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09-07-2016, 09:28 AM   #211
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QuoteOriginally posted by MJKoski Quote
I brought my unit to my dealer in Finland who sent it to Sweden to be serviced. But in the end this is good news. Solution is available after all.

For those looking for the issue. Take ISO25600 shot, 30 seconds with lens cap on. It seems that the affected units will have a darkened bar on top of the image. The guy who talked to Focus Nordic folks had also this dark bar in high ISO images.
Just tried this check on mine and the top band is visible in all of my raw converters as well as on the JPEG preview. Just when I was starting to think there might not be an issue with mine, it looks like it will need service after all. Hopefully if it is just an "adjustment" it will be easy for them to do?

09-07-2016, 10:07 AM   #212
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QuoteOriginally posted by Class A Quote
All sensors have a linear response. There is only one dynamic range, i.e., a single dynamic range figure. Terms like "dynamic range in the shadows" or "dynamic range in the highlights" do not make sense. N.B., I realise you did no use these terms, but you associated "highlight pulling capacity" with a camera model and that does not make sense, unless you are talking about the JPEG engine built into the camera.

How much details is preserved in shadows and highlights depends on the design of tone curves that are used during RAW-"development". One can make these curves transition abruptly (maximising their linear portion) or built in soft "shoulders" that make less of the range linear but give a more "film like" look and lead to a more forgiving exposure experience.
I am way out of my depth here, but it has been my understanding that the camera's image processor (Prime IV on the K-1) does apply logic on assigning values from the sensor output. This is at a low level and affects both RAW and JPEG output. RAW is still raw, but it is the raw output from the image processor, not the sensor.


Steve
09-07-2016, 02:14 PM   #213
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I performed the ISO25600 30 sec test. My camera does not have the dark band, however a lot of white spots all over the frame. I repeated the test after doing a pixel test - results in white spots in different locations, no improvement. I then redid the test with ISO NR on. Still white dots and the results look worse than for the first test ran before doing the pixel test and turning on NR!!

I don't understand the finer details of the problem. Is it the consensus that the white dots indicate there is a fault with the camera sensor, etc?
09-07-2016, 03:34 PM   #214
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QuoteOriginally posted by Gimbal Quote
Isn’t it all about at which level the camera displays clipped areas?
You have a point, but I'm sure that's not what MJKoski was talking about.

I think the discussion was about what you can do to an image with lots of highlight content, with "lots of highlight content" not being defined by the camera's feedback (e.g., in terms of blinkies) but by the distribution of tones in the image.

QuoteOriginally posted by MJKoski Quote
Some day we hopefully have a sensor which drops sensitivity when pixel approaches saturation point.
That wouldn't be my ideal. You can get the same today by just preserving highlights and using any soft tone curve in post-processing. It would be better to have "resetting" pixels that just keep on counting photons without ever being saturated.

QuoteOriginally posted by stevebrot Quote
I am way out of my depth here, but it has been my understanding that the camera's image processor (Prime IV on the K-1) does apply logic on assigning values from the sensor output. This is at a low level and affects both RAW and JPEG output. RAW is still raw, but it is the raw output from the image processor, not the sensor.
You are correct in assuming that many cameras massage the data (e.g., apply some noise reduction) before they write it into a RAW file. However, they don't apply tone curves. I once used my K100D's linear RAW output to make absolute light measurements. The results I got were in perfect agreement with what I expected from the light source. That would not have been the case, if the recorded data had not been linear. To do that, I had to use dcraw in a special mode that avoids all white balancing, gamma encoding, mapping into a colour space, etc. There is a lot going on from true RAW numbers to even a very plain and flat looking JPEG file.

09-07-2016, 04:30 PM   #215
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Oh noes...I hope for such dynamic sensitivity to come very soon. That way one can expose for the shadows. This would result in high DR without need for extra tone mapping step. Buffering pixel charge and resetting would result in super high DR but there will be need for extra tonemapping step. 16bit RAW would not be enough anymore.

But..

