10d autofocus and teleconvertor

Discussion in 'Digital Photography' started by Don, Aug 24, 2003.

  1. Don

    Don Guest

    I have a Tamron 28 - 300 lens that contrary to a lot of press I find more
    than adequate for my needs. The autofocus system on the 10d works very well
    even in low light conditions at the 300 end, even with shots without much
    contrast etc. I was wondering if the loss of two light stops will make a
    lot of difference across the board to the autofocus system. Has anybody
    tried a 2x teleconvertor with the Tamron 28 -300 LD IF XR on a 10D? Thoughts
    and views appreciated.

    regards

    --
    Don From Down Under
    Don, Aug 24, 2003
    #1
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  2. Don

    David French Guest

    "Don" <> wrote in message
    news:4P02b.59537$...
    > I have a Tamron 28 - 300 lens that contrary to a lot of press I find more
    > than adequate for my needs. The autofocus system on the 10d works very

    well

    I'm glad you said that, I've just ordered exactly that.
    David French, Aug 24, 2003
    #2
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  3. The 10D needs f/5.6 to focus. Slower f/# than that and it overshoots
    and never achieves focus.

    Roger Clark

    Don wrote:

    > I have a Tamron 28 - 300 lens that contrary to a lot of press I find more
    > than adequate for my needs. The autofocus system on the 10d works very well
    > even in low light conditions at the 300 end, even with shots without much
    > contrast etc. I was wondering if the loss of two light stops will make a
    > lot of difference across the board to the autofocus system. Has anybody
    > tried a 2x teleconvertor with the Tamron 28 -300 LD IF XR on a 10D? Thoughts
    > and views appreciated.
    >
    > regards
    >
    > --
    > Don From Down Under
    Roger N. Clark, Aug 24, 2003
    #3
  4. Don

    Mike Graham Guest

    In article <>, Roger N. Clark wrote:

    > page (Aug 10 images) are with stacked 1.4+2x TCs (Kenko pro 300)
    > and mars has a lot of detail.



    *Stacked* teleconverters? I didn't know you could do that.

    --
    =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
    Mike Graham | Metalworker, rustic, part-time zealot.
    |
    <http://www.metalmangler.com>| Caledon, Ontario, Canada

    Lousy photographer with a really nice camera - Olympus C3020Zoom.
    <http://www.metalmangler.com/photos/photos.htm>
    Mike Graham, Aug 24, 2003
    #4
  5. Don

    Bill Hilton Guest

    >From: "Don"

    >I have a Tamron 28 - 300 lens that contrary to a lot of press I find more
    >than adequate for my needs. The autofocus system on the 10d works very well
    >even in low light conditions at the 300 end, even with shots without much
    >contrast etc. I was wondering if the loss of two light stops will make a
    >lot of difference across the board to the autofocus system. Has anybody
    >tried a 2x teleconvertor with the Tamron 28 -300 LD IF XR on a 10D?


    With the Canon tele-converters this system will autofocus with apertures of
    f/5.6 or wider, so you'd need an f/4 lens to autofocus with the 1.4x t/c and an
    f/2.8 lens to autofocus with the 2x t/c, if using a Canon tele-converter.
    Dunno what the aperture is for your lens but I'm guessing it's not an f/2.8 :)


    You probably can't use the Canon t/c on this lens without the 12 mm spacer, so
    probably you'll be using an off-brand converter. These usually will let the
    body *try* to autofocus (the Canon t/c passes along the info to the body so it
    won't even try) so perhaps you can, perhaps you can't, depending on the
    contrast of the scene. I'd guess it will be very slow with a lot of hunting.

    Bill
    Bill Hilton, Aug 24, 2003
    #5
  6. Don

    Don Coon Guest

    Roger, are you speaking from experience or second hand postings or
    manufacturer specs?

    Reason I ask is that I use a Tamron 1.4x on a Canon 75-300mm at the 300mm
    end. I have absolutely NO problems achieving focus above f/5.6; it doesn't
    "overshoot." I'm beginning to think this "10D needs f/5.6 to focus"
    statement should be classed as an "urban myth." : )

    It would be interesting to hear teleconverter owner's experience. Maybe I'm
    just lucky.

