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03-02-2016, 03:32 PM   #121
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QuoteOriginally posted by Winder Quote
He ordered the K-3II to test the pixel shift while he waits on the K-1 and the 31mm, but ended up testing the K-3 with the Sigma 35mm because the 31mm "Pentax 31/1.8 did not cut the mustard, so I used the Sigma 35/1.4".

Well, I read that, but I thought you had paid to read if this blogger's reasoning was valid or not.


Otherwise, I'm a bit mystified as to why you posted it.


Last edited by clackers; 03-02-2016 at 05:11 PM.
03-02-2016, 03:44 PM   #122
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QuoteOriginally posted by stevebrot Quote
Ummmmm...I am not confident that DA or D FA glass is any better...see below...



Yep. That is the opinion of several reputable reviewers out there. The UV and near-UV sensor bloom we call Purple Fringing is closely associated with LoCA and almost all lenses have some degree of LoCA if you test for it*. This is particularly true of fast primes at wide apertures.


Steve

* Some reviewers maintain the viewpoint that all lenses have some degree of LoCA and can be made to show PF with appropriate spectra composition.
I can tell you that the DFA 24-70 has almost no purple fringing (I have seen none to this point), while the DA *16-50, DA *200, FA 77, and FA 31 are all pretty prone to fringing. The DA *55 is not bad at all from that standpoint.
03-02-2016, 06:13 PM   #123
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QuoteOriginally posted by Oakland Rob Quote
Currently Adobe can process PS images; that's what I used in the photos I posted above. Fancy stuff like separating the four frames requires command line work with a special variant of dcraw, although maybe some applications that use that have incorporated PS support; I dunno.
I think it would need to be more like 5 frames - the four sensor readouts plus a frame-map detailing which pixels composite and which do not. If the frame-map could be manipulated as if it was a mask, a lot of options could open up. Especially if one could specify which source-frame to use, not just an 'all' or 'one' but 'here use the first two' and 'there use the first and last' and 'overthatway use frames 1, 2 -and- 3 but not 4'. That kind of thing should be comparatively simple to implement in a raw-processor; it's just a specialized layer handler. If it was approached that way - so the PS raw file is more like a container for the 4 base raw files plus the mask-map, then it should also be possible to process each of the base files individually. It would also be possible for software to auto-create an alternative mask-map with adjusted parameters regarding movement, etc. It was mentioned that the movement compensation was on/off - imagine having it as a dynamic slider so you could apply just enough to avoid artifacts and no more. The flexibility would seem to be maximized with this strategy.

I'm looking at it as a computer programmer, though, not a photographer - I have comparatively minuscule experience in PP.
03-03-2016, 12:50 PM   #124
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QuoteOriginally posted by clackers Quote
I thought you had paid to read if this blogger's reasoning was valid or not.
That is my main issue with Lloyd Chambers. His posts are legit and very useful, but I am not willing to pay his hefty subscription cost for the benefit of his knowledge.


Steve

(...would really like to see the full version of his PF testing using tuned spectrum LED lighting...)

03-03-2016, 01:23 PM   #125
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QuoteOriginally posted by jyndi Quote
I think it would need to be more like 5 frames - the four sensor readouts plus a frame-map detailing which pixels composite and which do not.
QuoteOriginally posted by jyndi Quote
I'm looking at it as a computer programmer, though, not a photographer
You don't need five frames to deconstruct or describe the image, just the base image (exposure #1), its three siblings, and the pixel replacement metadata. My understanding is that the base image serves as the default for the motion mending substitution and is the source for the replacement pixel values. It is also my understanding that the motion mending is applied by detection during RAW processing and is not a capture-time calculation. As such, I would expect that whatever version of PDCU ships with the K-1* and (eventually) ACR will support that feature. What would be cool is if PDCU and/or ACR would allow active modification of the substitution during PP.


Steve

* There is good evidence that the code for in-camera JPEG and TIFF processing from RAW is common to or derived from that used by PDCU. This has been the case since at least the K10D.
03-03-2016, 03:08 PM   #126
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About 18 minutes into this youtube presentation by RICOH (unfortunately in Japanese, maybe someone could translate?) they show some examples of PS and, I guess, describes a little about the motion correction function.

A picture from an ice skating rink with lots of movement seems to be nicely handled, and, can you believe it, a small waterfall. Looks very promising.

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