Unusable images with Canon R5 and 100-500mm RF lens

Photo67 wrote:

Hi! I made a trip to Alaska this summer and I'm sooo disappointed that many of my images are not usable. I'm a full time photographer specializing in nature and wildlife. I've got decades of experience, starting with slide film. However, my results from this past trip have me stumped. So many of my brown bear images have an odd result.

The cub on the left appears sharp (although wet, because of course it was raining). The cub on the right, especially the face, shows the issue I'm having. Some of the images lose their sharpness and look more painterly. I can't print this large and have it look good. It's not blur from movement, it's not exposure. I've never had results like this before, so I'm assuming its either the R5 or the lens. I did originally have the IS settings wrong when I first started shooting, and sadly many of my distant images are not usable. After a bit of research, I found I had the tab on the lens on the wrong IS setting. However, I still can't figure out this issue. Especially, when most parts of the image are sharp.

Has anyone run into this? Or does anyone have any thoughts? I'd be so incredibly grateful if I could find a fix, but I fear that's too much to ask.

PS I am new to zooms. My fav lens has always been my 500 f4.0. Also, these are hand held, but at higher ISO, in case that matters.

Thanks in advance for any feedback.

From what we can see, the following is true:
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* The lens stated is not reflected in the EXIF data.
* I don't feel that the IS was the problem here.
* The high resolution R5 sensor should be capable of resolving detail.
* The image 'appears' to have been tightly cropped.
* The image shows an aperture of f/9.
* The image appears to have been subjected to strong Noise Reduction.
* The image appears to be overexposed.
* The image was shot with an unusually high ISO 6400 (which would be fine if a Circular Polarizer was used).  Without a CPL, the high ISO and exposure setting will likely produce some less than ideal looking grass and highlights in this scene.
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My only thought is that the exposure was cranked down or up, resulting in the photographer being forced to reduce the aperture and raise the ISO to keep the shutter speed up at a "safe" range.  Now I've used high ISO settings of 6400 but usually only in shadow or overcast weather when the light was less than ideal and I was using a filter to avoid overexposing highlights.  The foreground details show blown-out highlights and I simply feel that the image looks over brightened.  The high ISO is a clue but the narrower aperture suggests another influencing factor might be at play.
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I'd have used a CPL or ND filter, shot at f/7 (if indeed shooting with the RF 100-500L) or less (depending on the light).  I'd have used Auto ISO (or at least a much lower ISO setting).  The grass and foliage often reflect a lot of light from certain angles at certain times of the day, so I'd be inclined to definitely be using a CPL filter to reduce that effect.  The bears do look like noise-reduction outside of the camera was used, during post processing.  The file type matters little because this camera produces beautiful JPEGs that can match a well edited RAW file.  So assuming the image hasn't been overcorrected in editing, there's not much more than can be suggested.
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Here's what I think happened (regardless of the lens used):
Canon metering is pretty decent.  The lenses used (whether EF 100-400L II or RF 100-500) produce excellent results and a nearly identical image to one another.  The R5 and R6 (which I use) have the same available settings and produce the same results when viewing the images at the same size.  But an ergonomics issue with some DSLRs (which probably affects the R-system cameras in the same way) means that when shooting and turning the dials on the rear (or activating the M-Fn selector switch simultaneously), it is/was possible to accidentally dial the Manual Exposure Compensation and the Auto Exposure Bracketing (AEB) up or down without realizing it, resulting in an overbright or overdarkened scene.  I've done this myself on DSLRs.  This forces the user to select unfavorable ISO and Aperture settings which can then indeed produce the results shown whilst trying to compensate for what might seem to be whatever is needed to get the scene to look normal on the LCD.  You tend to only notice this has happened when reviewing images later on the viewfinder display or when glancing down at the screen.  When this happens, the same issue should appear with all the photographs taken up until the users resets the settings or notices the problem.