It has nothing to do with white dots...
09-07-2016, 09:56 PM   #216
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Here is my test, Lens SMC-A 50mm f1.7 @ ISO25600 - 30s - f2.8 (with pinch cap) rezised to 1000*667px

RAW to Jpeg (ACR no procesing of any kind, directly to Jpeg)

IMGP1279.jpg

RAW to Jpeg (ACR plus +5.00 exposure)

IMGP1279_1.jpg

- My camera seems fine
Attached Images
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09-08-2016, 12:17 AM   #217
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QuoteOriginally posted by virusn3t Quote
Here is my test, Lens SMC-A 50mm f1.7 @ ISO25600 - 30s - f2.8 (with pinch cap) rezised to 1000*667px

RAW to Jpeg (ACR no procesing of any kind, directly to Jpeg)

IMGP1279.jpg

RAW to Jpeg (ACR plus +5.00 exposure)

IMGP1279_1.jpg

- My camera seems fine
One important thing to know is if you downsample an image noise and also some of the white dots will dissapear along with detail.
09-08-2016, 02:52 AM   #218
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There is a large light leak somewhere. Some reminiscent of black bar (rather large!) on the top. Could you take the shots with camera under dark cloth sealed from light? At least cover the viewfinder if not already.

09-08-2016, 06:59 AM   #219
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QuoteOriginally posted by Tjompen1968 Quote
One important thing to know is if you downsample an image noise and also some of the white dots will dissapear along with detail.
I downsized the image, but still i didnt see the kind of white specks like some of the images posted in the thread, just regular noise (but i did not clean the image in any way rather to downsize the image)

QuoteOriginally posted by MJKoski Quote
There is a large light leak somewhere. Some reminiscent of black bar (rather large!) on the top. Could you take the shots with camera under dark cloth sealed from light? At least cover the viewfinder if not already.
Yeah, i did not cover the viewfinder... this time i throw a black tshirt when i make picture

IMGP1282.jpg

RAW File

IMGP1282.DNG - Google Drive
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09-08-2016, 07:45 AM   #220
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Did you take the dark bar test with covered viewfinder?
09-08-2016, 07:54 AM   #221
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QuoteOriginally posted by MJKoski Quote
Did you take the dark bar test with covered viewfinder?
The second test i throw a black shirt to cover the camera, the first time, no.

09-08-2016, 08:22 AM   #222
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Did the top bar test - couldn't find it in my shots. No white hot pixels either, 100% crops below, full res jpegs and raw's via link below. Seems my unit it fine. Did at 25600is - 30s (with and without NR), and 25600iso - 120s (with and without NR), all pushed +2EV Color noise reduction in LR - 0, camera profile - Natural, no other corrections.

Update your browser to use Google Drive - Drive Help

Last edited by awscreo; 01-22-2017 at 08:49 PM.
09-08-2016, 09:31 AM   #223
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I also did the test to my K-1 (early unit with a mode selector problem) and I don't see any dark banding on the top of the sensor... I will take some real life pics to see whether there are any disturbing white dots visible.

M mode, 30s, ISO 25600, pushed +3EV in PS (camera with covered VF and under black cloth)
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09-08-2016, 07:06 PM   #224
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Have you tried using another camera such as the K-3 or K-5 to see if it happens with those cameras as well ?
09-08-2016, 07:48 PM   #225
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I decided to do some more dark-frame tests this time with (approximately) 120 second exposure times. I have uploaded raws here. I also tried a new variable that I have not seen mentioned in this thread, which is the highlight and shadow correction. I usually leave the highlight correction on, and the shadow correction on medium. Those are the settings for the files without "NC" in the filename. The files with "NC" have both correction types turned off. To me the noise looks fairly even in all, except for the dark band at the top on the 3200 and 6400 files. Also the files with highlight and shadow correction look somewhat less noisy to me. How do these look to you all? I am fairly sure that I will send mine in for service due to the dark band, but I am curious if the overall noise is worse than ones without the dark band.
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