    Cheers



    "Roger N. Clark" <> wrote in message
    news:...
    > The 10D needs f/5.6 to focus. Slower f/# than that and it overshoots
    > and never achieves focus.
    >
    > Roger Clark
    >
    > Don wrote:
    >
    > > I have a Tamron 28 - 300 lens that contrary to a lot of press I find

    more
    > > than adequate for my needs. The autofocus system on the 10d works very

    well
    > > even in low light conditions at the 300 end, even with shots without

    much
    > > contrast etc. I was wondering if the loss of two light stops will make

    a
    > > lot of difference across the board to the autofocus system. Has anybody
    > > tried a 2x teleconvertor with the Tamron 28 -300 LD IF XR on a 10D?

    Thoughts
    > > and views appreciated.
    > >
    > > regards
    > >
    > > --
    > > Don From Down Under

    >
    Don Coon, Aug 24, 2003
    #6
  7. Don

    Bill Hilton Guest

    >From: "Don Coon" coondw_nospam@hotmail_dot_.com

    >Roger, are you speaking from experience or second hand postings or
    >manufacturer specs?
    >
    >Reason I ask is that I use a Tamron 1.4x on a Canon 75-300mm at the 300mm
    >end. I have absolutely NO problems achieving focus above f/5.6; it doesn't
    >"overshoot." I'm beginning to think this "10D needs f/5.6 to focus"
    >statement should be classed as an "urban myth." : )
    >
    >It would be interesting to hear teleconverter owner's experience. Maybe I'm
    >just lucky.


    The f/5.6 min aperture for the Canon SLR's was decided upon by Canon and if you
    use a CANON teleconverter it won't even try to autofocus past f/5.6, except for
    the EOS-3 and I think the 1-V, which will autofocus at f/8 using just the
    center sensor. The body will turn off the af automatically (with a Canon t/c).

    This is with the *Canon* converter line, with an off brand there's no coupling
    between the converter and the body to let the body know a converter is in place
    so it tries to autofocus regardless. If there's enough contrast it can still
    af for a while beyond f/5.6 but apparently Canon made the decision to choke it
    off unless they were pretty sure you can focus reliably.

    For example, with my 500 f/4 lens and a 2x t/c I can autofocus at 1,000 mm and
    f/8 with my EOS-3 (with IS, this is a nice combo :). If I stack the 2x with a
    1.4x I'm at 1,400 mm and f/11 but there's no way for the body to know there are
    two converters attached, so if I leave the AF on it will try to autofocus, and
    occasionally it will work, but often it won't. Basically it's not reliable at
    this aperture and I almost always turn it off as soon as I realize I left it
    on, after a couple of hunting cycles.

    If I put our 400 f/5.6 on the EOS-3 with the Canon 2x (800 mm @ f/11) it won't
    even try to af since the body senses it's at f/11 and disables af.

    As for the 10D, I think everyone assumes that since it's built on the Elan body
    and not the EOS-3 body it would have the same af values, ie, stop at f/5.6 with
    the Canon t/c. I can borrow my wife's 10D and put an f/4 lens on it and try it
    with the Canon 1.4x (f/5.6 ... should af) and 2x (f/8 ... should block af if
    the theory is right). Will try this in a few minutes and let you know.

    Anyway, Roger isn't making this up, it was a decision by Canon to choke off AF
    when they felt there was insufficient light and contrast coming in for
    *reliable* autofocussing.

    Bill
    Bill Hilton, Aug 24, 2003
    #7
  8. Don Coon wrote:

    > Roger, are you speaking from experience or second hand postings or
    > manufacturer specs?
    >
    > Reason I ask is that I use a Tamron 1.4x on a Canon 75-300mm at the 300mm
    > end. I have absolutely NO problems achieving focus above f/5.6; it doesn't
    > "overshoot." I'm beginning to think this "10D needs f/5.6 to focus"
    > statement should be classed as an "urban myth." : )
    >
    > It would be interesting to hear teleconverter owner's experience. Maybe I'm
    > just lucky.


