I know Navaro has touched on this before a long time ago but I think it's worth bringing up again because I keep seeing it pop up:
A high field of view is good in a normal FPS game. You get to see more around the map, and it helps with motion sickness, giving you an advantage against everyone else. However, this isn't the case with taking GMod screenshots. It causes weird diagonal artifacts and overall hurts the quality of the picture. Even the worst of poses can look a little nicer just by tweaking the FOV. To do this, you can zoom in by holding down right click with the camera tool. Another method is opening up the console, typing "sv_cheats 1" and typing "fov #"
An example of a picture taken with high FOV (90):Jacket, the character sitting in the chair, has issues like longer legs. There's also some extra fluff on the sides of the image, like the door. Unless there's something amazing about the door, it's best to just keep the focus on Jacket and Hoxton.
An example of a picture taken with a lower FOV (30):There we go. There isn't any more diagonal stretching, and the focus of the image is pretty clear. I'm not the most amazing poser in the world, but the improvement is noticeable.
That's the end of my lecture.