Lens choice recommendations

Discussion in 'Digital Photography' started by Olin K. McDaniel, Sep 2, 2007.

  1. Several weeks ago I bought the Pentax DSLR K10D camera with the 40mm
    f2.8 "pancake lens" and am delighted with it for the purpose I chose
    it for.

    However, now I'm ready to expand my options and want to buy another
    lens for this particular camera. I want something that has at least a
    telephoto rating of 300mm at a reasonable price. Also I'd like it to
    have at least f 4.0 aperture available.

    In my search, I've found 2 Sigma options - their 28-300mm f3.5 Macro
    at about $279 and their 70-300mm f4 APO DG Macro at about $219. (I'd
    prefer their APO 170-500mm f5 lens, but its cost is too steep for my
    budget at $769.) If someone convinced me to stretch my budget, the
    Tamron AF28-300mm f3.5 at $399 might interest me also, provided it
    might be better on the "tele end" than the Sigma, above.

    SO - I'm asking for any comments/recommendations from ACTUAL
    experience. That experience does not have to be with a Pentax, since
    these lenses are available for Canon and Nikon as well. So, if you've
    actually used one that can ALSO be bought for this Pentas, then let me
    hear from you.

    Also, if someone has another recommendation for a different brand that
    can be "somehow adapted" to the Pentax, I'd like to hear it. It
    should be a reasonably current model with the expected auto features.
    (I already have an older "all manual" one of 80-210mm at f3.8 that I
    bought used recently, and have run many tests with it.) Thus I'm
    ready to expand the use of this new camera from the original purpose
    that I bought it for.

    Olin McDaniel

    To reply by email, please remove "abcd" from Return address
    -----------------------------------------------------
    "Ignorance is treatable, Stupidity is incurable. Sometimes
    the difference is hardly distinguishable, however."
    Olin K. McDaniel, Sep 2, 2007
    #1
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  2. Olin K. McDaniel

    acl Guest

    On Sep 3, 2:38 am, (Olin K. McDaniel)
    wrote:
    > Several weeks ago I bought the Pentax DSLR K10D camera with the 40mm
    > f2.8 "pancake lens" and am delighted with it for the purpose I chose
    > it for.
    >
    > However, now I'm ready to expand my options and want to buy another
    > lens for this particular camera. I want something that has at least a
    > telephoto rating of 300mm at a reasonable price. Also I'd like it to
    > have at least f 4.0 aperture available.
    >
    > In my search, I've found 2 Sigma options - their 28-300mm f3.5 Macro
    > at about $279 and their 70-300mm f4 APO DG Macro at about $219. (I'd
    > prefer their APO 170-500mm f5 lens, but its cost is too steep for my
    > budget at $769.) If someone convinced me to stretch my budget, the
    > Tamron AF28-300mm f3.5 at $399 might interest me also, provided it
    > might be better on the "tele end" than the Sigma, above.


    Hi,
    I have no experience with any of the lenses you mention. However, I
    suspect that their maximum (widest) f/stop changes with focal length
    (so it won't be f/4 at the long end but eg f/5.6 or whatever). So be
    sure to check that before getting any of them. If their specification
    is something like 28-300 f/3.5-5.6, it means that at 300mm it's f/5.6,
    not f/3.5.
    acl, Sep 3, 2007
    #2
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  3. Olin K. McDaniel

    babaloo Guest

    My experience:
    Interesting that you have no interest in moderate to wide angle.
    Realizing that the camera has a 1.6x crop factor you are considering what
    amount to extreme telephoto lenses. Your 40mm has the coverage of about a
    60mm lens for 35mm use with what some would consider the less desirable
    depth of field characteristics of the shorter real focal length.
    You are not going to get a long lens with f4 max aperture at these price
    points, particularly in a zoom. You might want to look for a used fixed
    focal length lens. That would have the highest optical quality.
    The K10d has built in IS but extreme telephoto handheld is asking too much.
    From personal experience I would recommend you look at the Sigma or Tamron
    18-200 lens, although Tamron has a new one that goes out even longer on the
    telephoto end. I have used the 18-200s and optically they are very
    comparable to the far more expensive Nikon 18-200, which I also have
    (several users simultaneously here want lenses of these focal lengths for
    travel, which is why I have first hand experience with these lenses).
    The 18-40mm range covered by the Sigma or Tamron is invaluable for ordinary
    shooting. In that range either lens performs effectively about the same as
    camera brand 18-50 kit zooms. Again, personal experience.
    Perhaps you should widen your horizons.
    babaloo, Sep 3, 2007
    #3
  4. Olin K. McDaniel

