I was surprised to learn that even officers in the pre-WWII Signal Corps were, or could be, trained in photography; among my father's effects was an ID badge with his picture, as a young lieutenant, authorizing him to take pictures on-post at Fort Monmouth, New Jersey (this would have been in 1939). I knew that the earliest picture of me as an infant was taken with a Speed Graphic belonging to the Army, but until I found the ID badge I had never wondered why he had access to large-format equipment and a darkroom in 1949!
I do remember him telling me that his standing instructions for the men under him were a) always use a flash bulb, regardless of the existing light; b) set the lens shutter at f/8, and 1/100th; and c) DON'T TOUCH THE FOCAL PLANE SHUTTER!. The first two rules pretty much guaranteed a printable negative (although it might be either thin or dense) and the last rule was to insure that the first two rules mattered, because the average GI seemed to be congenitally incapable of remembering to rewind the focal plane shutter. I assume that ground-glass focusing and composition was not a standard procedure.....