HSM, USM....Speed?

Discussion in 'Photographic Discussions' started by eravedesigns, Mar 1, 2008.

  1. eravedesigns

    eravedesigns TPF Noob!

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    Hey TPF,

    I was wondering does the sigma HSM lenses and Canon USM lenses really help with speed or is it just something the companies advertise. I always thought and was told that USM and HSM was all about a quite lens and not so much speed.

    Thanks


     
  2. Garbz

    Garbz No longer a newbie, moving up!

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    Yes. There's only so much torque a standard rotary motor can move through a gear set. The piezo electric motors used in USM and AF-S lenses have the advantages of generating insane torque from a tiny size. Coupled with correct gearing it can move the elements much faster. Frankly I couldn't care less about noise.

    The MicroNikkor 105mm f/2.8 AF D takes about 1.5seconds to go from one focusing extreme to the other.
    The MicroNikkor 105mm f/2.8 AF-S G takes about half a second.
     
  3. Antithesis

    Antithesis No longer a newbie, moving up!

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    I just picked up an HSM lens, and when comparing it to my 50mm AF, it's worlds faster. I was playing around in my front yard taking pics of tweety-birds in and around the birdfeeder, and it could switch between subjects with about a 5-10 foot distance between them (like depthwise), and it was pretty much instantaneous and very quiet. Shooting between branches on continous AF is a little tricky though, it tends to jump back and forth very quickly as stuff passes between your subject and the lens.
     
  4. keith204

    keith204 No longer a newbie, moving up!

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    I have the Sigma HSM on one lens, and Canon Ring USM on another. Switching between the two lenses, I don't notice much (if any) difference in the focus speed. I honestly haven't noticed any difference, but I'm sure there is some...just not noticeable for me at least.
     
  5. Alex_B

    Alex_B No longer a newbie, moving up!

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    Well, it always depends on the particular lens, but on average I guess USM /HSM lenses are faster with focusing.

    Anyway, I personally think the noise of some non-USM lenses can be annoying. I once had one that sounded like a chainsaw on speed ;)
     
  6. keith204

    keith204 No longer a newbie, moving up!

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    **I want to take this back. Last night, I actually tested my lenses side-by-side. 2 HSM lenses, 1 USM lens. According to my tests, the USM worked much faster. I'm pretty hacked, since finding this out.
     

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