EOS R5 Terrible noise problem

[lostinCR]

I've had the R5 for 2.5 years and it has been through a lot of travel with me to areas both dry/dusty and humid/dark.  It has always given me great photos and I have been very happy with it.  I had it professionally cleaned in the USA after trips to Africa and South America.  On my most recent trip to Colombia, I have had terrible problems with noise.  Let me be clear, I am not a professional.  I think I know how to use the camera correctly but am 100% willing to be told I am doing something wrong.

I've included two random photos from a trip to Colombia that show my problem.  The first is a night photo where the moon is totally blown out but the shadows are complete noise.  The second is a random orchid at ISO 800 that is almost completely unusable due to noise. I have hundreds more I can include.

I have changed setting on the camera multiple times to use every combination of options I can think of but the noise levels never change.  Is there something obvious that I am missing or do I just need to send the camera back to Canon for a diagnostic?

[johnrmoyer]

I also use an EOS R5. I hope some of this might be helpful.

I found that after a few years, running the "Clean Sensor Now" option in the camera helped the noise. I have hesitated to spend money sending the camera to Canon for cleaning and bought another memory card and battery instead. https://cam.start.canon/en/C003/manual/html/UG-07_Set-up_0280.html#Set-up_0280_1 

I usually use Canon DPP software to develop raw files. When there is noise, I set the unsharp mask fineness to larger than the noise, usually 3.0 or 4.0, instead of my usual 2.0. Sometimes I will reduce fineness below 2.0 if there is no noise and fine detail that could use more contrast. https://en.wikipedia.org/wiki/Unsharp_masking  https://www.cambridgeincolour.com/tutorials/unsharp-mask.htm  The unsharp mask numbers will be different in other software, but I find it helpful to think of "fineness" as related to a radius or diameter in pixels. If noise is one or two pixels, then a fineness setting of 3.0 will be large enough to not sharpen noise.

As mentioned by Peter, it is possible to sharpen an image without sharpening the noise. Here is a gimp tutorial on "smart sharpening": https://www.gimp.org/tutorials/Smart_Sharpening/ 

Some camera settings that will sometimes increase noise or make noise more visible under some lighting conditions when any of the exposure settings are automatic include:

• auto lighting optimizer
• peripheral illumination
• distortion correction
• clarity

In DPP, digital lens optimizer defaults to a level which varies with ISO. More DLO is possible when there is less noise. If using other software that attempts to remove small aperture diffraction blur during "capture sharpening" or using a Richardson/Lucy deconvolution, it would be good to do less as the ISO increases. In camera, the DLO amount is chosen differently than in DPP but that does not matter if using raw files.

A higher "clarity" setting in DPP will sometimes make noise more visible.