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Lens Designations


What is the significance of the letter designations which appear on Canon lenses:  EF vs EFS   IS vs IS II   USM vs STM      L?

Do some of these designations indicate features that are only operational on some Canon cameras but not others?





IS ll is a newer & better (IS) Image Stabilizing system, which helps cancel out camera shake


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EF = a lens that will work on any EOS camera with a full frame, APS-H or APS-C sensor.

EF-S = a lens that will only work on an EOS camera with an APS-C sensor.

IS = image stabilization - an electro mechanical system in the lens that counteracts camera shake.

IS II = an improved version of IS.

USM = Ultrasonic Motor - refers to the focusing motor in the lens. USM lenses focus faster.

L = Canon's designation for "pro" quality lenses. L lenses have excellent optical quality, are mechanically rugged and many are weather sealed.

So an L lens is going to be better than a non L lens. Also if you are going to get a Full Frame camera in the future then it would be best not to buy EF-S lenses as they will not work on Full Frame body.

It is difficult to agree with the statement that "an L lens will be better than a non-L lens" unless you define "better" precisely. There are several non-L lenses that are universaly recognized as being of L quality optically including the EF-S 17-55mm f2.8, the EF-S 15-85mm f3.5-5.6 and the 100mm f2.8 macro. It is interesting to note that Canon has never given the L designation to any EF-S lens. Some L lenses are weather sealed but many are not so you cannot make a general statement that L lenses are better in this regard. The closest you can come to making a generaization about L lenses is that they are more rugged mechanically than most other lenses.


I have to agree with that last message. L's are usually considered more rugged & of better quality IQ wise compared to a similar consumer grade lens, but that doesn't always mean we could see an IQ difference short of in a lab test.

"A skill is developed through constant practice with a passion to improve, not bought."
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