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04-04-2020, 05:20 PM - 3 Likes   #1
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K1 Mark II Dynamic Range - Purple and/or Magenta Artefacts

Let's sort out this "dynamic range of K1 Mark II being crappy and giving purple" issue once and for all (or do our best at least). This is inspired by Cameraville's multiple Lightroom-edited reviews of the underexposed Mark II images, where he was very disappointed with its purple blacks


We need to get away from this idea of RAW files being baked because, in my eyes, sometimes it seems they're cooked to near-enough perfectio in the Mark II. I'm shooting at ISO 6400 without an ounce of worry - with my K1 I really wouldn't have done this past ISO 3200, and even that would be a bit of a hesitation.

Cameraville is an awesome channel but he does not do enough to scrutinise the things he is doing. First of all, Lightroom is a pile of poo when it comes to Pentax support. I love everything about it, except camera support. Capture One and Affinity Photo do a much better job (though it took Capture One a good few years to even entertain the Pentax brand )

He also needs to address the simpler but crucial things such as why is it really that the purple artefacts switch from the K! to Mark II as he zooms out? He says in the comments it's due to his PC loading these huge files but this is, I'm afraid, plain wrong. It's actually down to the compressed preview of what you're working on and how this is then processed into a JPEG. If you zoom right in to a test shot of a Mark II after bringing up the exposure by 4 or 5 stops (whatever you underexposed by) then you'll see that upon very close inspection the artefacts disappear in Lightroom, but zoom out a little (say 1:2) and they come back. This is especially apparent once colour noise reduction has been applied above a value of 1. Even with smoothness pushed to 100 it's still there, yet once again disappears on zooming in. When you go to develop a 100% quality large JPEG, the artefacts are there. When you go to develop a TIF, sometimes they're actually gone. Even freakier, when you adjust the tint the artefacts shift very randomly and, at times, either take over the whole photo or completely disappear.


In short, Lightroom needs to sort themselves out! Also, please let's not discuss the dynamic range "test" on DPReview of the K1 Mark II. The K1 photos use a 77mm FA Ltd and the K1 Mark II a DFA 24-70mm. But it's not so much about the lenses as it is about the lighting and that the scene is ever so slightly different. Just look at the champagne bottle reflections and the missing peacock feather on the top-right


Anyways, to prove to you guys how incredible the Mark II truly is I have made a +4EV adjustments profile for Capture One. Just use this as a "style" within the software. If you need help with this just let me know and I'll walk you through it. Honestly I have never seen such incredible image recovery at a 4-stop push. Well, maybe from a D810 but then the noise is equal to that of K1 whereas the Mark II does incredibly with noise.


Another thing I've wanted to mention is this idea of sacrificing fine details for ISO in the Mark II. We have to remember that any attempt to match the noise level in the K1 to that of a comparable K1 Mark II shot would mean a loss in fine details also - in some cases more severely than what Mark II achieves in-camera. Remember that RAW files are just numbers for the software to interpret. Factory-set processing carried out in camera is one of the most accurate ways of messing with those RAW files rather than relying on a bit of software that tries to cater for an entire industry.


So the Capture One "Style" (this is similar to what would be called a "preset" in Lightroom) is there to give you those deep blacks and eliminate any purple and magenta, without sacrificing those hues in any other non-shadow or non-black part of your image. I've not included any white balance changes since that's obviously best left for you to manually manage.

Let me just finalise this by saying that I bet by now you probably think "oh, here we go. Somebody who bought into the Mark II or got a K1 upgraded and is now reaching for sour grapes." Well, nothing could be further from the truth. I actually almost replaced my Mark II with a K1 when I saw those Cameraville videos a few months ago. However I decided to do my own testing and realised there's a lot more than meets the eye - quite literally. Also the AF of the Mark II is so much nicer for BIF and sports. Love it to bits


My attachment is below. Enjoy

I can also make a similar preset for Affinity Photo if anybody is interested.

Attached Files
File Type: zip K1 Mk2 ISO 100 +4EV.costyle.zip (1.5 KB, 99 views)
04-04-2020, 06:09 PM - 2 Likes   #2
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Rule of thumb. Purple artifacts are a flaw in image processing software not handling out of range values properly.
04-04-2020, 07:18 PM   #3
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QuoteOriginally posted by derekkite Quote
Rule of thumb. Purple artifacts are a flaw in image processing software not handling out of range values properly.
Well put.

Also, for those using Lightroom on your computer, iPad or phone, I’ve found that the best profile to start with is ‘Camera Matching - Bright’ rather than the default which is usually ‘Adobe Colour’ or ‘Adobe Standard’. Then lower your tint by 5 - 10 values. I usually just match the positive number by the negative, for example +3 becomes -3. It’s solely based on me having had very good consistent starting points with this method.
04-04-2020, 11:23 PM - 1 Like   #4
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Thank you for clarifying this. I do not have a K1 II (just the K1) but I had similar feelings towards it.

04-05-2020, 12:08 AM - 2 Likes   #5
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I feel the Mark II is one hell of an underestimated camera. IMHO this has to do with dpreview flawed review which was copycatted by every other review site. Dpreview eventually redid their testing but by then it was already too late.

