And how could it NOT be? It's all about optics, which is a doozy of a subject - often lumped in with Relativity in college physics.
One of the newer concepts photographers have had to grapple with since the advent of digital captures is the "crop factor". This is the magnification that is introduced to your pictures when you use a camera with a sensor that is smaller than the size of the 35mm film that your lenses were designed for. You only get the center portion of the field of view in your capture. This is one of those things that is near-impossible to describe to someone, but becomes much easier to "get" when shown visually.
So here's a great diagram that clearly shows why your view is more magnified when you use a smaller sensor, and also why you can't use one of the new lenses designed for these smaller sensors with a full-frame body, such as my 5D II.The inner rectangle is an APS-C sized sensor from a Canon Rebel or 50D. The size of this sensor introduces a 1.6x crop factor, which is to say, at a given focal length your pictures will look "zoomed in" by a factor of 1.6. So a 50mm lens will appear to be an 50 x 1.6 = 80mm lens.
The outer rectangle is the size of an actual frame of 35mm film, and is also the size of the larger "full frame" sensor on the Canon 5D and 1 series bodies. These cameras show no crop factor because they use the same capture area as film.
The outer circle is the diameter of a standard 35mm lens, and you can see that these lenses are overkill for the APS-C sensor size. For this reason newer, smaller diameter EF-S lenses have been designed by Canon, and they can ONLY be used with APS-C sensors. As you can see from the picture, using this smaller lens with a full-frame sensor would result in huge unexposed areas at the edges of the frame. This is why only full-sized lenses can be used on full-frame sensor cameras.
Clear as mud?
1 comment:
Clear mud.
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