    Mark B. Guest

    "Olin K. McDaniel" <> wrote in message
    news:...
    > Several weeks ago I bought the Pentax DSLR K10D camera with the 40mm
    > f2.8 "pancake lens" and am delighted with it for the purpose I chose
    > it for.
    >
    > However, now I'm ready to expand my options and want to buy another
    > lens for this particular camera. I want something that has at least a
    > telephoto rating of 300mm at a reasonable price. Also I'd like it to
    > have at least f 4.0 aperture available.
    >
    > In my search, I've found 2 Sigma options - their 28-300mm f3.5 Macro
    > at about $279


    You missed some of the specs. This lens is actually f/3.5 - f/6.3, meaning
    at 300mm the widest aperture is f/6.3.

    > and their 70-300mm f4 APO DG Macro at about $219.


    This one is f/5.6 max at 300mm.

    > (I'd
    > prefer their APO 170-500mm f5 lens, but its cost is too steep for my
    > budget at $769.) If someone convinced me to stretch my budget, the
    > Tamron AF28-300mm f3.5 at $399 might interest me also, provided it
    > might be better on the "tele end" than the Sigma, above.
    >


    The Tamron is f/6.3 at 300mm. I haven't used any of these lenses, but if
    you're also interested in something wider you might want to look at the
    Sigma 18-200mm f/3.5-6.3 or Tamron 18-250mm f/3.5-6.3. I have the Sigma,
    it's not a bad lens for that range and it travels well (light and compact).

    Mark
    Mark B., Sep 3, 2007
    #4
  5. Olin K. McDaniel

    cmyk Guest

    Hi Olin,

    Here's some links to controlled tests of a variety of lenses, some of which cover the range you're interested in:
    http://www.slrgear.com/reviews/index.php
    http://www.photozone.de/8Reviews/index.html
    Provided you keep the caveats on the latter site about the limitations of comparing 3rd-party lens tests results across different
    cameras in mind, the information from the 3rd-party lens tests for any camera has some applicability for others - the main thing to
    watch for is how any differences in sensor size affect vignetting and distortion and how pixel size affects the Chromatic
    Aberration:pixel size ratio.

    Cheers
    --
    cmyk

    "Olin K. McDaniel" <> wrote in message news:...
    > Several weeks ago I bought the Pentax DSLR K10D camera with the 40mm
    > f2.8 "pancake lens" and am delighted with it for the purpose I chose
    > it for.
    >
    > However, now I'm ready to expand my options and want to buy another
    > lens for this particular camera. I want something that has at least a
    > telephoto rating of 300mm at a reasonable price. Also I'd like it to
    > have at least f 4.0 aperture available.
    >
    > In my search, I've found 2 Sigma options - their 28-300mm f3.5 Macro
    > at about $279 and their 70-300mm f4 APO DG Macro at about $219. (I'd
    > prefer their APO 170-500mm f5 lens, but its cost is too steep for my
    > budget at $769.) If someone convinced me to stretch my budget, the
    > Tamron AF28-300mm f3.5 at $399 might interest me also, provided it
    > might be better on the "tele end" than the Sigma, above.
    >
    > SO - I'm asking for any comments/recommendations from ACTUAL
    > experience. That experience does not have to be with a Pentax, since
    > these lenses are available for Canon and Nikon as well. So, if you've
    > actually used one that can ALSO be bought for this Pentas, then let me
    > hear from you.
    >
    > Also, if someone has another recommendation for a different brand that
    > can be "somehow adapted" to the Pentax, I'd like to hear it. It
    > should be a reasonably current model with the expected auto features.
    > (I already have an older "all manual" one of 80-210mm at f3.8 that I
    > bought used recently, and have run many tests with it.) Thus I'm
    > ready to expand the use of this new camera from the original purpose
    > that I bought it for.
    >
    > Olin McDaniel
    >
    > To reply by email, please remove "abcd" from Return address
    > -----------------------------------------------------
    > "Ignorance is treatable, Stupidity is incurable. Sometimes
    > the difference is hardly distinguishable, however."
    cmyk, Sep 3, 2007
    #5
  6. On Sun, 02 Sep 2007 16:36:06 -0700, acl
    <> wrote:


