EOS R6 RAW Images Consistently Turning Out Noisy/Grainy

[justadude]

Your ISO is set at 25600 on both of these images, which is very high.  You are going to see grain at that level.  Using "Auto ISO" is the reason it is bumping up so high.  I would suggest trying a lower ISO speed instead of using auto.

Using an F/11 lens doesn't help.  Do you have any faster lenses that you can try?  

[Terry_R6mk2]

Lens used was Sigma 150 x 600 mm 

fyi-I have started a new thread for reference purpose. I would really appreciate the responses there.

thanks again.  

[Waddizzle]

You should start a new thread for your issue.  It will place the description of your issue at the top of the thread, where people can find it.  When you do, try to post actual image files that contain EXIF data, preferably uncropped.  You can post RAW files to a file share like DropBox.  

Thanks, ahead of time.

[Terry_R6mk2]

I agree, I have also started a new thread, thanks again.

[johnrmoyer]

I hope some of this might help.

The camera will do noise reduction unless you have turned it off in the camera menus. This is what you see on the camera. I expect that the info screen you are showing does not have the noise reduction applied. The free to download Canon DPP software will do the same noise reduction. Noise reduction will reduce detail in the image, but often can improve an image that will be scaled down for viewing on a screen.

In the camera menus, you may limit the Auto ISO speed that will be used: https://cam.start.canon/en/C012/manual/html/UG-04_Shooting-1_0100.html#Shooting-1_0100_2  

If you enable eye tracking and image stabilization, you may be able to use a slower shutter speed which would result in a lower ISO and less noticeable noise. More light to the sensor would mean a higher probability that the photon count for a particular photo site on the sensor will have an expected value.

If your lens has mode 3 image stabilization, I find that works well for flying birds and enables use of a lower shutter speed. In the camera menu, it might be something like stabilize only for shot.

This example was with EOS R5 instead of EOS R6. EOS R5 has more shot noise than EOS R6 at the same ISO.  Also at F/11, 800mm instead of 600, hand held and following a flying bird. CR3 file was processed with Canon DPP software. The bird was about 150 meters away.

Sandhill Crane (Antigone canadensis) at Salt Plains National Wildlife Refuge in Oklahoma, United States on November 2, 2023

[johnrmoyer]

Further noise reduction possibilities. For a camera with IBIS, it is difficult to cool the sensor chip. As it gets warmer the noise in the image will increase. If planning to edit the raw file later on a computer, the chips in the camera will have less work to do and generate less heat if one turns off things like auto lighting optimizer and peripheral illumination correction in the camera menus. Then one can enable those later when processing the raw file.