How good is Canon IS Lens Technology

Discussion in 'Digital Photography' started by Mark Williams, Aug 14, 2006.

  1. Mark Williams

    gypsy3001 Guest

    Prime lens has fixed focal length. Thus, they are easier to design.
    Thus, the lens designers have an easier time optimizing the lens
    elements for better image quality. Thus, they are generally smaller
    than zooms. Thus, the generally have much larger aperture than zoom

    So to give a zoom lens optimized image quality and aperture as large as
    prime lenses, would require an amazing engineering feat. All of the
    lens element will have to be large. Eventually, it would be too costly
    to produce and sell.

    gypsy3001, Aug 16, 2006
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  2. Mark Williams

    SkipM Guest

    I thought of that lens, but the OP was talking about f2.8 zooms, and I got
    stuck there. Of course, that's an awesome lens at that focal length lens
    plus IS...
    SkipM, Aug 16, 2006
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  3. Mark Williams

    Mark² Guest

    That's the lens I now use more than any other.
    Mark², Aug 16, 2006
  4. Mark Williams

    SkipM Guest

    Yeah, but then there's all those focal lengths in between...35mm (he did say
    the ideal would be a 28-200 f2.8 IS...), 50mm, 70mm, 105mm, 135mm...that
    starts to add up, especially if you are looking at fast lenses. Not to
    mention the confusion of deciding which lenses to carry, the bulk if you
    decide to carry more than two and the time spent changing lenses to suit
    changing situations. And a 24mm f2.8 plus a 200mm f2.8 come to $948, not
    that much less than a 70-200 f2.8 non IS.
    SkipM, Aug 16, 2006
  5. Mark Williams

    SkipM Guest

    I can't get it away from my wife long enough to try it out, myself.
    SkipM, Aug 16, 2006
  6. Mark Williams

    ASAAR Guest

    IS may give you 3 more stops, but it's not 3 stops of exposure.
    It allows you to lengthen the shutter speed by up to 3 stops, but
    the exposure stays the same, so the aperture has to be reduced by up
    to 3 stops. Whether this helps or not depends on the lighting, the
    available shutter speeds, apertures, the focal length used and the
    relative motion of objects in the scene. To handle low light
    situations, IS is one tool that can help. Others include sensors
    that allow higher usable ISO values, lenses that have a different or
    greater range of apertures, and bodies that have a different or
    greater range of shutter speeds. None of them (except possibly high
    ISO sensors) provide the best solution in every photo situation.

    With IS and enough light, even if the shutter is slowed by 3 stops
    it may be fast enough to handle objects that aren't moving too
    quickly. In dimmer light, IS may require such slow shutter speeds
    that it would only be useful for taking pictures of stationary
    objects. But if there's a *lot* of light, you might not want to use
    IS, because it might force you to use an aperture too small for your
    purposes, or the lens may not have a small enough aperture to
    produce the correct exposure with the slower shutter speed IS

    Similarly, a faster lens can help in low light situations, but
    again, it doesn't change the necessary exposure. I allows faster
    shutter speeds to be used. Again, there are tradeoffs. Larger
    apertures mean more weight, and a fast lens f/1.4 lens may not have
    the smaller apertures (f/16, f/22, etc.) than a smaller, slower lens
    might provide. This means that it might not be capable of providing
    the correct exposure in very bright conditions, although this could
    be dealt with by using an ND filter.

    Most camera bodies have a sufficiently wide range of available
    shutter speeds. It's mostly cheap P&S cameras that don't have slow
    or very fast shutter speeds, but then, they're not the ones that
    would be in the running for choosing a low light camera.

    Cameras that have very high usable ISOs provide the best all
    around solution for low light shooting. One reason is that higher
    ISOs are added. Low ISOs aren't removed from the low end, so
    picture taking in extremely bright situations doesn't suffer. Most
    cameras have a low ISO within a stop or so of ISO 100. This
    solution is the one that does permit different exposures. So in a
    situation where the proper exposure at 200 ISO would require an
    exposure of 1/15th sec. at f/4, a camera with IS might keep the
    camera steady enough to eliminate noticeable blur from stationary
    objects, but people in the frame that aren't immobile might well
    have blurred faces and hands. The same picture taken without IS,
    but with a DSLR that produces good images at 1600 ISO would be able
    to take the same shot at 1/125th sec. at f/4. Much better for
    stopping moving critters.

    In the end, (I try to avoid saying "at the end of the day" even
    though here it would be more pun-worthy) the best equipment for low
    light shooting would be a fast (wide aperture) lens, with IS (either
    in the body or the lens), and high usable ISO capability. A camera
    with all three of these would be able to get good shots in some
    really low light conditions that might be impossible if only one or
    two of these are available. My own preference would put high ISO as
    the most desirable. Next would come IS, followed by a very fast
    lens. But this isn't a fixed preference. For some types of
    shooting, a large aperture lens would be much more desirable, such
    as with DSLRs that could use them to focus and track much more
    quickly and accurately. Lastly, someone paying big bucks to get a
    camera with good low light capability might have their pictures
    completely outclassed by another photographer using an inexpensive
    P&S that carries a small tripod and knows how and when to use it.
    ASAAR, Aug 16, 2006
  7. SNIP
    A fixed focal length lens may help you in becoming a better
    photographer faster. When you are 'forced' to 'zoom with your feet'
    (consciously choose a perspective and base the focal length on the
    Field of View needed) you'll learn to make better images. Technically
    fixed focal length lenses are easier to optically optimize, so their
    output can be very high quality, for a relatively decent price.

