I always shoot with spot metering because the subject is the most important for me since I mainly shoot to paint from and will be putting in a different background anyway. I was panning with this dog as she was running and jumping, the images are cropped.

This shepherd is just one example, I couldn't find my images of Hallie I tested this on, but it was a bright day, Hallie is of course dark and was against a neutral background (lawn). So it was metering off her dark body since I use spot metering. So if anything the background should have been a little too bright as it was metering off her black. But it wasn't, it was way too dark.

I took several shots, each time opening it up one more stop. The wider the aperture got, the darker the image got. I still don't understand that, I would think it would have gotten brighter. I was told it was because my shutter speed got so high in the bright conditions that it caused the image to go too dark. But that doesn't make sense to me. So it isn't from what it is metering on as I've tested it on a static scene. By the time I shot Hallie at 2.8, the image was almost black and this was on a bright sunny day, but the ss at that point was up to 1/8000.

I'm not quite following your idea on using aperture priority going a bit dark, aperture priority would first lower the shutter speed so it shouldn't go too dark (unless it was very low light and then it would be dark and blurry both). The reason I have been using shutter priority is because I would rather stop action if there isn't enough light for both that and good exposure, that way if it's too dark I can lighten it in PS and still have frozen the action. If I used aperture priority, it would be exposed correctly out of camera but there would also be some blur which I can't correct.

I agree about being able to be more creative with aperture priority, that is why I am frustrated with it. I have posted this problem on several boards and not gotten a plausible answer so I have to resort to using shutter priority. I do use aperture priority on things that aren't moving. I can't use manual with situations like the german shepherd because like I mentioned before, things are happening too fast and I would not be able to fiddle with the manual, i.e., if the 8 frames per second images of this jump go from correctly exposed to dark, 8 times in one second so I could not have changed settings during that one second that fast.

I have had no problems with the exposures using shutter priority but it does not let me blur out the backgrounds for the action shots and sometimes I don't have time to change to aperture priority when the horse stops because I am shooting like crazy and the horse stops and starts again and there is no time to switch. It's not a problem if it's a posed, still shot then aperture priority works fine.

I am probably not making any sense but I'd like to figure this out although I did get a ton of suggestions on several forums and it was never figured out. I really don't think there is anything "wrong" with my camera it may be something I just am not getting yet but if so I dont have a clue what that is.