[MJKoski]

It is difficult to say much about dark frames except the dark band which some units have. I had problems with images shot in real conditions and normal post processing tasks where the dots popped up in high amounts. They are easily accentuated in images where there are bright light (no dots visible) and dark areas where shadows are being pushed up. It is this contrast which bugged me the most.

And dark band then, in real world I noticed it when using astro tracker during ~100 second exposures @ ISO3200. I also noted that with the freezer experiment the dark band almost vanishes as the overall noise level in image drops. As if the top part of the sensor is running cooler than the rest of the sensor area?

[loco]

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?

Same here.

I did the test and did not find a dark band at the top of the frame either. I do see some white dots, though. I have noticed when using Astrotracer and higher ISO's and longer exposures that the white dots do show up and it's pretty obvious. So, if I don't have the dark band, but I do have the white dots, is there a fix or is this considered "normal"?

What's weird is, it doesn't do it every time. I have had 100s exposures with no white dots and 60s exposures with white dots. ?

[fromunderthebridge]

Same here.

I did the test and did not find a dark band at the top of the frame either. I do see some white dots, though. I have noticed when using Astrotracer and higher ISO's and longer exposures that the white dots do show up and it's pretty obvious. So, if I don't have the dark band, but I do have the white dots, is there a fix or is this considered "normal"?

What's weird is, it doesn't do it every time. I have had 100s exposures with no white dots and 60s exposures with white dots. ?

I don't think exact consensus exists yet. The only consensus (seems to be) that at least some of the units are experiencing issues with white dots and/or dark band. There is also the comment from the repairs indicating that sensor calibration may be part of the issue. I guess we will be getting more information after some people have had their sensors adjusted (e.g. we will see if performance changes).

A little update.

My camera has arrived at Kamera Service in Sweden. I called him to check on another matter I have with a lens and I asked him about what it is he will be doing with my camera and he described the procedure for me. They will put the camera in a dark environment and then the computer will do a series of tests and adjust the sensor/software accordingly. It takes around 30 minutes for the procedure to finish so I guess it involves a series of long exposures... We will know by thursday or at latest friday if this has helped.

[MJKoski]

Thanks for the information. I have not heard of my unit since last monday but it will come back some day. Loaner unit works as good as "fixed" d810 so no hurry.

[photoptimist]

A little update.

My camera has arrived at Kamera Service in Sweden. I called him to check on another matter I have with a lens and I asked him about what it is he will be doing with my camera and he described the procedure for me. They will put the camera in a dark environment and then the computer will do a series of tests and adjust the sensor/software accordingly. It takes around 30 minutes for the procedure to finish so I guess it involves a series of long exposures... We will know by thursday or at latest friday if this has helped.

Interesting! Thanks for asking about the process.

One can speculate that this process might be doing some combination of three corrective processes:

1. Internal adjustment of various bias voltages on the sensor to reduce electron leakage into susceptible hotpixels

2. Calibration to create default dark frames that are scaled (according to time, ISO, and temperature) and automatically subtracted from every image

3. Calibration to map hot pixels that are skipped or filled with values from adjacent pixels

A careful statistical analysis of pixel-to-pixel correlations (with some foreknowledge of which pixels were hotpixels initially) could help determine how Pentax is "fixing" the raw image to remove these dots.

[Paul2660]

It may be that later cameras have a fix on this already, as it does appear some cameras based on posts here don't show the issue.

However it's quite easy to see on my K1, on any long exposre (at night) in areas that have less illumination or are just dark, here you will see the dots, so the problem is NOT the same as the D810 had as the problem on the D810 existed throughout the entire frame. The fix from Nikon did remove all but about 1% or so.

In the to screens shots below, the image on the left is in LR and left is Capture One. The first crop is showing a area of deep shadows and you can clearly see the dots in through out the image. The 2nd crop is from the same shot, but more towards the middle of frame that has been illuminated by moonlight, and there are basically no dots, or at least no where as many as in the darker areas. These are loaded into C1 and LR with just defaults. C1 just has a process that sees the dots are noise and takes them out, LR for some reason does not, even with local noise reduction applied.

These are from approximate 2 minute exposure, ISO 500, F 4.5 from the 15-30mm at 15mm.