    Zoom lenses almost always constitute an optical/technical compromise.
    They are much more convenient if you are restricted in choosing your
    shooting position, but in general you'll need the more expensive zooms
    to stay happy with their output. A benefit may be that you only need
    one filtersize for a range of focal lengths, so it's more attractive
    to get a higher quality filter.
    Bart van der Wolf, Aug 16, 2006
  8. Mark Williams

    dicktay Guest

    First evenings play with a 17-85 IS F4-5.6. (a new toy) at a nearby railway
    Just trying it out.
    Seem to work ok hand holding ay 1/8 - 1/15 sec at various focal lengths.
    Of course there is subject, but not set, movement visible, however I am
    basically happy with it.
    The original pics, as well as 1024x683, are available via the URL below.
    Hope this helps.
    dicktay, Aug 16, 2006
  9. You could always buy another one....

    David Littlewood, Aug 16, 2006
  10. Mark Williams

    SkipM Guest

    HAH!!! At $1200 a copy, one is all we can afford, right now. I'm NOT
    selling one of our 24-70 f2.8s to pay for it, which is what it would take...
    I'm going to get to use it Friday, working with two girls, I might need the
    IS... <G>
    SkipM, Aug 17, 2006
  11. Mark Williams

    ½ Confused Guest

    You guys are killing me here. If I have this correct,
    you're ALL in agreement that the 24-105 f/4L IS lens
    is the preferred all purpose lens over the 24-70mm.

    (This is the lens we begged for last year and they produced it, no?)

    My parkinsons shake is getting worse. I've been blurring and double
    exposing 1/500 and faster shutter speeds with a 24-70mm f/2.8L lens.
    It didn't take long to realize the problem was me, not the 5D or the
    lens. Now there's a fix. I wonder if an IMAGE STABALIZING lens could
    be justified as a medical necessity...

    ½ Confused, Aug 17, 2006
  12. Mark Williams

    Mark² Guest

    Let's put it this way... I also have a mint 24-70 2.8 L, and it's
    collecting dust.
    If you're serious about parkinsons, then I'm sorry to hear you are dealing
    with that.
    But...I can't think of a better use for IS technology.
    Mark², Aug 17, 2006
  13. Mark Williams

    Bill Funk Guest

    Well, Viagra isn't considered so anymore, but you never know! :)
    Bill Funk, Aug 17, 2006
  14. What great information... Thank you!

    Mark Williams, Aug 17, 2006
  15. I see the error in my logic... I was thinking that the IS feature would
    allow you to shoot at a faster shutter speed. In reading your example and
    other postings, it appears that it does the exact opposite? Since it does
    not increase shutter speed, it does nothing for dim light scenes that has
    motion to stop the blur. Do I have it?
    Mark Williams, Aug 17, 2006
  16. Mark Williams

    SkipM Guest

    I'll let you know how it progresses! But if you include the one chasing me
    to get the lens back, that would be three women...heheheh.
    SkipM, Aug 17, 2006
  17. Mark Williams

    SkipM Guest

    As an interested observer (see above note about my wife's selfishness! <G>)
    I'd have to say that the 24-105 is a better walkabout lens than the 24-70.
    It is marginally lighter, smaller in diameter (although it uses the same
    dia. filter) and shorter, and it does have IS.
    Actually what we (at least Mark and I) begged for was a 24-70 or 105 f2.8L
    IS, but f4 will do, I guess...
    SkipM, Aug 17, 2006
  18. Mark Williams

    ASAAR Guest

    You're welcome. So far my digital cameras have had neither IS,
    high ISO capability nor a fast lens. My next camera will have at
    least one of these, but which of these it will be I don't yet know.
    ASAAR, Aug 17, 2006
  19. Mark Williams

    Mark² Guest

    IS is all about reducing blut that is the result of CAMERA movement in one's
    hands...not subject movement.
    This is why IS is such a boon to those who don't (or can't in some
    circumstances) use a tripod. It allows you to hand-hold at slow
    shutterspeeds that would otherwise introduce unacceptable camera-motion
    Mark², Aug 18, 2006
  20. Mark Williams

    Mark² Guest

    I do wish they had made a 2.8, but I don't miss the bulk and weight that
    surely would have come with it. I WOULD have bought and carried it...but I
    still don't miss the weight. Oh well... You can't have everything, I
    guess. Most "walk-around" uses don't usually require 2.8, though of course
    it's always nice having a bright viewfinder and faster focus. The funny
    thing is, many newer folk buy a 2.8 lens...and then complain that "there's
    something wrong with my lens" -because most of their images are
    blurry...when the real reason is that the typical new person has no
    understanding about DOF, and how allowing your camera to shoot at 2.8 much
    of the time leads to what they perceive as focus issues. :) I have a
    friend whose first digital was the 10D with the 16-35 2.8 L. He would
    always complain that his camera doesn't take pictures that are in focus. So
    finally I examined some of his pictures at 100% on his own computer and
    demonstrated that his pictures were indeed "in focus"...but only at the
    small portion of the frame where he'd centered the active focus point. -The
    rest of the frame was usually fuzzy due to a thin 2.8 DOF. :) I honestly
    wonder sometimes if Canon isn't perhaps quite happy to keep their "2nd tier"
    L lenses (the f4 series) at f4, if for no other reason than to keep new folk
    from getting horrible results with too narrow a DOF as they mindlessly snap
    away on "P"...or "GREEN" mode. :)
    Mark², Aug 18, 2006
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