Difference between USM and non-USM EF75-300mm f/4-5.6 III

Discussion in 'Digital SLR' started by Isaiah Beard, Jul 24, 2006.

  1. Isaiah Beard

    Isaiah Beard Guest

    I'm in the market to get an EF75-300mm f/4-5.6 III lens for my 30D.
    However, I'm seeing two versions of this lens being sold: a USM version,
    and a non-USM version.

    For reference:

    http://tinyurl.com/rxbql <- DC Motor driven version
    http://tinyurl.com/r7lhd <- USM version

    The only apparent difference between the two (other than about $10 in
    price) is the drive motor. Oh, and the non-USM version is not sold in
    Japan; it is "only sold overseas" (meaning every other market including
    the US). Everything else is almost identical; they even weigh the same.

    Now, I know one main advantage to USM is that they are virtually silent,
    and I also know this firsthand because my 30D came with a non-USM kit
    lens and I bought an additional USM macro for it; the noise difference
    is VERY noticeable. The kit lens isn't raucous or anything, but the
    macro lens absolutely CANNOT be heard in operation at all, at least by
    human ears anyway.

    But, are there any other differences I should be aware of? Is the USM
    motor more durable? Is there a reason I should stay away from DC motor

    For the record, I'm mostly likely buying the USM lens anyway; it's just
    ten bucks extra from B&H. It just piqued my curiosity that Canon would
    sell the exact same lens with USM being the only difference. If the USM
    price difference is so minimal in comparison to the cost of camera and
    lenses, why even bother with a non-USM version?

    [Or, is it a mistake for me to the buy the USM lens, and I should
    isntead go with the DC Motor?]
    Isaiah Beard, Jul 24, 2006
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  2. Isaiah Beard

    Bill Guest

    Be forewarned that the 75-300 is not a very good lense and is generally
    considered a dog among informed users. It lacks sharpness, contrast, and
    colour, it has a slow focus system, and it's not much of a match to the
    excellent 30D.

    Remember, the glass forms the image. The camera body merely records that
    image. The better the lense on the front, the better the image quality.

    No offence, but if you're going to spend that much on a nice camera, why
    cheapen it with a mediocre lense?
    Get the USM version if it's only $10 more. It won't work any better or
    worse, but at least it'll be quiet.
    There are three types of motors for Canon EF lenses:

    DC is the standard direct coupled motor.

    USM is the near-silent motor similar to DC.

    Ring-USM is the near-silent motor that allows simultaneous manual and
    automatic focus. This motor is also MUCH faster than the other two. It
    usually comes with internal focusing which means the front element does
    not rotate.

    The Ring-USM is the best motor, and personally the only worthy choice
    for high quality lenses.

    My suggestion for a good telephoto zoom would be the excellent 70-200
    f/4 L model. It costs more than the 75-300, but it's worth it. There are
    several other models you could consider also.

    Do you have a budget or intended use?
    Bill, Jul 24, 2006
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  3. Isaiah Beard

    G.T. Guest

    And add in a 1.4x teleconverter.

    G.T., Jul 24, 2006
  4. Isaiah Beard

    Neil Guest

    Agreed. I had a 75-300 and hated it! The 70-200 f/4L is a great lens,
    save your money and get one of these instead. You won't regret it.



    Neil, Jul 24, 2006
  5. Isaiah Beard

    Bill Funk Guest

    I had a 75-300 EF lens, and it was OK in good light.
    I now have the newer EF 70-300 IS and it's better all the way around,
    though not an L lens, as others are recommending. It's also not
    anywhere near as expensive. :)
    If you're determined to get this lens, though, $10 is cheap over the
    expected life of the lens.
    Bill Funk, Jul 25, 2006
  6. Isaiah Beard

    Ken Ellis Guest

    On Mon, 24 Jul 2006 17:33:21 -0400, Isaiah Beard

    2 cents worth
    the canon 75-300 USM "IS" 4-5.6 is a good "value" lens and
    a nice walk around (though heavy). The "IS " part is the salient.
    I enjoy mine. I want a better one. It's gonna cost.
    Ken Ellis, Jul 28, 2006
  7. Isaiah Beard

    AaronW Guest

    70-300/4-5.6 IS is better. Or 200/2.8.
    My 4 USM lenses are NOT that quiet, and NOT that much quieter than my 2
    non-USM lenses. If my lenses offer non-USM versions and if those are
    MUCH cheaper, I'd save the money.
    Maybe because that lens is very cheap. It is marketed to people wanting
    to pay a very low price. And later they put in a cheap USM for people
    who want "Ultrasonic" printed on the lens.

    AaronW, Jul 29, 2006
  8. Isaiah Beard

    Bill Guest

    Which USM motor do you have in your lenses?

    The micro-motor USM is only slightly more quiet than the regular motors.
    However the ring-USM motors are silent except for the racking noise as
    the elements slide back and forth.

    The speed of the ring-USM motors is much faster than the others, plus it
    usually offers internal focusing so the front element doesn't rotate.

    If I have the option of a regular USM or ring type, I will always go for
    the ring motor.

    Nikon has the same thing with their AF-S internal motors where they have
    a regular AF-S focus motor in the cheaper lenses, and the much faster
    Silent Wave Motor (SWM) which is ultrasonic like the Canon motor.
    Bill, Jul 29, 2006
  9. Isaiah Beard

    Bill Funk Guest

    I have had two non-USM Canon lenses ( the kit lens and the 75-300
    f/4-5.6) and have three USM lenses (17-40mmL, 28-135 IS, and 70-300
    IS), and the USM lenses are faster and much quieter. I don't
    understand why yours are as noisey as the non USMs.
    Bill Funk, Jul 29, 2006
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