I also agree with the fact that Lightroom is not a very good software for Pentax camera's; a few years ago, I changed to C1 and never looked back. Now that V20 has a dedicated MkII profile, I couldn't be any happier. The files are incredible to work with...
04-05-2020, 02:04 AM   #6
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QuoteOriginally posted by Pentaxke Quote
I feel the Mark II is one hell of an underestimated camera. IMHO this has to do with dpreview flawed review which was copycatted by every other review site. Dpreview eventually redid their testing but by then it was already too late.

I also agree with the fact that Lightroom is not a very good software for Pentax camera's; a few years ago, I changed to C1 and never looked back. Now that V20 has a dedicated MkII profile, I couldn't be any happier. The files are incredible to work with...
Glad you agree. I feel like sometimes saying anything negative is sacrilege in the world of photography. Each must simply find their own optimum tool. Great to hear your experience - the C1 style is there if you need it but to be honest I don’t think many will be under-exposing by 4 stops to then bring it all out. Perhaps only for highlights but then bracketing is probably a better choice? I speak as an amateur so would be interested in people’s methods
04-05-2020, 04:11 AM   #7
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UPDATED

Below is an Affinity Photo Adjustments layer template. You can copy and paste this group of adjustments when pushing your images 5EV above base ISO. I'm sure you can use it in many other scenarios as well but that is what my template is based on anyhow. The adjustment layers are all editable so have fun

Dropbox - Affinity Template for K1 Mark II - Simplify your life

04-05-2020, 07:01 AM   #8
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I shoot with a K1 and process with Affinity Photo, don't have any problem with fringing...
04-05-2020, 07:58 AM - 1 Like   #9
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QuoteOriginally posted by Roadboat24 Quote
I shoot with a K1 and process with Affinity Photo, don't have any problem with fringing...
Hey Roadboat24, I meant it as a way of addressing the purple artefacts on a Mark II once you've pushed the exposure by about 4 or 5 stops

Unless that's what you meant of course.
04-05-2020, 08:17 AM   #10
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I quite like the automatic noise reduction on the k1mii, almost all the time I just don't need to add any additional in pp. It's simpler, and I am very happy with the level of detail, can't say I've noticed artifacts.
I've been processing with darktable, as with the k3ii before. Never had issues with false color in use but I rarely push 3 stops just because it's a lot already
04-05-2020, 09:22 AM   #11
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Same (current) version of lightroom handles K-1 mk1 and mk2 differently. MK2 gives me this with underexposed and pushed ISO100 files:



No such issues with MK1. If anything, pushed MK1 RAW-files produce more white dots but not magenta tinted shadows which simply do not go away simple tint-adjustment. Either Adobe messed something up or MK2 imaging chain has serious flaw here. I took that example in July 2018 and Rawtherapee release from that timeline also ended up with the same magenta tint.
04-05-2020, 09:25 AM   #12
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Thank you for your article. But, a question. How are you importing images into Lightroom, as DMG files or PEF format? I don't yet have a K1 but am interested in these articles?
04-05-2020, 09:47 AM   #13
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QuoteOriginally posted by MJKoski Quote
No such issues with MK1. If anything, pushed MK1 RAW-files produce more white dots but not magenta tinted shadows which simply do not go away simple tint-adjustment.
I have more white dot on my K1 II, so I think it's not related to the camera being a Mk1 or Mk2 but rather related to the sensor itself.
You can easily correct shadow tint adjusting the red tone curve for low levels. I did that to correct for WB in shadow and it worked great.
Not everyone needs to push 5 stops of shadows, I never push more than 3 stop because I use 2, 3 and 4 stops soft ND grad filters which helps balance noise across the frame, do so it much better than exposing for the high light and pushing shadows like crazy. There is also the method of taking two or three bracketed shots and stacking them with luminosity masks it's also much better than pushing shadows 4 or 5 stops.
04-05-2020, 10:38 AM   #14
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If I just correct this shadow tint the colors get messed up all over the image and at all luminosity levels. This is what happens with Adobe converter right now. I suspect there are better copies of MK2 in circulation just like it was with uncalibrated MK1 units producing masses of white dots. We do not know if MK2 models are just factory updated MK1 cameras to get rid of the old supply. And if so, it would explain the differences why some users never see this magenta cast and some do. The culprit would be calibrated vs. uncalibrated MK1 bodies getting the update to MK2.

My first MK1 unit was calibrated twice. I noticed different magenta/purple noise profile with the uncalibrated camera body compared to the same camera body after the calibration was done.
04-05-2020, 10:48 AM   #15
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QuoteOriginally posted by MJKoski Quote
If I just correct this shadow tint the colors get messed up all over the image and at all luminosity levels.
No , because you adjust lower the tone curve of the red channel only for the range of shadow where you have the unwanted color cast.

QuoteOriginally posted by MJKoski Quote
We do not know if MK2 models are just factory updated MK1 cameras to get rid of the old supply. And if so, it would explain the differences why some users never see this magenta cast and some do.
The sensor is the same. Magenta cast comes from either wrong icc profile use by the raw converter that assumes that K1 Mk2 icc profile is the same as K1 Mk1, or K1 Mk2 raw processing firmware that differs from K1 Mk1.
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