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Old Dec 25, 2004, 5:52 PM   #1
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Hey guys,

I'm hoping to get the Canon 20D soon. I would like to get the 20D kit to get started off with. BH Photo is selling the kit with either the standard EF-S 18-55mm and one with the EF-S 18-55mm USM lens kit. Is it better to spend a little more money on the ultrasonic motor vs that what I assume on the cheaper lens as using a micro motor? Will there be any more quality? They are both cheap lenses but I am wondering whether to spend a little more on one over the other. Thanks!
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Old Dec 26, 2004, 10:10 PM   #2
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You need to understand there are two types of USM motors. The better RING USM and a cheaper MICRO USM. The "USM" mounted in the 18-55 USM is the MICRO USM, not the nicest ring USM found in the more upscale and even now many consumer Canon lenses. The difference I have seen between micro USM and micro motors is very slight- maybe a little quieter but not necessarily faster. Micro USM is not Ring USM by a long shot- if you ever want to manually focus you'll need to turn the switch from AF to MF just like a non-USM lens. If you want your 20D to utilize the distance portion of ETTL II exposure calculation you need lenses with the RING USM lens motors, which makes me wonder why Canon even sells the 18-55 as a kit lens with the 20D when it does not take full advantage of one of the best improvements in the 20D. Given the choice between 18-55 lenses I would go with the cheaper version. Both will operate about the same. Micro USM is a marketing ploy by Canon more than a real improvement over the micro motor.

Ever seen complaints by those who own the 75-300 IS USM about slow focus? MICRO USM.
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