Same problem occurs in the startracer function, possibly a bit worse at least from my work. But there it's possible to shoot a follow LEN frame and this removes the vast majority of the dots, but I still would rather not have to waste the extra time and battery for such an exposure.

Paul C

Attached Images

   

[Paul2660]

My previous crops, when posted really don't show the effect on the LR images, so I tried to show it here.

[stevebrot]

My previous crops, when posted really don't show the effect on the LR images, so I tried to show it here.

Yes, that is pretty nasty. Are you getting any traction with Ricoh/Pentax?


Steve

[MJKoski]

Paul your dots behave like my unit did. Dark areas are affected. But this was the way my d810 worked as well. I could try to find some d810 exposures from my archive where the dots popped up.

[Paul2660]

Yes, that is pretty nasty. Are you getting any traction with Ricoh/Pentax?


Steve

Hi Steve,

The answer from Pentax is to use Long Exposure noise reduction. Yes, this does eliminate the vast majority of the dots, but to me this is very very wasteful and does use up your battery 2x as fast.

Paul

---------- Post added 09-14-16 at 04:43 AM ----------

Paul your dots behave like my unit did. Dark areas are affected. But this was the way my d810 worked as well. I could try to find some d810 exposures from my archive where the dots popped up.

Hi, just saw your posts, in a way I am glad to see you have the dark band, as I have this also in my K1, and it's most distracting with astrotracer shots. Noticed from day one with the astrotracer and told it was a light leak, which as I thought is not the case.

I will try a few 25000 shots to see if the bar is there, assume it will be.

When your camera returns, I would greatly appreciate it if you would let me know if Pentax fixed the problem on yours, as I will need to try and send mine to Pentax USA.

Thanks
Paul C

[fromunderthebridge]

Pretty annoying, if there is some sort of miscalibrated batch on the streets, but only response is unofficial from one of the authorized service shops. Saving grace would be if they are not yet aware of this and would respond when the reports trickle in.

If it's a batch issue, it should be doable to issue a service advisory for the batch of units. Would also save everyone from the guessing game of whether a specific unit is affected or not.

[stevebrot]

The answer from Pentax is to use Long Exposure noise reduction. Yes, this does eliminate the vast majority of the dots, but to me this is very very wasteful and does use up your battery 2x as fast.

Hi, just saw your posts, in a way I am glad to see you have the dark band, as I have this also in my K1, and it's most distracting with astrotracer shots. Noticed from day one with the astrotracer and told it was a light leak, which as

If it were me, I would be back with Ricoh/Pentax and suggest that there is something wrong that LENR does not address. The white dots are not normal noise and the dark band is clear indication of something serious amiss.


Steve

[fromunderthebridge]

Thanks for the information. I have not heard of my unit since last monday but it will come back some day. Loaner unit works as good as "fixed" d810 so no hurry.

Thank you for reporting back with this. So it indeed seems that this is not a systematic (design issue), but rather an issue that can actually be remedied with proper technical voodoo.

[Paul2660]

If it were me, I would be back with Ricoh/Pentax and suggest that there is something wrong that LENR does not address. The white dots are not normal noise and the dark band is clear indication of something serious amiss.


Steve

Hi Steve,

I am reaching out to Ricoh USA, as normal tech support on this issue did not have any ideas. Sadly, as I had expected, on Pentax, the linkage between tech, corporate, and repair is a total mess. It seems like tech support in US is not even a Ricoh location and may be jobbed out, as they keep referring to "Ricoh" when they talk to me, as if they are not "Ricoh". The repair for Pentax DSLR in the US, is not Ricoh but Precision Camera on the east coast, and personally, from talking to them today, not sure they can do this type of a fix. They seem more break fix type repair, or just dropping in parts etc. Not attempting to re-calibrate a sensor.

I am curious, have been curious from the day I first shot the K1, if my camera was a bit out of calibration as it has a very bad tendency to blow out highlights, as if it's weighted too much to shadows. I expose way to the left with mine in bright situations, but still have to remember to check the histogram and image preview.

Shooting the Nikon version of the sensor, D800, 800e and now D810, they were a bit more seemingly center weighted, but I need to shoot both cameras side by side one day.

Paul C