Civil War photographers had a tough time of it. All of their equipment, chemicals, camera, and a darkroom had to be brought to the battlefield usually in a wagon. The "film" was known as "wet plate", i.e. a piece of plate glass onto which light sensitive chemicals were 'painted'. The act of taking a photo was a very detailed process. First the photographer positioned and focused the camera. Then he mixed the chemicals. The chemicals were then applied to a piece of plate glass to sensitize it to light. The plate was then brought into a dark room where it was immersed in silver nitrate.
The plate was then placed into a light-tight container and inserted into the camera. The photographer then removed the cap on the camera for 5 to 20 seconds to expose the wet piece of glass to light which would imprint the image onto the plate. The cap was replaced and the plate glass, still in its light-tight container, was taken to the darkroom where the image was developed.
Obviously there were NOT going to be any action shots. Photos had to be staged beforehand and no one could move during the process which is why photographs of the era look so staged and the people in them so stiff and rigid.
Photographers of the era were also not above having scenes staged for dramatic effect. Bodies moved and arranged. guns placed just so. All for effect