    >
    >Hi,
    >I have no experience with any of the lenses you mention. However, I
    >suspect that their maximum (widest) f/stop changes with focal length
    >(so it won't be f/4 at the long end but eg f/5.6 or whatever). So be
    >sure to check that before getting any of them. If their specification
    >is something like 28-300 f/3.5-5.6, it means that at 300mm it's f/5.6,
    >not f/3.5.
    >

    Thanks for that "heads up", you are correct and I failed to make as
    careful analysis as perhaps I should. But since this situation exists
    with most of these zoom lenses, I'm still interested in opinions of
    which are the better. Not necessarily the best (meaning the most
    costly) but among the better.
    To reply by email, please remove "abcd" from Return address
    -----------------------------------------------------
    "Ignorance is treatable, Stupidity is incurable. Sometimes
    the difference is hardly distinguishable, however."
    Olin K. McDaniel, Sep 9, 2007
    #6
  7. On Mon, 03 Sep 2007 02:10:55 GMT, "babaloo" <>
    wrote:

    >My experience:
    >Interesting that you have no interest in moderate to wide angle.
    >Realizing that the camera has a 1.6x crop factor you are considering what
    >amount to extreme telephoto lenses. Your 40mm has the coverage of about a
    >60mm lens for 35mm use with what some would consider the less desirable
    >depth of field characteristics of the shorter real focal length.
    >You are not going to get a long lens with f4 max aperture at these price
    >points, particularly in a zoom. You might want to look for a used fixed
    >focal length lens. That would have the highest optical quality.
    >The K10d has built in IS but extreme telephoto handheld is asking too much.
    >From personal experience I would recommend you look at the Sigma or Tamron
    >18-200 lens, although Tamron has a new one that goes out even longer on the
    >telephoto end. I have used the 18-200s and optically they are very
    >comparable to the far more expensive Nikon 18-200, which I also have
    >(several users simultaneously here want lenses of these focal lengths for
    >travel, which is why I have first hand experience with these lenses).
    >The 18-40mm range covered by the Sigma or Tamron is invaluable for ordinary
    >shooting. In that range either lens performs effectively about the same as
    >camera brand 18-50 kit zooms. Again, personal experience.
    >Perhaps you should widen your horizons.
    >
    >
    >

    Thanks for your comments. In all I have over 5 digital cameras, most
    of which have adequate wide angle for my needs. Since this particular
    camera and lens combo was bought primarily for wildlife photography,
    wide angle has little value here. It is used with a Swarovski top end
    spotting scope, which gives 20X to 60X magnification times the 60mm
    equivalent, I'm actually looking for a standalone telephoto lens of
    good quality at something below the resulting 1200mm minimum this
    combo provides.

    And as far as the built in IS, that is an issue that I'm still
    evaluating. Not sure yet if it works as well as claimed or not. Even
    with an old fully manual variable focal length lens I picked up at a
    bargain price.

    Sharpness and clarity are two requirements that are highest in my
    judgment, but without paying extremely high costs.

    To reply by email, please remove "abcd" from Return address
    -----------------------------------------------------
    "Ignorance is treatable, Stupidity is incurable. Sometimes
    the difference is hardly distinguishable, however."
    Olin K. McDaniel, Sep 9, 2007
    #7
  8. On Sun, 2 Sep 2007 23:20:05 -0400, "Mark B."
    <> wrote:

    >
    >"Olin K. McDaniel" <> wrote in message
    >news:...
    >> Several weeks ago I bought the Pentax DSLR K10D camera with the 40mm
    >> f2.8 "pancake lens" and am delighted with it for the purpose I chose
    >> it for.
    >>
    >> However, now I'm ready to expand my options and want to buy another
    >> lens for this particular camera. I want something that has at least a
    >> telephoto rating of 300mm at a reasonable price. Also I'd like it to
    >> have at least f 4.0 aperture available.
    >>
    >> In my search, I've found 2 Sigma options - their 28-300mm f3.5 Macro
    >> at about $279

    >
    >You missed some of the specs. This lens is actually f/3.5 - f/6.3, meaning
    >at 300mm the widest aperture is f/6.3.
    >

    Yep, I responded to that issue in another post.

