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01-04-2011, 08:50 AM   #16
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I find quite a bit of PF from my DA55-300 with the K5. It's strange as I never noticed PF with my K20d with the same lens.

Seems to be mostly on the edge of snow on a sunny day... no pixel peeping needed it's quite apparent:





Pat

01-04-2011, 02:53 PM   #17
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Everyone needs to have a least one raw converter than can handle purple fringing. Capture One and DxO are two programs that can.

Rob
01-05-2011, 06:18 AM   #18
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I've not noticed nor can find any pic with that much PF/CA from my DA55-300mm/K20D as well. Now there is some not much but a tiny bit if you pixel-peep of PF with the K20D, and for sure some CA just less; the DA55-300mm has mainly the blue/green type CA. Yes it's true the K-5 has higher resolution but really not much more than the K20D. As the K20D is a 14.6mp dSLR versus 16.3mp, 1.7mp more. Thats not enough pixels to explain the amount of PF seen.


I want to say so your not constantly looking and wondering about the PF situation that I looked at all your posted pics (Smugmug). If the posted pics represent the worst case than your OK, not a problem IMHO. If I bought the K-5 and that was worst case I would be happy. Now if all the pics you posted showed strong PF/CA I would be waiting for the K-?.


Last edited by jamesm007; 01-06-2011 at 05:53 AM. Reason: add pic
01-05-2011, 05:28 PM   #19
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QuoteOriginally posted by gazonk Quote
AOL! Funny thing is, I never noticed it on film. Is this color of a wavelength that film is quite insensitive to, or is something else going on?
From what I understand, purple fringing a sensor-based problem, in never occurred on film. Something to do with photons leaking from some of the pixels to their neighbor pixels, but not completely sure.

01-05-2011, 05:57 PM - 1 Like   #20
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QuoteOriginally posted by VaSA Quote
From what I understand, purple fringing a sensor-based problem, in never occurred on film. Something to do with photons leaking from some of the pixels to their neighbor pixels, but not completely sure.
PF is bokeh CA and exists for film too. It's just more appearant with high pixel densities and high dynamic range. Film actually has much worse problems at blooming highlight boundaries like reflections from the separate emulsion layers...

There could be a scenario where the K-5 actually amplifies PF beyond the level to be expected from its high DR and high pixel density. But there was not a single photo in this thread hinting in that direction and nobody cared to do a controlled test anyway...

The PF issue you are mentioning is confined to CCD sensors (as opposed to CMOS) and a few ill- designed sensors in the early ages of digital photography. Not applicable here.
01-06-2011, 04:10 AM - 1 Like   #21
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What VaSA calls PF is actually called blooming, and is, as falconeye says, a non-issue nowdays.

It is my understanding that PF is caused by uncorrected IV/UV wavelenths of the lens and a capturing device which is sensitive to those wavelengths. If this is the case, then different IR filter and different CFA could emphasize PF on some cameras over others. On the other hand, maybe my hypothesis on this is wrong

Bokeh CA in my understanding is simply loCA and it manifests itself differently. Again, I may be wrong - actually, I am not sure if "bokeh CA" has even been properly defined anywhere.
01-06-2011, 09:19 AM   #22
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QuoteOriginally posted by jamesm007 Quote
I want to say so your not constantly looking and wondering about the PF situation that I looked at all your posted pics (Smugmug). If the posted pics represent the worst case than your OK, not a problem IMHO.
Thanks for looking and I agree, I am OK! As I mentioned in a post earlier the PF only appears with a specific lens and in very specific conditions (snow+sunny+high contrast+back-lighting), so I would not consider it to be a problem at all.

I've known since the day I bought the 55-300 that it had a slight tendency to PF in hard conditions. It just shows a bit more on my K5d than on my K20d and K100d.

Pat
01-06-2011, 01:05 PM   #23
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look at the PF everywhere!


01-06-2011, 05:00 PM   #24
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any of you guys have a Tamron 70-300? That PF'd a crapload on the K10D but less on the K20D. Would be interesting to see how much it glows on the K-5 :-)
01-06-2011, 06:54 PM   #25
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What lens was this shot with? The DA*16-50mm, DA*200mm, DA*50mm all have fairly strong PF/CA at the right setting... so what does this pic show. Do you have another dSLR to compare with? Lots of questions. So I thank you for the example and what you are showing. BTW do you consider it a problem or a nuisance?

I can remove most CA and PF. The reason I don't like it (and why I like Sigma lens) is high PF/CA can and does hurt micro-contrast. A quality hard to describe but is very real and noticeable without pixel-peeping. Look below. The lens aberations even if removed what will there? The lens did not capture any detail behind the aberations (PF)!


01-06-2011, 08:21 PM   #26
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James, the picture was shot with da* 16--50.

I just noticed that I shot the same scene with the k-7 and da* 16--50 in November, almost under the same level of sunlight, at a different angle though. Surprisingly, what I just found is that the k-7 also produced considerable amount of PF, actually on par with the K-5...

So I don't know if the k-5 amplify PF... at least from my samples.

QuoteOriginally posted by jamesm007 Quote
What lens was this shot with? The DA*16-50mm, DA*200mm, DA*50mm all have fairly strong PF/CA at the right setting... so what does this pic show. Do you have another dSLR to compare with? Lots of questions. So I thank you for the example and what you are showing. BTW do you consider it a problem or a nuisance?

I can remove most CA and PF. The reason I don't like it (and why I like Sigma lens) is high PF/CA can and does hurt micro-contrast. A quality hard to describe but is very real and noticeable without pixel-peeping. Look below. The lens aberations even if removed what will there? The lens did not capture any detail behind the aberations (PF)!

01-07-2011, 07:49 AM   #27
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QuoteOriginally posted by shang Quote
look at the PF everywhere!
That's not PF, it's lateral CA. Note that there is "purple" on one side of the highlights and a "greenish" color on the other side. This is very easy to fix using the chromatic aberration tools in programs such as Photoshop. PF is a different problem. Not only do you not have "PF everywhere", I don't see any PF in your image.

I don't believe that anyone is suggesting that lateral CA is worse with the K-5 than with the K-7. The issue has to do with purple fringing, which is a different phenomenon.

Dan

Last edited by Dan; 01-07-2011 at 10:05 AM.
01-07-2011, 01:48 PM   #28
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QuoteOriginally posted by falconeye Quote
PF is bokeh CA and exists for film too. It's just more appearant with high pixel densities and high dynamic range. Film actually has much worse problems at blooming highlight boundaries like reflections from the separate emulsion layers...

There could be a scenario where the K-5 actually amplifies PF beyond the level to be expected from its high DR and high pixel density. But there was not a single photo in this thread hinting in that direction and nobody cared to do a controlled test anyway...

The PF issue you are mentioning is confined to CCD sensors (as opposed to CMOS) and a few ill- designed sensors in the early ages of digital photography. Not applicable here.
Thanks for pointing that out to me
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