For a regular "normal" lens, the distance from the lens to the subject is greater than the distance from the lens to the film. For any 1:1 Macro work, the distance from the subject to the lens is roughly the same as the distance from the lens to the film. For any magnification greater than 1:1, the distance from the lens to the subject is less than the distance from the lens to the film.

For most Macro photography, due to the magnifications involved, a moving subject is not really a good thing and a slow lens is OK.

The 2 Olympus OM 50mm Macro lenses are also built with small front elements that are deeply recessed and according to Olympus, no hood is required.