    >> and their 70-300mm f4 APO DG Macro at about $219.

    >
    >This one is f/5.6 max at 300mm.


    Same as above.
    >
    >> (I'd
    >> prefer their APO 170-500mm f5 lens, but its cost is too steep for my
    >> budget at $769.) If someone convinced me to stretch my budget, the
    >> Tamron AF28-300mm f3.5 at $399 might interest me also, provided it
    >> might be better on the "tele end" than the Sigma, above.
    >>

    >
    >The Tamron is f/6.3 at 300mm. I haven't used any of these lenses, but if
    >you're also interested in something wider you might want to look at the
    >Sigma 18-200mm f/3.5-6.3 or Tamron 18-250mm f/3.5-6.3. I have the Sigma,
    >it's not a bad lens for that range and it travels well (light and compact).
    >
    >Mark
    >
    >

    Thanks Mark. Maybe this is unrealistic, but as just posted, going to
    those wide angle ends is not needed and would seem to risk
    compromising its quality at the telephoto end. So, if not needed, why
    take that risk?

    Olin

    To reply by email, please remove "abcd" from Return address
    -----------------------------------------------------
    "Ignorance is treatable, Stupidity is incurable. Sometimes
    the difference is hardly distinguishable, however."
    Olin K. McDaniel, Sep 9, 2007
    #8
  9. On Mon, 3 Sep 2007 21:12:04 +1000, "cmyk" <> wrote:

    >Hi Olin,
    >
    >Here's some links to controlled tests of a variety of lenses, some of which cover the range you're interested in:
    >http://www.slrgear.com/reviews/index.php
    >http://www.photozone.de/8Reviews/index.html
    >Provided you keep the caveats on the latter site about the limitations of comparing 3rd-party lens tests results across different
    >cameras in mind, the information from the 3rd-party lens tests for any camera has some applicability for others - the main thing to
    >watch for is how any differences in sensor size affect vignetting and distortion and how pixel size affects the Chromatic
    >Aberration:pixel size ratio.
    >
    >Cheers
    >--
    >cmyk
    >



    Thanks, I've read many of those reviews, but not finished them all
    yet. What I saw gave me some good leads, and perhaps helped me avoid
    some also. Will study the rest in more detail later.

    Olin

    To reply by email, please remove "abcd" from Return address
    -----------------------------------------------------
    "Ignorance is treatable, Stupidity is incurable. Sometimes
    the difference is hardly distinguishable, however."
    Olin K. McDaniel, Sep 9, 2007
    #9
  10. Olin K. McDaniel

    cmyk Guest

    Hi Olin,

    In photographic terms, spotting scopes are a poor choice in terms of image quality - their optics just aren't up to anywhere near
    the same standards as a decent camera lens. Chromatic aberrations (purple fringing) tend to be especially severe.

    If you're shooting from a sturdy tripod, IS makes no difference - it can actually degrade an image. IS can make a big difference for
    hand-held shots, though.

    If you're wanting to get around the equivalent of a 1200mm focal length on a 35mm SLR, and you're using a digital SLR with a 1.5-1.6
    FoV crop, then you'll need an actual focal length of 750-800mm. The best combo I can think of for that would be something like a
    Canon/Nikon 100-400 or Sigma 80-400 with a 2x converter; or a Sigma 50-500 or Tamron 200-500 with a 1.4x converter.

    The 400mm lenses with a 2x converter get you out to 800mm, with a maximum aperture of only f11, but you'll still have the benefit of
    IS. The 500mm lenses with a 1.4x converter get you out to 707mm, with a maximum aperture of f9 (with which you'll probably still be
    able to get the AF to work under good lighting conditions), but they don't have IS.

    Of course, if money's no object, Canon can sell you a nice 1200mm f5.6 lens...

