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Author Topic: Four raw converters , handling demosaic errors  (Read 21134 times)

ErikKaffehr

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Re: Four raw converters , handling demosaic errors
« Reply #40 on: November 03, 2014, 01:20:25 pm »

Hi,

My focus here is on demosaic artefacts and not about colour. But, I did an empirical test on colour rendition using an IT 7 target here. What I have found here was using Lightroom with a camera specific colour profile for the P45+ was more accurate than Capture One used with the "Film curve" using linear, C1 was a bit more accurate than Lightroom. The Sony SLT 99 was most accurate, however.


A problem with this tests is that the Delta E calculation does include lightness, which is affected by tone curve.

One interesting observation in this test that some blue colours had extreme errors in Capture One, but those were not visible on screen, depending on the limited gamut of the computer screen. So I have DeltaE = 17 but is not visible on screen, because of gamut lmitation. The same difference may be very much visible in print!

Best regards
Erik
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torger

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Re: Four raw converters , handling demosaic errors
« Reply #41 on: November 03, 2014, 01:31:47 pm »

Aliasing is a very interesting aspect of image quality, as a "defect" (lack of aa filter) has been turned into a feature. No matter what people say, photographers love to pixel peep for sharpness. "Improved micro contrast" has been the reason to not have AA filter. Noone seems to care about glaring color aliasing or even moire, although it's a much more severe image quality problem than any lack of micro contrast.

It's some sort of psychology (and perhaps great sales work too), and I can't say I'm unaffected by it myself. Would I want an AA filter on my MF sensor? Uhmm... probably, image quality would improve, especially for large prints where color aliasing in details can be visible -- but I rather want more megapixels and blur away the aliasing with diffraction. I'm a landscape photographer and shoot at small apertures so it can work out, but I find it fascinating that professional portrait photographers who shoot at large aperture seems to think that being without an AA filter is a feature rather than the bug it really is.
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Fine_Art

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Re: Four raw converters , handling demosaic errors
« Reply #42 on: November 04, 2014, 02:24:11 pm »

Attached 2 200% screenshots from Raw Therapee. I tried to upload a 3mb crop of the same cranes which failed, probably from size despite the stated 4mb limit.

1 100% screenshot of the people fro looking at color. RT does not have an .IIQ profile so I had to play with the colors a bit. It was still fairly easy with a few lab curves. The default import had the guy looking red in the face which needed to be fixed.

I expect the lanczos uprezing would probably be better to tif than the screenshot to MS paint. It still looks decent.
Nice technique on the DoF capture in the shot.
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Fine_Art

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Re: Four raw converters , handling demosaic errors
« Reply #43 on: November 04, 2014, 02:28:10 pm »

3rd shot which failed last post.
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ErikKaffehr

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Re: Four raw converters , handling demosaic errors
« Reply #44 on: November 04, 2014, 03:07:29 pm »

Hi,

This is the DCP I use with the P45+: http://echophoto.dnsalias.net/ekr/Articles/RawConverters/Profiles/P45+DI131225_studio.dcp
Best regards
Erik




1 100% screenshot of the people fro looking at color. RT does not have an .IIQ profile so I had to play with the colors a bit. It was still fairly easy with a few lab curves. The default import had the guy looking red in the face which needed to be fixed.

« Last Edit: November 04, 2014, 03:20:36 pm by ErikKaffehr »
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Fine_Art

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Re: Four raw converters , handling demosaic errors
« Reply #45 on: November 04, 2014, 03:19:00 pm »

Forgot the link.
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ErikKaffehr

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