Here is what he is talking about the white spots on the moon. You can see them here. They are hot pixels. The 2nd image shows two of them blown up. One is bright and the other dim. When Luminar created a JPEG, it had to demosaic the RAW file to figure out the correct color and levels for each pixel in the image. Without hot pixel removal, there is a very bright pixel and it looks at the neighboring pixels to get their information. Using fancy algorithms, it then calculates the colors to assign for each pixel. The result is what you see in the bottom image, upper left. The brightness of the center hot pixel has overwhelmed the algorithm and caused a ring of pixels around the hot pixel to be incorrectly assigned.

In the case of the dimmer hot pixel at the far right, it is dim enough to not interfere with all the neighboring pixels.

The 3rd image is one that I took and shows a faint star near the moon. Starlight tends to dance around as it passes thru the atmosphere and we can see a more irregular gathering of pixels.

It has also been suggested it was dust on the sensor. Image #4 is an example of dust on the sensor in this field of stars. There were two of them in this image. You can see how it makes it darker and is spread out over a large area. I couple squeezes with an air bulb fixed this problem. Notice the spikes around the bright star. This is caused by the aperture blades. I had used a 85mm f1.4 lens for this image and stopped down a couple clicks and this is then produced. Using a step down ring would solve this problem.

When I looked at the RAW file and opened it with an application that did not fix the hot pixels, I saw red, green and blue colored pixels. Apparently the color information did not survive the demosaicing process and show up in the JPEG as white.

I'm thinking that my camera and my shooting skills both need upgrading . I find I struggle just to keep fast-moving objects in view, never mind spot metering them or locking focus on them . In my experience, landscapes aren't prone to quick, unpredictable movements. I really like that about landscapes....

Thanks for your constructive input. The only difference between what you're saying and what I've been saying is how aperture would be adjusted. With two wheels, one of them controls aperture. With one wheel you have to hold a button down to adjust aperture. Apart from that, everything that you said about the shooting procedure is exactly what I said.

Re your comment that there is never an advantage in using fixed ISO, that very subject is being discussed in another thread HERE.

In that thread the OP cites the situation where the background brightness changes significantly while the brightness of the subject remains roughly constant. For example if a bird comes in to land and the background that it's seen against changes from bright sky to dark water. Auto ISO would have the exposure jumping all over the place, whereas fixed ISO would allow the exposure to be chosen to suit the subject, regardless of what the background was like. It's not an everyday situation, but for wildlifers it's not an unusual situation.

I stepped outside and was surprised to see the moon here in the Pacific Northwest. I grabbed my Panasonic G9 and took a few hand held shots with the Pano 100-400mm lens at 400mm. This is of course the equivalent of a 800mm FOV in a FF camera. I have mixed emotions on the results of my endeavor.

My question pertains to the bright dots that are visible against the dark background. Would dust on the sensor show up this way?
I don't believe there are any stars between the earth and the moon LOL.

Thank you for your insight.

Wayne