Quote:
Originally Posted by MarianHeart
What do you mean by saying that the 20d can be "a little long"?
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It has to do with what's called "the field of view"--or how wide the angle of view in the shot is. The smaller your focal length, the wider the angle gets and the further back you feel, the longer the focal length, the smaller the angle gets and the closer you feel. (See:
demo).
All of the Canon lenses that are designated as "EF" (rather than EF-S) were designed for film. And give the same field of view on a film camera or a full-frame sensor body (e.g., a 5DMkII). But when an EF lens is mounted on a "crop body" digital camera, like a Canon
xxD/
xxxD/
xxxxD body, because the sensor is smaller than a frame of film, will give you a narrower field of view.
The effect is similar to zooming in or cropping, which is why it's sometimes called a crop factor or a crop body. With Canon dSLRs, the crop factor is 1.6x. So a 50mm lens on a crop body has roughly the same field of view that an 80mm lens would on full frame.
If you're sitting across the table from someone, a 50mm lens on a crop body is likely to get you a head shot. If you want to get more of the person into a shot, you'll either have to move the camera back, or use a shorter lens. A lot of people find that 50mm is "too long" for portrait work in social situations. A lot of people don't. This is a matter of personal taste that includes how you like to compose, and what kind of working distances you prefer or have to work in. Smaller spaces usually require wider lenses, because you have to work closer in.
50mm, btw, is also a relatively special focal length for photography, because it's what's called "normal" or "standard." It gives the same magnification that your eye does. If you have a 50mm lens mounted on the camera, and you open both eyes the view through the camera viewfinder and the view with your bare eye will match. Any other focal length, and it won't. That remains the same, irregardless of whether you're using a crop body or a full frame body.