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01-22-2019, 04:56 PM   #1
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Image Compression / Banding issues [Fixed]

Hello, it's been a while since I've been here.

Schools kept me from shooting, and now that it's getting really busy I'm feeling the need to get out more (typical.. but also quite logical I'd say!).

I've had this issue for a few months now but never really took the time to look into it exactly, except that with the photos I've taken today it seems extremely pronounced.

Frequently I'm getting gray (with some cyan and pink) banding when viewing my photos on the PC, I figured this was down to something with my ICC profile/monitor, but after re-calibrating (and resetting the colour options to 0-255 in the nvidia control panel - thanks nvidia for resetting it all the time!) it persisted.

I visited a forest today and most of my images have some portion of grey mush in it which does kinda clear up when I lower or raise the EV by >1.5.
I'm not sure if this has something to do with the K-1, but I'm not getting it from the K-50 I fear, at least nowhere as pronounced!

Here's little example:









These bands (with or without colour) stay even if I desaturate the whole image to b/w for some reason.

I it's far less pronounced after exporting, so I'm thinking it might have something to do with filesize? Or a camera limitation? Can't quite wrap my head around it.
I'd be happy to know if there's a way around it, I'm finding it increasingly annoying when trying to edit images as you might understand...

Thanks!


Last edited by Topsy; 01-23-2019 at 06:06 PM.
01-22-2019, 05:51 PM   #2
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On my calibrated display it appears to be a processing artefact - not from the camera, but from the software processing the raw files. It looks like the highlights are being pulled, and the shadows lifted causing the midtone to dominate which results in this "mush". Have you tried resetting all the image tone controls to default?


Also banding can and will occur when the changing from 16bit to 8 bit - also drastic changes in colour space can cause banding due to limitations in the output spaces colour gamut.
01-22-2019, 06:20 PM   #3
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As far as I'm aware all image tone controls are on default in both programmes, I'm not even sure how I'd change it in Capture One.
Colour space hasn't been changed either and 16bit is selected.

Camera is set to DNG and sRGB.

Here's another one.. (that's about half the frame 33% magnification)


Funnily enough I was having a conversation about how some photos appear to look better on the camera than on the PC as I shot that. hah.

Definitely looks absolutely okay in the camera so the probably should be able to be solved somehow!
01-23-2019, 03:00 AM   #4
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That looks rather like the effect you'd get by lifting the lower left edge of the tone curve up considerably (effectively dragging everything below that level up).

Would you be able to post a DNG on Dropbox (or something similar)? If you can, I'd be happy to take a look at it in darktable and RawTherapee. Both use different raw converters, and both have profiles for the K-1, so they would give useful comparisons.

01-23-2019, 02:36 PM   #5
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What you are illustrating is the different default tone curves of ACR and Capture One. Each company has differing tone curves for camera bodies - i.e. sensors basically.

Since I do not use Adobe stuff anymore, you might enlighten us as to which version of ACR is being used. As for Capture One the difference between v10 and the current v12 are pretty substantial. You can change the tone curve in Capture One in the "Basic Settings" tool in the Color tab. Also in Capture One in "Basic Settings" you can choose "linear response" which removes all default tone curves (as determined by the Phase One engineers) from the RAW file. I do not know how to do the same in ACR (which I do not use although I still have LR 6.14) or Affinity Photo (which I use for things like panoramas and adding text to images).

You might want to play around with the "linear response" tone curve. It uses the data off of the sensor without preconceived tone curves. The image will look extremely flat and bland but you will be able to push your post processing to what you desire.

Trying to get the "identical look" out of two different RAW converters is bound for overall failure. The differing companies have cooked in their demosaic algorithms, noise adjustments, sharpening and color interpretations. They will not ever be "the same". When I was taking a seminar in backups and PCNW (Photo Center North West) I stated that I used both LR and CO. I was asked why do you use both? My answer was that I used LR when I wanted to have the default "look" be more like the Kodak-chromes and I used CO to have the default "look" be like Fujichrome (The Pentax software looks to me like Agfa - never really liked Agfa all that much). But truth be told, I changed the Kodak/Fuji moniker depending on the time of day. They just look different, there is no "truth" or absolute correct way to process images.

Last edited by PDL; 01-23-2019 at 02:38 PM. Reason: subtle and not so subtle stuff.
01-23-2019, 02:37 PM   #6
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QuoteOriginally posted by BigMackCam Quote
That looks rather like the effect you'd get by lifting the lower left edge of the tone curve up considerably (effectively dragging everything below that level up).

Would you be able to post a DNG on Dropbox (or something similar)? If you can, I'd be happy to take a look at it in darktable and RawTherapee. Both use different raw converters, and both have profiles for the K-1, so they would give useful comparisons.
Thanks a lot, I'll upload one later if I haven't resolved it, my mate thinks it's a colour depth issue somewhere on my end so I'll try and figure that out with him right now.

---------- Post added 23-01-19 at 10:41 PM ----------

QuoteOriginally posted by PDL Quote

You might want to play around with the "linear response" tone curve. It uses the data off of the sensor without preconceived tone curves. The image will look extremely flat and bland but you will be able to push your post processing to what you desire.
.
I'm not trying to get them to look identical, and only tried camera raw because I wondered if things looked fine in there.

Sadly I haven't got the monthly subscription to COne so I'm stuck with 10 for now until my wallet allows.
I did try with the linear curve too, but no luck at all!


Sorry if my reply is a bit short, trying to type and speak on skype is pretty hard!
01-23-2019, 02:44 PM   #7
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What does the histogram look like?
01-23-2019, 05:18 PM - 1 Like   #8
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It's fixed!

It was a dodgy calibration I had on my screen.. the ICC tonal curve looked like this:


Fairly hilarious..


No idea how that even happened.
And I've lived with that since July!...

Edit:
Well, I must say I'm enjoying things much more now!


Last edited by Topsy; 01-23-2019 at 06:06 PM.
01-24-2019, 01:54 AM   #9
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QuoteOriginally posted by Topsy Quote
It was a dodgy calibration I had on my screen.. the ICC tonal curve looked like this:
yikes, I wonder what the hell caused that. It might be a good idea to get in touch with the developer of the calibration software and report this glitch.
02-06-2019, 05:46 PM   #10
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QuoteOriginally posted by Digitalis Quote
yikes, I wonder what the hell caused that. It might be a good idea to get in touch with the developer of the calibration software and report this glitch.
Not sure who I'd get in touch which, I'm using a Color Munki with Dispcal?
Though I doubt it was an user error, but technically ,my cat might have moved it whilst it was doing it's thing, but I'm not sure how realistic that is.
I've yet to try a fresh calibration.


Sorry I'm a bit late answering, had my PC apart for a general overhaul and started enjoying the time without it
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