Why Canon does not add pixel mapping feature?

[lehane19]

This topic was probably talked about a thousand times here, but I wanted to bring it again. I bought Canon R6m2 few months back and while I don’t normally shoot at night this time took couple of shots outside after sunset, handheld with higher ISO and in JPG only since my preference are Canon tones. I noticed some hot/dead pixels in a number of areas, constantly persisting. This of course while viewing at 100% size. And, while zoomed out, it was barely noticeable.

I read somewhere that you could perform Sensor Clean-up procedure within the camera, with body cap mounted on. I did this twice and I wanted to see if this caused some of these issues to go away. To my expectation, it did not help.

I took a number of sample darks to check it out. I share them here.

All examples are 5EV+ to better expose the pixels and to better see the total number of them.


1. R6m2 - before sensor clean.


2 - r6m2 2nd shot before sensor cleanup.


3. c6m2 - raw converted in DPP


4. c6m2 - raw converted in ACR

I also happen to have Fuji X-T4 and I took 2 images. One after one pixel mapping, and 2nd after 2 pixel mapping operations. Also upped by +5EV to see the effect.





So my conclusion is that Canon does not implement any sort of pixel mapping tech, neither in the camera (or by using Sensor clean-up) nor in DPP software. ACR on the other hand does appear to treat these pixels in some way, so the end result is much nicer, though more noise overall, but that’s fine with me. Does that mean I get rid of the camera? No. But in the back of my head I will know that with adobe software I will get better result in this field. I won’t be able to rely on DPP or in-camera function to do anything about this problem, which is a real shame on Canon side not to deal with this in any way.

 

[Kameratrollet]

The sensor cleaning method Clean now is what is used to remove bad pixels at short shutter speed. It is also documented in your manual, page 1030.


Fourth picture shows the same area after Clean now.

For 1 second or longer, use the black frame method LENR, page 273.

At ISO 12800 your camera probably auto-removes bad pixels. Try yourself. Perhaps it removes more pixels than necessary. I haven't checked.

At long shutter speed you will have faster dark current build-up in some pixels, see the link below.

https://www.photonstophotos.net/GeneralTopics/Sensors_&_Raw/Bad_Pixel_Detection.htm

 

[lehane19]

So the suggestions you provided appear to have solved my mystery (thank you). I have to give Canon credit back for having some solution in place.

Initially my intention was to disable all in-camera NR, so I can eliminate colour noise in Adobe (old times habits, since chroma noise was always problematic to me while using SOOC images. ). Since R62 now has much better chroma noise behaviour, I can switch back on the LENR.

Also using Fujifilm for the last few years we know their chroma noise management is a different story altogether, but that's irrelevant here.