There are several different photographic formats that can be used for wedding photography. In the past, they had their pros and cons.

Large Format
Large format photography usually refers to using view cameras that have a film negative that is between 4" x 5" to 8" x 10" in size. Cameras that use this size film are called "view cameras". These are very large and cumbersome to use. In exchange, the photographer makes an extremely large negative. In the past, when film technology was not as advanced as it is now, this was the primary way to make stunningly sharp, huge enlargements. With the advent of digital photography and newer film technologies, it is rare to see a large format camera used at a wedding. Today, they are mainly used by film enthusiasts or a professional photographer shooting for a billboard.

Medium Format
Medium format photography generally refers to using camera with a film size of about 2 1/4" square. The size actually varies some, with one edge of the film or sensor being 2 1/4" and the other varying from 1 3/4" up to 2 3/4". There are a few digital cameras in this size, but they are still few and far between. The medium format size is a somewhat cumbersome camera, but it is much more convenient than a large format camera. Many of the better medium format cameras are single lens reflex cameras, which gives the photographer a lot of freedom to move about while shooting. Until digital photography came in to tits own in the last few years, medium format was the preferred medium for most higher end wedding photographers. It is a bit tough to do photojournalism with such a large camera, but some spontaneous photographs can be made at a wedding with one. And the quality has been very good for the last few decades, allowing for beautiful 16" x 20" enlargements. This is typically the largest size that parents have wedding photos made to since, even at this size, the framed photograph will dominate a wall.

35mm format
35mm film cameras are very compact and easy to use in a photojournalistic style. The only problem they have for wedding photography is that the negative is often not quite good enough to make the high quality enlargements that are wanted to hang on the wall. This might not be the case if weddings were in brightly lit areas, but at least part of most weddings are in poorly lit areas. As such, 35mm photography is typically not the preferred photographic medium for a wedding.

Digital format
Digital photography is the preferred medium for most wedding photographers today. It has advanced to the point where beautiful 16" x 20" enlargements can be made from well lit photographs. At the same time, with the flick of a finger, the photographer can change the sensitivity of the camera to shoot photojournalistic style shots in lower light situations where there is a lot of movement. This has brought the best of 35mm and medium format film cameras into one superb instrument: modern digital cameras.