    Cheers
    --
    cmyk

    "Olin K. McDaniel" <> wrote in message news:...
    > On Mon, 03 Sep 2007 02:10:55 GMT, "babaloo" <>
    > wrote:
    >
    >>My experience:
    >>Interesting that you have no interest in moderate to wide angle.
    >>Realizing that the camera has a 1.6x crop factor you are considering what
    >>amount to extreme telephoto lenses. Your 40mm has the coverage of about a
    >>60mm lens for 35mm use with what some would consider the less desirable
    >>depth of field characteristics of the shorter real focal length.
    >>You are not going to get a long lens with f4 max aperture at these price
    >>points, particularly in a zoom. You might want to look for a used fixed
    >>focal length lens. That would have the highest optical quality.
    >>The K10d has built in IS but extreme telephoto handheld is asking too much.
    >>From personal experience I would recommend you look at the Sigma or Tamron
    >>18-200 lens, although Tamron has a new one that goes out even longer on the
    >>telephoto end. I have used the 18-200s and optically they are very
    >>comparable to the far more expensive Nikon 18-200, which I also have
    >>(several users simultaneously here want lenses of these focal lengths for
    >>travel, which is why I have first hand experience with these lenses).
    >>The 18-40mm range covered by the Sigma or Tamron is invaluable for ordinary
    >>shooting. In that range either lens performs effectively about the same as
    >>camera brand 18-50 kit zooms. Again, personal experience.
    >>Perhaps you should widen your horizons.
    >>
    >>
    >>

    > Thanks for your comments. In all I have over 5 digital cameras, most
    > of which have adequate wide angle for my needs. Since this particular
    > camera and lens combo was bought primarily for wildlife photography,
    > wide angle has little value here. It is used with a Swarovski top end
    > spotting scope, which gives 20X to 60X magnification times the 60mm
    > equivalent, I'm actually looking for a standalone telephoto lens of
    > good quality at something below the resulting 1200mm minimum this
    > combo provides.
    >
    > And as far as the built in IS, that is an issue that I'm still
    > evaluating. Not sure yet if it works as well as claimed or not. Even
    > with an old fully manual variable focal length lens I picked up at a
    > bargain price.
    >
    > Sharpness and clarity are two requirements that are highest in my
    > judgment, but without paying extremely high costs.
    >
    > To reply by email, please remove "abcd" from Return address
    > -----------------------------------------------------
    > "Ignorance is treatable, Stupidity is incurable. Sometimes
    > the difference is hardly distinguishable, however."
    cmyk, Sep 9, 2007
    #10
  11. On Sun, 09 Sep 2007 03:38:56 GMT, (Olin
    K. McDaniel) wrote:

    >On Mon, 3 Sep 2007 21:12:04 +1000, "cmyk" <> wrote:
    >
    >>Hi Olin,
    >>
    >>Here's some links to controlled tests of a variety of lenses, some of which cover the range you're interested in:
    >>http://www.slrgear.com/reviews/index.php
    >>http://www.photozone.de/8Reviews/index.html
    >>Provided you keep the caveats on the latter site about the limitations of comparing 3rd-party lens tests results across different
    >>cameras in mind, the information from the 3rd-party lens tests for any camera has some applicability for others - the main thing to
    >>watch for is how any differences in sensor size affect vignetting and distortion and how pixel size affects the Chromatic
    >>Aberration:pixel size ratio.
    >>
    >>Cheers
    >>--
    >>cmyk
    >>

    >
    >
    >Thanks, I've read many of those reviews, but not finished them all
    >yet. What I saw gave me some good leads, and perhaps helped me avoid
    >some also. Will study the rest in more detail later.
    >
    >Olin
    >



    OK, a little update on my decision making. After reading many reviews
    and lots of "mfg. propaganda", I had to make a decision on my best
    judgment. Of those I mentioned some interest in, the Tamron seemed to
    come the closest, even if it was the most costly. What the heck, if I
    don't spend it, my heirs will, and that may not be too far down the
    road at age 82. So, I went fot the Tamron, placed the order yesterday
    with B&H and should have it by this Friday.

    Incidentally, Tamron recently released a press statement about a new
    version of this exact lens, but with Image Stabilization built in. I
    was tempted to wait for that, but found out 2 things. It will not be
    offered for the Pentax K10D, since it already has IS in the body. The
    other thing, Tamron announced this week (apparently) that they've
    encountered problems with this item and will not release it yet. And
    B&H confirmed yesterday they don't know when they might get it.
    Further it will cost quite a bit more than the one I just bought!!!

    Hope to have a favorable report soon.

    Olin

    To reply by email, please remove "abcd" from Return address
    -----------------------------------------------------
    "Ignorance is treatable, Stupidity is incurable. Sometimes
    the difference is hardly distinguishable, however."
    Olin K. McDaniel, Sep 12, 2007
    #11
  12. Olin K. McDaniel

    John Turco Guest

    babaloo wrote:

    <heavily edited, for brevity>

    > The K10d has built in IS but extreme telephoto handheld is asking
    > too much.


