A studio is a place that serves your needs, whether it is a converted garage, a light-filled loft or an extra room in the house that can be emptied of furniture to leave room for the photographic work.
Studio size obviously depends on the subjects to be photographed. Still- life subjects require minimum space. For people or large objects, more room is necessary.
The general rule for people pictures is that the space has to be large enough for the photographer to get a full-length image of a standing subject through an 85mm lens. That requires the camera to be about 20 feet from the subject. If the subject is at least three feet from the background and the photographer has some space to move, the room has to be at least 25 feet long.
If there is no room that big, one solution is to use a short-focal-length lens, such as a 50mm. Another is to shoot only head-and-shoulders close-ups.
A studio should be wide enough to keep lighting equipment and reflectors out of camera range, and the ceiling should be at least 8 or 9 feet high.
Most homes have a room that can serve as a photo studio, although there may be a conflict over the use of that room, or a problem with storage of the furniture or the camera equipment needed there.
Rooms with a lot of daylight give a photographer a natural advantage. The light can be diffused and, with reflectors, redirected. A room with north- facing windows and skylights for top light can be used for a daylight studio. A room that is drenched in light needs blinds and diffusers to soften and distribute the light.
The background can be a simple one. Many of the sumptuous backgrounds found in slick product ads are painted backdrops or photo background paper, which is 9 feet wide. Photographers who want a range of backdrops buy several rolls and support the rolls window-shade-fashion, pulling down the color needed. In most cases, the background should be lighted separately from the subject.
Some highly paid studio photographers in New York work in spaces not much larger than an average room (8 by 9 feet). The secret lies in the intelligent use of the space.