In most cases, manufacturers label their cameras and lenses with their actual focal lengths, but in some cases they have chosen to instead multiply by the crop factor (focal length multiplier) and label the 35 mm equivalent focal length. Reviewers also sometimes use the 35 mm-equivalent focal length as a way to characterize the field of view of a range of cameras in common terms. For example, the Canon Powershot SD600 lens is labeled with its actual focal length range of 5.8–17.4 mm. But it is sometimes described in reviews as a 35–105 mm lens, since it has a crop factor of about 6 ("1/2.5-inch" format). Magnification factor The crop factor is sometimes referred to as "magnification factor", "focal length factor" or "focal length multiplier". This usage reflects the observation that lenses of a given focal length seem to produce greater magnification on crop-factor cameras than they do on full-frame cameras. This is an advantage in, for example, bird photography, where photographers often strive to get the maximum "reach". A camera with a smaller sensor can be preferable to using a teleconverter, because the latter affects the f-number of the lens, and can therefore degrade the performance of the autofocus. A given lens casts the same image no matter what camera it is attached to. The extra "magnification" occurs when the image is enlarged more to produce output (print or screen) that matches a standard output size. That is, the magnification, as usually defined from subject to focal plane, is unchanged, but the system magnification from subject to final output is increased. Secondary effects When a lens designed for 35 mm format is used on a smaller-format DSLR, besides the obvious reduction in field of view, there may be secondary effects on depth of field, perspective, camera-motion blur, and other photographic parameters. The depth of field may change, depending on what conditions are compared. Shooting from the same position, with the same lens and same f-number as a non-cropped (full-frame) 35 mm camera, but enlarging the image to a given reference size, will yield a reduced depth of field. On the other hand, using a different lens with the same field of view as the non-cropped camera (matching the 35 mm-equivalent focal length), at same f-number, the smaller camera's depth of field is greater. Perspective is a property that depends only on viewpoint (camera position). But if moving a lens