Is canon the only maker of EF-S (short back focus) lense?

Discussion in 'Canon' started by peter, Apr 12, 2008.

  1. peter

    peter Guest

    If I understand correctly, a short back focus lense does not need to bend
    light as much to achieve a wide angle lense. And the less you have to bend
    light, the better quality/cheaper the lense is.

    Is canon DSLRs the only ones that supports short back focus lense?

    If yes, does that give canon an advantage in wide angle lenses for non full
    frame sensor DSLR?
     
    peter, Apr 12, 2008
    #1
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  2. peter

    Doug Jewell Guest

    But at the same time, if you have a short back-focus lens,
    the light is hitting the sensor at a greater angle from the
    vertical, and therefore more prone to fall-off.
    I guess to answer that question you need to look at
    available lenses and reviews of them.
    Canon only offer 1 lens wider than 17mm in EF-S (the 10-22).
    All other lenses in the canon line-up that are shorter than
    17mm are EF lenses, so don't offer the short backfocus.

    In a few side-by-side comparisons between the Canon 10-22 vs
    the Sigma 10-20, the cheaper sigma usually comes out on par
    with, or even slightly better, than the Canon lens. The
    sigma is available for all major platforms, and isn't
    short-backfocus. This is probably about the only meaningful
    comparison of a short-backfocus lens vs a regular lens, and
    it would appear Canon gain no benefit from it.

    If you are a name-brand bigot and refuse to put any third
    party lenses on your camera, you will find a better range of
    wide and ultra-wide lenses bearing Nikon and Pentax badges
    than you will find in Canon. Although they are designed for
    the smaller digital sensors, these lenses have regular
    backfocus lengths.

    In the standard kit 18-50'ish range, the Canon (which is the
    only short back-focus model) is reviewed as pretty much the
    worst of the bad bunch.

    So I would conclude then that Canon gain absolutely no
    advantage by having the short backfocus. And if ultra-wide
    in crop-sensor DSLR is your thing, then Canon has the
    poorest range of lenses available.
     
    Doug Jewell, Apr 12, 2008
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  3. peter

    Jufi Guest

    The old one, yes. The newer IS version is very good. Still the same build
    quality, but very sharp.
     
    Jufi, Apr 15, 2008
    #3
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