A number of years ago, a friend and colleague was in Denali photographing moose during the rut and dall sheep higher up. If you've never shot in Denali, there is a lottery for vehicle permits for photography in the fall. A lot of photographers don't get a permit and so they ride the bus. The point beyond which you can't drive is the Savage River bridge. From the park entrance to the river you can drive all you want. Beyond the bridge you take the bus if you don't have one of the permits. All day long there are buses going both ways. You get on the bus and ask the driver to let you off when you see something you want to photograph. Then you catch the next bus. So, my friend had been in a discussion about equipment in one of the visitor centers, then he and another photographer got on a bus. The other photographer was very well know and had a lot of covers on outdoor magazines. They're sitting together on the bus and the other guy asks my friend about the depth of field preview button. My friend explained how the DoF preview button worked. The other guy had no idea. In fact he said he just always shot aperture priority with it wide open. He owned top of the line equipment with really good, fast lenses, so when he shot wide open, he got the subject animal in sharp focus and a nice creamy bokah for the background. Just what you'd want for a cover, and it seemed to always work for him. He knew composition and he knew how to photograph animals to get natural, alert looks without disturbing them. He just didn't know some very basic things about photography. You wouldn't want to take any advice he might give about the technology of photography, but his portfolio wouldn't have indicated that.