    <heavily edited>

    Hello, Babaloo:

    The Pentax K100D - not the K10D - features SR (Shake Reduction).


    Cordially,
    John Turco <>
    John Turco, Sep 15, 2007
    #12
  13. Olin K. McDaniel

    Sander Guest

    John Turco wrote:

    > The Pentax K100D - not the K10D - features SR (Shake Reduction).


    John, both the K100D and K10D feature SR.
    The K110D doesn't have SR.

    SR.
    Sander, Sep 15, 2007
    #13
  14. Sorry for being a bit late in responding, but that happens sometimes.
    Anyway, my comments follow yours.


    On Sun, 9 Sep 2007 17:52:01 +1000, "cmyk" <> wrote:

    >Hi Olin,
    >
    >In photographic terms, spotting scopes are a poor choice in terms of image quality - their optics just aren't up to anywhere near
    >the same standards as a decent camera lens. Chromatic aberrations (purple fringing) tend to be especially severe.


    I hate to say so, but I strongly disagree with you here. There are
    "normal" spotting scopes and then there are spotting scopes with ED or
    HD or Fluorite glass, take your pick on what each manufacturer chooses
    to call it. These with this very high quality glass do NOT fit your
    description above, believe me. I have the best in the world when I
    bought it, the Swarovski AT 80 HD. They have upgraded it even further
    since that model, and it sells for between $2000 and $2500 today. At
    the time I bought mine, the Kowa equivalent (with Fluorite glass) was
    on par with it also. Anyhow, there is absolutely NO chromatic
    aberration with the AT 80 HD. And optically it's every bit as good as
    the best camera lenses. Admittedly, It has a couple of drawbacks -
    its closest point of focus is roughly 25 or more feet, and it's heavy
    and inconvenient to carry around, and it's tough to locate a subject
    nestled in the woods or tree tops. And I can't follow a flying bird
    with it.

    >If you're shooting from a sturdy tripod, IS makes no difference - it can actually degrade an image. IS can make a big difference for
    >hand-held shots, though.


    Yep, that's what Pentax tells their customers, although they call it
    Shake Reduction rather than Image Stabilization. Not sure if that
    matters much though. Canon and Nikon have theirs in the lenses,
    Pentax has theirs in the body, and it automatically senses the focal
    length of the lens attached. At least if it's a reasonably modern
    lens.

    >If you're wanting to get around the equivalent of a 1200mm focal length on a 35mm SLR, and you're using a digital SLR with a 1.5-1.6
    >FoV crop, then you'll need an actual focal length of 750-800mm. The best combo I can think of for that would be something like a
    >Canon/Nikon 100-400 or Sigma 80-400 with a 2x converter; or a Sigma 50-500 or Tamron 200-500 with a 1.4x converter.


    Maybe we are confusing each other here. To try to straighten out what
    I tried to say - the spotting scope coupled with the 60mm (equivalent)
    lens of the Pentax, gives me the equivalent of from 1200mm to 3600mm
    focal length, depending on where I set the eyepiece between 20X and
    60X. What I was looking for was a lens that filled in the gap BELOW
    the 1200mm and a standard non telephoto lens. That's why I was
    talking about the 70 to 200 or 300mm options available out there.
    >
    >The 400mm lenses with a 2x converter get you out to 800mm, with a maximum aperture of only f11, but you'll still have the benefit of
    >IS. The 500mm lenses with a 1.4x converter get you out to 707mm, with a maximum aperture of f9 (with which you'll probably still be
    >able to get the AF to work under good lighting conditions), but they don't have IS.


    As stated above, my objective is not to buy a long, long telephoto - I
    already have that with the Swarovski scope. What I wanted was a good
    intermediate range telephoto with variable zoom.

    >Of course, if money's no object, Canon can sell you a nice 1200mm f5.6 lens...


    Since I thought I said I had a Pentax K10D, why would I want to
    consider any Canon lens that would certainly be incompatible?


