canon cameras

[lycan]

Question do canon dslr cameras all come with a built in drive for auto focus of the lenses .I ask cause I know some of the Nikons dont .and what canons do or dont have drives built in thanks for the help

[OsmosisStudios]

All Canon EOS lenses have a motor in them; none of the bodies do. This is the system Nikon is moving towards.

[Preeb]

They all have a focus motor in the lens, but there are a couple of different types. The USM (ultrasonic motor) is the most desirable.

[WolfHeart704]

Originally Posted by Preeb

They all have a focus motor in the lens, but there are a couple of different types. The USM (ultrasonic motor) is the most desirable.

There are two types of USM, though. Ring USM and micro USM. Micro USM is better than your standard autofocus, but not by all too much. Its slightly faster and quieter, but the Ring USM is the real prize. Its virtually silent and much faster. They don't distinguish right on the lens so if your not sure, a quick google search will answer your question.

[Doug Pardee]

Originally Posted by WolfHeart704

They don't distinguish right on the lens

Not in so many words, but a Canon lens has Ring USM if, and only if, all of the following conditions are met:

1. The lens says "USM" (also recognizable by the gold band around the front of the lens),
2. the lens has a focus-distance scale, and
3. the lens is not the 50mm f/1.4.