The crop factor digital SLR camera or lens multiplier factor has the effect of trimming the edges of an image and the extension of the downtown area. The end result is similar to a longer lens or a tele-converter.
The cutting effect occurs because the sensor on most digital SLR cameras is smaller than a 35mm slide or negative. A "frame" of 35 mm film is 36 x 24mm in size, while the digital sensor from Canon Digital Rebel (300D to 500D) and EOS D-series ** (20Dfor 50D and 7D) is only 22.5 x 15mm in size. A smaller sensor means to maintain the image that some are derived from photos.
Think of it this way: you can only see a slide show on a screen that replaces just big enough to hold the image in full size, then someone with a screen that is smaller. Now some of the projected image (top, bottom and sides), "overflow" of the small screen, so what you see now is a cropped version of the image.
You get a similar resultWhen you use a digital SLR camera with a sensor, the film is smaller than a piece of 35mm – the occupation by the image sensor lens "overflow" l '. Every available space around the subject away circumcised, so the problem now is to fill most of the frame – but if there is lack of space, part of the thing itself is circumcised.
This cropping or magnification is an advantage when using a telephoto lens, the result is similar to using a longer lens or 1.6 xConverter.
But for those wide-angle, the opposite is the case. Now, impressive wide angle, so dramatic landscapes and interiors shooting will be appreciated by half useless. A real wide-angle lens like a Canon EF 24 mm is "turned" by 1.6 times, giving a focal length equivalent of 38.4 mm on your Rebel XTi or 50D.
, And other manufacturers of digital cameras Canon made fortune producing lenses exceedThe crop factor for photographers with wide-angle lenses.
The result is a selection of film lenses designed specifically for digital SLR cameras with sensors smaller than 35mm (often referred to as APS-C). While the crop factor is whether these lenses, the lenses were "shorter", both physically and in focal length compared to the same target for a 35mm camera.
So the kit lens for Canon rebelthe EF-S 18-55mm. This would be classified as "Ultra Wide" (at the end of width) for a 35 mm camera, but a more mundane, 28.8-88mm – or standard zoom – when used with a Rebel XTi or 50D.
While Canon EOS Rebel SLR digital cameras and D ** are classified as entry-level or "prosumers" are also used by professionals, including wedding photographers, who up to now not sufficiently satisfied by the wide-angle lenses,particularly with regard to image quality and focal length.
To overcome this problem, Canon has introduced two lenses that shine are within its range of EF-S for use on the EOS Rebel and D **:
* Canon EF-S 17-55mm f/2.8 IS USM
* Canon EF-S 10-22mm f/3.5-5.6 USM
The EF-S 17-55mm is known for its constant f/2.8 aperture throughout the zoom range with image stabilization, together makeespecially effective for shooting in low light conditions without flash. It 's very sought-after wedding photographers, as well as a portrait lens walkaround.
Users, such as the lens for its sharp images at all focal lengths, autofocus speed, flexibility and quality in low light. Their main task is not like the price (it's the most expensive EF-S), time-poor estate, and the size and weight.
However, receiving a score of 91% of users and ishighly recommended, as the camera a lens of superior quality for the APS-C.
The EF-S 10-22mm is noteworthy because it provides the only true ultra-wide-angle lens for Canon EOS Rebel and D. ** Fit on the Canon 40D and this lens is equivalent to a 16-35mm on a 35mm full-frame or body and gives photographers creative ways not possible with APS-C format cameras.
User as the target for the sharpness, good colors, fastAutofocus and minimal distortion. They do not like the price, plastic construction, and the absence of a hood proposed.
But the image quality is a lens than a Canon L series, and users give a rating of 90% recommend it as essential for all those wide-angle capability on a real body or ** EOS Rebel D.
Users of Canon EOS Rebel D ** or SLR lenses can no longer blame their kit for less than stellar image quaility -The alternatives are available (albeit at a price.)
