, 03:03 AM   #20
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QuoteOriginally posted by Wheatfield Quote
My understanding is that PF has somewhat to do with the sensor as the lens, and some combinations are more prone to PF than others.
I am not too sure if this is more sensor related problem than lens related, coz I am just going through some old photos taken with my Zenit 11 and Helios 44-2 and guess what - there is a lot of PF in situations like OP`s pic, but it is never so bad
I`d say that Isucadien`s pic is showing really high level of longitudal chromatic aberration-bokeh fringing, which is probably "inherited" in the optical construction of FA 77 ltd and it is typical situation where true APO lenses would show none
it is hard to estimate the influence of sensor construction but probably the AA filter has got some to do with it? I don`t know

Last edited by stanic; 02-28-2011 at 06:13 AM.
02-28-2011, 05:52 AM   #21
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QuoteOriginally posted by yucatanPentax Quote
Are there lenses which handle this situation without creating purple fringe? Lenses that can take sharp focus super high contrast and do not fringe or display CA?
The newer DA limiteds will be better, apart from that it's hard to bea an FA limited at any time...
02-28-2011, 07:01 AM   #22
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I use all older lenses, but I've found some tend to purple fringe more than others. I have a Rokinon 75-300 that I never use any more because of it, Lentar 90-230 (M42 screw mount) that does fairly well, and my Sears 80-200 does a great job.

Recent picture similar to yours with the Sears cropped at 1280x960



This same picture with the Rokinon would be loaded with purple fringe and unusable.

I also find that underexposing helps a lot.
02-28-2011, 07:21 AM   #23
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QuoteOriginally posted by yucatanPentax Quote
Q from someone who seriously doesn't know the answer:

Are there lenses which handle this situation without creating purple fringe? Lenses that can take sharp focus super high contrast and do not fringe or display CA?

Inquiring minds want to know! :-)
let's make sure you call the issue what it is. This is NOT purple fringing, but lateral CA, which is common at some level in almost every lens.
QuoteOriginally posted by stanic Quote
hmm, probably some apochromatic lens?
anyway, FA ltd`s really create more PF than, say DA ltd`s
yes, Aprochromatic lenses attempt to get this resoplved, but no lens is perfect. The image shown is a 100% crop and these will usually show some CAif you look for it. THe blown out highlight background is the worst for showing CA but not the only time, it is just much more obvious when the background is white.

02-28-2011, 07:24 AM   #24
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QuoteOriginally posted by Lowell Goudge Quote
This is NOT purple fringing, but lateral CA
longitudal CA maybe? (from the front to the back I mean)
02-28-2011, 08:11 AM   #25
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QuoteOriginally posted by stanic Quote
longitudal CA maybe? (from the front to the back I mean)
My Bad

Yes longitudinal.

purple in front, green behind the plane of focus.
02-28-2011, 08:24 AM   #26
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If you try hard enough, you will find it... no matter what lens you use.
02-28-2011, 10:55 AM   #27
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QuoteOriginally posted by Chex Quote
From what I've seen most primes are better off than zooms, the new 55mm f1.4 shows good CA control wide open compared to others.

I've noticed the same thing. Focal length also seems to play an important role, with normal range lenses having the best control and ultra wide angles the worst. My DA 10-17 produces purple fringing so wide and bright that sometimes I can see it in the viewfinder. The DA 12-24, while not nearly as bad, also has its share of issues. But I've rarely run into CA issues with my A 35-105, and have yet to run into such issues with the M 50/1.7.
02-28-2011, 02:00 PM   #28
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I've never seen any fringing with my Sigma 17-70 f2.8-4.5 or my Pentax 50-200 kit. All my primes have some and as for the Tamron 70-300 it's the very definition of PF.
03-07-2011, 07:46 PM   #29
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took very similar shot today...

very similar situation with a bird and I got the same results!
I was trying out my new M 80-200mm lens.
glad I found this post.
03-08-2011, 12:47 AM   #30
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Adobe Photoshop and Camera RAW and even Pentax's Silkypix can take care of it PP with a little messing around.
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