The crop factor, digital SLR or multiplication factor of the lens, has the effect of crop the edges of an image, broadening the central area. The end result is similar to using a longer lens, or a tele converter.
The effect of clipping occurs because the sensor on most digital SLR cameras is smaller than a 35 mm slide or negative.A "frame" of 35 mm film is 36 x 24 mm in size, while the sensor Digital Canon Digital Rebels (300 to 500 d) and the EOS ** range D (50 D 20 d and 7 d) is only 22.5 x 15 mm in size. a sensor smallest to receive the image means that some of the image will be cropped.
Think of it this way: you're watching a presentation on a screen that is just big enough to accommodate the full-size image, and then someone replaces it with a screen that is smaller. Now some of the projected image (top, bottom and sides) "overflow" the small screen, so that what you see now is a version of the image cropped.
You get a similar result when using a digital SLR camera with a sensor that is less than a piece of 35 mm film--the image expressed by lens "overflow" sensor. Any spare space around your subject is cropped away, so the subject now fills most of the frame--but if there is no spare space, part of the subject itself gets cut.
This cutout or magnification is an advantage when using a telephoto lens, as the result is similar to using a longer lens or 1,6 x Converter.
However, for anyone wide-angle shooting, the opposite is true. Now that terrible wide angle so appreciated for creating dramatic landscapes or indoors close is made useless seeds.A real wide-angle as a Canon EF 24 mm gets "stretched" 1.6 x, giving him a focal length equivalent of 38.4 mm on your Rebel XSi or 50 D.
Fortunately, Canon and other digital SLR manufacturers realized that they had to produce lenses for overcoming the crop factor for photographers using wide angle lenses.
The result is a range of lenses for digital SLR cameras with smaller sensors of 35 mm film (often called sensors APS-C format). While the crop factor still applies when using these lenses, the lenses themselves are "shorter", both physically and in focal length, than the lens equivalent to a 35 mm camera.
So the kit lens for Canon Rebel is THE EF-S 18-55 mm.This should be classified as "ultra wide" (wide end) to a 35 mm camera, but equals one more mundane 28.8-88 mm standard zoom--or--when used with a Rebel XSi or 50 D.
While the rebels and EOS Canon ** D digital SLR are classified as entry-level or "prosumer" cameras, they are also used by professionals, in particular, wedding photographers, not previously be adequately met by wide angle lenses available, particularly in terms of image quality and the focal length.
To work around this, Canon has introduced two lenses that are standouts within its range of lens EF-S for use on rebel and EOS ** D cameras:
* Canon EF-S 17-55 mm f/2.8 IS USM
* Canon EF-S 10-22 mm f/3.5-5.6 USM
THE EF-S 17-55 mm is notable for its constant aperture of f/2.8 throughout the zoom range which, together with image stabilization, makes it particularly effective for shooting in low light without flash. It is highly ranked by photographers of wedding and portrait and also as a walkaround lens.
Users like the lens for its sharp pictures at all focal lengths, autofocus fast, versatile and excellence in low light conditions are Their main dislikes. the price (is the most expensive EF-S lens), insufficient Weather sealing, plus the size and weight.
It however receives a score of 91% of users and is a highly recommended as a top quality lens for APS-C format cameras.
THE EF-S 10-22 mm is remarkable, as is the only true ultra wide angle for Canon Rebel EOS ** bodies d. Adapt this objective on your Canon 40 d and is equivalent to a 16-35 mm on a 35 mm or full-frame, offering creative photographers opportunities not otherwise possible with APS-C format cameras.
Users as an objective for its excellent sharpness, colors, autofocus fast and minimal distortion. They don't like the price, construction of plastic and lack of a lens hood supplied.
But the image quality is favourably compared to that of a Canon l series, and users give a rating of 90%, recommending it as essential for anyone who wants wide-angle real capacity on a rebel or EOS ** D body.
Users of Canon Rebel or EOS ** reflex D you can no longer blame their kit lens for less than stellar image quaility it--alternatives are available (although at a price).
Macaskill Scotch is a former photojournalist turned would-be wildlife photographer who now works from home to develop his site to photograph wildlife. Although not a fanatic of brand, he uses cameras Canon Digital Rebel and wide-angle photography recommends Canon EF-S 17-55 mm and Canon EF-S 10-22 mm.