    >Cheers
    >--
    >cmyk
    >

    Olin McDaniel

    To reply by email, please remove "abcd" from Return address
    -----------------------------------------------------
    "Ignorance is treatable, Stupidity is incurable. Sometimes
    the difference is hardly distinguishable, however."
    Olin K. McDaniel, Sep 16, 2007
    #14
  15. Olin K. McDaniel

    cmyk Guest

    "Olin K. McDaniel" <> wrote in message news:...
    > I hate to say so, but I strongly disagree with you here. There are
    > "normal" spotting scopes and then there are spotting scopes with ED or
    > HD or Fluorite glass, take your pick on what each manufacturer chooses
    > to call it. These with this very high quality glass do NOT fit your
    > description above, believe me. I have the best in the world when I
    > bought it, the Swarovski AT 80 HD. They have upgraded it even further
    > since that model, and it sells for between $2000 and $2500 today. At
    > the time I bought mine, the Kowa equivalent (with Fluorite glass) was
    > on par with it also. Anyhow, there is absolutely NO chromatic
    > aberration with the AT 80 HD. And optically it's every bit as good as
    > the best camera lenses. Admittedly, It has a couple of drawbacks -
    > its closest point of focus is roughly 25 or more feet, and it's heavy
    > and inconvenient to carry around, and it's tough to locate a subject
    > nestled in the woods or tree tops. And I can't follow a flying bird
    > with it.


    That's OK - to each their own. But, if top-of-the-market spotting scopes are so good, why do you suppose professional nature and
    sport photographers don't use them instead of large and expensive camera lenses?

    > Maybe we are confusing each other here. To try to straighten out what
    > I tried to say - the spotting scope coupled with the 60mm (equivalent)
    > lens of the Pentax, gives me the equivalent of from 1200mm to 3600mm
    > focal length, depending on where I set the eyepiece between 20X and
    > 60X. What I was looking for was a lens that filled in the gap BELOW
    > the 1200mm and a standard non telephoto lens. That's why I was
    > talking about the 70 to 200 or 300mm options available out there.
    >

    .....
    >
    > As stated above, my objective is not to buy a long, long telephoto - I
    > already have that with the Swarovski scope. What I wanted was a good
    > intermediate range telephoto with variable zoom.


    OK, but any of the zoom combos I suggested nicely fills out the sub-1200mm range.

    >>Of course, if money's no object, Canon can sell you a nice 1200mm f5.6 lens...

    >
    > Since I thought I said I had a Pentax K10D, why would I want to
    > consider any Canon lens that would certainly be incompatible?


    Well, if money were no object, you probably wouldn't be using the Pentax and could afford both the Canon lens and a body to go with
    it.

    Cheers
    --
    cmyk
    cmyk, Sep 16, 2007
    #15
  16. Olin K. McDaniel

    Educator Guest

    On Sun, 16 Sep 2007 15:57:15 +1000, "cmyk" <> wrote:

    >That's OK - to each their own. But, if top-of-the-market spotting scopes are so good, why do you suppose professional nature and
    >sport photographers don't use them instead of large and expensive camera lenses?


    That's a rather silly question.

    Spotting scopes are hardware and exit-pupil optimized for visual use, so your
    eye can focus its light rays on your retina. They require a few extra scope to
    camera components to make them work together, they don't come with a camera
    mount included. Camera lenses are designed to focus on film or a sensor instead
    of the back of your eye. In fact, decent but not exceptional, spotting scopes
    can be made out of any camera lens by backing it with a telescope (spotting
    scope) eyepiece and the proper spacing and focusing hardware. They used to (or
    still might) sell camera-lens mount adapters just for this purpose. The
    high-quality spotting scope will still win for contrast, clarity, and
    resolution. Due to the longer focal-lengths and fewer lens elements in use the
    objective lens design of the spotting scope is much simpler to be precisely
    optimized for achromatic performance and distortions, to 1/10th wave-length of
    light or even greater accuracy (diffraction limited). Compared to a 7 to15
    element camera lens where they are trying to compact the spotting scope's focal
    length into half or less than that. It also only needs to be able to define one
    large sensor pixel, not be diffraction limited at all f-stops, clearly revealing
    its "slop factor". It's a matter of portability vs. performance. A high-quality
    spotting scope will always win optically. This is even true when comparing
    catadioptric mirrored-lens systems. The more you try to fold the true
    focal-length into a shorter length the more the quality of the image is
    compromised.

