Discussion in 'Beyond the Basics' started by mhowel22, Mar 19, 2005.
How do I know if a lens is wide angle of not?
45-50mm is a standard lens, less than that is getting to wide angle - depending on the camera you have as a Canon DSLR will make a normal 28mm into a virtual standard lens because of the crop factor and I think thats true for most dslr's, but I might be wrong
As Tempra stated, a 50mm lens on a 35mm film camera is considered to be similar to what the eye sees. Personally I find that 70mm is nearer the mark.
This means that anything less than 50mm is a wide angle, the lower the number the wider the angle.
Also as Tempra noted the crop factor on a digital spoils this somewhat because a 28mm lens for instance would become equivalent to a 42mm on a digital with a 1.5 crop factor.
This is why the extreme wide angle lenses (such as 10mm) are becoming popular for digitals.
The reason why 70mm seems to be closer to the eye is because of the magnification factor. If you look through the viewfinder in one eye, then open your free eye, you'll find that 70mm seems to match both eyes. However, the reason why they conclude that 50mm is closer to what the eye sees is because it's what most closely approximates our left-to-right natural attention angle of view. Plus, if you were to examine a true model of a 20/20 human eyeball, the way the lenses are arranged in relation to the retina, a 50mm lens is the closest photographic modeled lens.
A "normal" angle lens has the same approximate focal length as the measurement diagonally across the format (film or sensor size). Focal lengths shorter than this are wide angle.
A "normal" lens (50mm) on a 35mm camera has a 46 degree field of view. As the focal range of the lens shortens, the field of view gets wider, thus "wide angle," indicating that the field of view, in degrees, has exceeded the focal length of the lens, in millimeters. (At least, that's the way it was explained to me...) At 35mm, the field of view has expanded to 64 degrees. At 28mm, it is 75 degrees. When you get down to the extreme wide-angle lenses, the field of view is tremendous. A 16mm lens, for example, would have a 115 degree field of view. Of course, this all changes with different types of camera. At 50mm, for example, an APS camera would have a 39 degree field of view, a 6x4.5 would have a 74 degree field of view, and a 6x6 would have an 81 degree field of view. Wide angle is basically a catchall term for any lens with a focal length of 50mm.
(Source: Popular Photography/October 1997)
Basically everything said here is correct, but the easiest way to think of it in terms of simple math, like this:
Using a 35mm film camera...
50mm = standard, like our eyes
25mm = twice as wide
100mm = twice as magnified
you get the picture
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