@ebiggs1 wrote:
As EF lenses are designed for FF cameras you are going to suffer or benefit from the appearent 1.6x conversion factor. All lenses whether EF-S or EF have this. IE a 50mm lens will appear like a 80mm lens on a FF body. However the AOV always remains the same no matter which body it is used on.
Huh? Sorry, but that's completely backwards.
It is correct, that all EF and all EF-S lenses can be used on your T5i.
If you have never owned and used a 35mm film camera, never used a so-called "full frame" digitial SLR, or don't use the T5i alongside a "full frame" DSLR now... You can simply forget about the 1.6x conversion factors. It isn't necessary to do any math and calculations unless you have preconceived notions about how focal lengths perform or are switching back and forth between the different sensor formats.
Focal lengths don't change, no matter what format they're used upon. A 50mm lens remains a 50mm lens, no matter what, for example.
How that 50mm behaves on different sensor formats does change. The Angle of View of any given focal length is precisedly what does change, depending upon what format it's used upon. What ebiggs means by "suffer or benefit" is that while telephoto lenses are made more powerful using them on crop sensor cameras like T5i, full frame wide angles are no longer very wide when used on a cropper. For that reason, there are a number of ultrawides made especially for crop sensor cameras.
But, all you really need to know is, on your T5i:
- So-called "fisheye" lenses give extremely wide angle of view... ranging from about 150 to 180 degrees, approx. You'll find fisheye focal lengths ranging from 4.5mm to 15mm. There is a great deal of distortion of straight lines with fisheye lenses, so they are fairly specialized.
- Ultrawide non-fisheye lenses for your camera range from 8mm to about 15mm.
- Wide angle to slightly wide lenses are 16mm to 24mm.
- Standard or "normal" lenses are 28mm, 30mm or 35mm.
- Short telephoto are 40mm to about 85mm.
- Moderate telephoto are 90mm to about 180mm
- Super telephoto are 200mm and longer.
Prime lenses have only one focal length, such as 50mm. Zooms have a range of focal lengths and might cover several of the categories above, such as an 18-135mm that goes from moderately wide to moderate telephoto.
Compared to full frame compatible EF lenses, Canon EF-S lenses can be smaller, lighter and less expensive, because they don't need to produce as large an image circle to cover a APS-C size sensor. For that matter, EF lenses you choose might also be smaller and lighter, especially telephotos. For example, on your T5i a 300mm lens is pretty powerful telephoto. In order to enjoy about the same reach with a full frame camera, you'd have to use approx. a 500mm lens, which will generally be much bigger and heavier... and in many cases a good deal more expensive.
Third party manufacturers don't make EF-S lenses... All theirs simply use the EF mount. But, like EF-S lenses, some are "crop only" designs (Sigma DC, Tamron Di II and Tokina DX, for example). Same as with Canon EF-S and EF lenses, you can use all these on your T5i, as well as third party manufacturers' full frame capable lenses (Sigma DG, Tamron Di and Tokina FX).
Some other important designations you'll find on lenses:
Canon makes three types of autofocus drives: micro motor (no marking on lens), STM (stepper motor) and USM (ultrasonic motor). Canon's USM is the fastest and best for tracking movement, such as sports photography (Sigma's HSM and Tamron's USD are similar). Canon's STM is reasonably fast, very quiet and smooth, especially good for videography (there are no third party equivalent lenses). Micro motor lenses are the least expensive, can be a bit noisier, slower and less capable of tracking (third party lenses using micro motor drives also usually aren't marked, but some use a "Piezo" or PZD indication.)
Canon "IS" lenses have built in image stabilization. (Sigma calls it "OS" and Tamron labels theirs "VC". Tokina has just started making a 70-200mm with VCM-S designation, which means something similar to IS and USM, but isn't available to fit Canon yet.)
Have fun shopping!
***********
Alan Myers
San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7D(x2), 50D(x3), some other cameras, various lenses & accessories
FLICKR & EXPOSUREMANAGER
