Exploring with the wide end of the focal spectrum opens up a world of creative compositional possibilities
By Mike Stensvold
My high-school chemistry teacher's favorite phrase was "Everything is relative," and so it is with wide-angle lenses. A lens of a given focal ength can be wide-angle, normal or even telephoto. It depends on the format of the camera on which you’re using it. The larger the film frame (or image sensor), the wider a given focal length's angle of view.
For example, a 50mm lens is considered normal for a 35mm SLR. But on a consumer digital camera with a fingernail-sized image sensor, a 50mm lens becomes a supertelephoto, equivalent to maybe 300mm on a 35mm camera. Put a 50mm lens on a 4x5 view camera, and it's an extreme wide-angle, equivalent to maybe 15mm on a 35mm camera (assuming it casts a large enough image circle to cover the 4x5-inch image area).
Any lens with a focal length shorter than the diagonal measurement of the image frame is considered wide-angle—for 35mm cameras, lenses shorter than 43mm are wide-angles, and for APS-C format D-SLRs, lenses shorter than 28mm are wide-angles. There are currently more than 60 lenses available with focal lengths of 28mm or shorter, giving even D-SLR users true wide-angle capability.