Photographing in an archive:
The University of Illinois at Urbana-Champaign offers a great LibGuide on Using Digital Tools for Archival Research. It covers not just cameras and how to take photography in archives but also tips on organizing images and information. A highly recommended resource.
Photographing in a museum:
First things first: check the museum photography policy. It’s usually available on the museum website. Usually photography is permitted in the permanent collections (without a flash) but not in the temporary exhibits. If you are a graduate student with specific questions regarding photography please contact the departmental photographer, John.