DSLR Cameras With APS-C Sensor
Most digital SLR cameras on the market are based on an APS-C image sensor, the size of which measures approximately the same as a Classic-sized frame of Advanced Photographic System film (25.1×16.7mm). If you don’t remember APS cameras, they made a small splash in the compact film camera market – just before becoming obsolete when the world went digital.
A big bonus of an APS-C-sized sensor is that you get a ‘crop factor’. This boosts the effective telephoto length of a lens on a Canon DSLR by a factor of 1.6x, so shooting with a 70-300mm telephoto zoom lens gives you an effective maximum reach of a mighty 480mm, more like that of a super-telephoto lens.
However, in a classic case of swings and roundabouts, what you gain at the telephoto end, you lose when it comes to wide-angle shooting. In this case, a conventional ultra-wide lens with a focal length of lets say with 16mm, which will be equates to a merely moderate 26mm.
Naturally, not all DSLRs use APS-C-format sensors and the stunning Canon 5D Mark II is an excellent example of one that uses a full-frame sensor, the same size as a frame of regular 35mm film (36x24mm). With cameras like this, what you see is what you get, so if you put a 16mm ultra-wide lens on the body, a focal length of 16mm is what you are going to have.
To give true ultra-wide fields of view on APS-C cameras, lenses need to be specially designed and manufactured for the purpose. The difficulty and expense in doing this meant that. not so long ago, you were limited to a very small choice of two or three ultra-wide lenses for APS-C cameras like the 350D and 30D. With the massive growth in popularity of APS-C cameras over the last few years, however, there’s now much more choice on offer, with lenses like the new Sigma 8-16mm giving very wide effective zoom ranges of 13-26mm.
One important buying consideration is that, while you can use a full-frame lens on an APS-C camera that has a smaller sensor like the 550D. there’s no such compatibility the other way around, so you can’t fit a lens designed for an APS-C camera on a full-frame body like the 5D Mark II. You need to choose wisely and the clue is in the letters.
Cameras That Featured With APS-C Sensors
Canon EF-S, Sigma DC, Tamron Di II and Tokina DX lenses are all engineered for cameras with APS-C sensors, so are only compatible with cameras like the 1000D, 550D, 60D and 7D. Conversely, Canon EF, Sigma DG. Tamron Di and Tokina D-series lenses are primarily designed for full-frame use, but can also be fitted to APS-C camera bodies.
There’s actually a plus point in using lull-frame lenses on APS-C cameras, in that the sensor can only ‘see’ the central area of the overall image circle produced by the lens, where image quality is at its highest. However, while this can be a bonus in standard focal length and telephoto lenses. it’s largely irrelevant for ultra-wide lenses, as you simply won’t achieve the wider field of view that you’re after.
Ultimately, the Ultra-wide arena is the only one where the lens you choose is wholly governed by the size of your camera’s image sensor.