The University of California Riverside offers a certificate program in crime scene investigation. In the outline for the Crime Scene Photography Course [info] instructor Steven Staggs includes the following information on what makes a photo admissible as evidence:

a. Object pictured must be material or relevant to the point in issue

b. The photograph must not appeal to the emotions or tend to prejudice the court or jury

c. The photograph must be free from distortion and not misrepresent the scene or the object it

Photographs must be correctly exposed, have maximum depth of field, be free from distortion and be in sharp focus. You do not need to be an expert in photography to take crime scene photographs or testify about them. 

This, of course, goes against everything that the great crime scene photographer known as Weegee stood for [info]. And the course outline does nothing to suggest that a custom tripod might be the ultimate tool. Photos from the New York City Municipal Archives, above, offer two distinctive views of crime scene evidence in Manhattan's Little Italy, shot some time between 1916 and 1920. Note the legs of a tripod visible in the overhead view.

The New York City Municipal Archives holds over 30,000 crime scene photos, said to be the largest collection of criminal justice evidence in the English-speaking world, here