    I had the option to obtain a 16" diameter reflector telescope (a single
    objective), vs. a 16" diameter cat. (3 specially ground and complex lensing and
    corrector elements) I easily chose the single-element design because it will
    beat the performance and quality of the image from a more complex (and much more
    expensive) but compact system every time. Price and complexity will never be
    able to compensate for simplicity and eloquence of design. Even the makers of
    Hubble were severely disheartened when they found they'd have to introduce just
    one more lens element into that main mirror's light path to correct for a
    grinding error. Now consider how many lens elements are in your standard camera
    lens. Each one degrades its theoretical focal-length performance just one more
    notch.
    Educator, Sep 16, 2007
    #16
  17. Olin K. McDaniel

    ASAAR Guest

    On Sun, 16 Sep 2007 07:08:41 GMT, Educator, the latest in a long
    line of sock puppet windbag trolls wrote:

    > I had the option to obtain a 16" diameter reflector telescope (a single
    > objective), vs. a 16" diameter cat. (3 specially ground and complex lensing
    > and corrector elements) I easily chose the . . .


    As one of the sock puppet troll clan not known for honesty, why
    should anyone believe that you chose either of those?
    ASAAR, Sep 16, 2007
    #17
  18. Olin K. McDaniel

    cmyk Guest

    "Educator" <> wrote in message news:...
    > Spotting scopes are hardware and exit-pupil optimized for visual use, so your
    > eye can focus its light rays on your retina. They require a few extra scope to
    > camera components to make them work together, they don't come with a camera
    > mount included. Camera lenses are designed to focus on film or a sensor instead
    > of the back of your eye. In fact, decent but not exceptional, spotting scopes
    > can be made out of any camera lens by backing it with a telescope (spotting
    > scope) eyepiece and the proper spacing and focusing hardware. They used to (or
    > still might) sell camera-lens mount adapters just for this purpose. The
    > high-quality spotting scope will still win for contrast, clarity, and
    > resolution. Due to the longer focal-lengths and fewer lens elements in use the
    > objective lens design of the spotting scope is much simpler to be precisely
    > optimized for achromatic performance and distortions, to 1/10th wave-length of
    > light or even greater accuracy (diffraction limited). Compared to a 7 to15
    > element camera lens where they are trying to compact the spotting scope's focal
    > length into half or less than that. It also only needs to be able to define one
    > large sensor pixel, not be diffraction limited at all f-stops, clearly revealing
    > its "slop factor". It's a matter of portability vs. performance. A high-quality
    > spotting scope will always win optically. This is even true when comparing
    > catadioptric mirrored-lens systems. The more you try to fold the true
    > focal-length into a shorter length the more the quality of the image is
    > compromised.
    >
    > I had the option to obtain a 16" diameter reflector telescope (a single
    > objective), vs. a 16" diameter cat. (3 specially ground and complex lensing and
    > corrector elements) I easily chose the single-element design because it will
    > beat the performance and quality of the image from a more complex (and much more
    > expensive) but compact system every time. Price and complexity will never be
    > able to compensate for simplicity and eloquence of design. Even the makers of
    > Hubble were severely disheartened when they found they'd have to introduce just
    > one more lens element into that main mirror's light path to correct for a
    > grinding error. Now consider how many lens elements are in your standard camera
    > lens. Each one degrades its theoretical focal-length performance just one more
    > notch.


    Sounds like a spiel from someone who has little practical knowledge of the subject.

    --
    cmyk
    cmyk, Sep 16, 2007
    #18
  19. Olin K. McDaniel

    DoltDotter Guest

    On Sun, 16 Sep 2007 19:23:49 +1000, "cmyk" <> wrote:

    >Sounds like a spiel from someone who has little practical knowledge of the subject.
    >


    ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^

    Sounds like a typical comment of someone that couldn't even comprehend what was
    being told to them.
    DoltDotter, Sep 16, 2007
    #19
  20. cmyk wrote:
    >
    >
    > That's OK - to each their own. But, if top-of-the-market spotting scopes
    > are so good, why do you suppose professional nature and sport
    > photographers don't use them instead of large and expensive camera lenses?
    >


    Because they are not flat field, at least not without equally
    ultra-expensive field flatteners. Also, if you want to get a long lens
    to focus close without problems (including a huge extension!) you need
    a more complicated design ... thus, $8000 long tele lenses with internal
    focus.

    Doug McDonald
    Doug McDonald, Sep 16, 2007
    #20
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