    I have a variety of canon film and dslr cameras and I speak
    from experience. With the kenko pro 300 TCs the canons
    will try and autofocus. If you are using a short focus
    lens with a TC, the system will work at f/8 in my experience,
    but on longer telephotos, like 500mm, the focus system fails
    completely. I've rarely been able to achieve
    autofocus with Canon's 500 F/4 L IS + 2x and never with 1.4+2x.
    But I focus with the 1.4x, then add the 2x (for 1.4+2x)
    on the end and focus is still right on.

    If canon comes out with an more than 8 megapixel dslr
    with focusing at f/8, I'll buy it if in the less than $2500 range.

    Roger
    Roger N. Clark, Aug 24, 2003
    #8
  9. Don

    Don Coon Guest

    "Roger N. Clark" <> wrote in message
    news:...
    > Don Coon wrote:
    >
    > > Roger, are you speaking from experience or second hand postings or
    > > manufacturer specs?
    > >
    > > Reason I ask is that I use a Tamron 1.4x on a Canon 75-300mm at the

    300mm
    > > end. I have absolutely NO problems achieving focus above f/5.6; it

    doesn't
    > > "overshoot." I'm beginning to think this "10D needs f/5.6 to focus"
    > > statement should be classed as an "urban myth." : )
    > >
    > > It would be interesting to hear teleconverter owner's experience. Maybe

    I'm
    > > just lucky.

    >
    > I have a variety of canon film and dslr cameras and I speak
    > from experience. With the kenko pro 300 TCs the canons
    > will try and autofocus. If you are using a short focus
    > lens with a TC, the system will work at f/8 in my experience,
    > but on longer telephotos, like 500mm, the focus system fails
    > completely. I've rarely been able to achieve
    > autofocus with Canon's 500 F/4 L IS + 2x and never with 1.4+2x.
    > But I focus with the 1.4x, then add the 2x (for 1.4+2x)
    > on the end and focus is still right on.
    >
    > If canon comes out with an more than 8 megapixel dslr
    > with focusing at f/8, I'll buy it if in the less than $2500 range.
    >
    > Roger


    Thanks! Now I understand. Makes me feel lucky I bought the Tamron
    converter. Cheaper (by far), shows no degradation of image and no AF focus
    problems.

    Don
    Don Coon, Aug 24, 2003
    #9
  10. Don

    Don Coon Guest

    "dslr" <> wrote in message
    news:...
    > Don Coon wrote:
    > >
    > > Roger, are you speaking from experience or second hand postings or
    > > manufacturer specs?
    > >
    > > Reason I ask is that I use a Tamron 1.4x on a Canon 75-300mm at the

    300mm
    > > end. I have absolutely NO problems achieving focus above f/5.6; it

    doesn't
    > > "overshoot." I'm beginning to think this "10D needs f/5.6 to focus"
    > > statement should be classed as an "urban myth." : )
    > >
    > > It would be interesting to hear teleconverter owner's experience. Maybe

    I'm
    > > just lucky.
    > >

    >
    > I use a 10D, 100-400/f4-5.6L and a Canon 1.4x MkI extender - you have to
    > tape over three pins on the lens (or extender) so that the camera is no
    > longer aware that the extender is present, otherwise it disables the AF
    > completely.
    > That done, I get good AF in anything better than pretty poor light - by
    > pretty poor I mean poor enough that it isn't really worth taking any
    > photos with that length lens anyway.
    >
    > The D30 and D60 would also work the same way with this combination, but
    > the light had to be pretty good to achieve reliable AF - that's the most
    > significant improvement in the 10D for my purposes.
    >
    > --
    > regards,
    > dslr


    What's Canon's reasoning here?? If it works well taping the pins what's
    their logic? Are they simply trying to protect their income from longer
    lenses?

    Don
    Don Coon, Aug 24, 2003
    #10
  11. Don

    dslr Guest

    Don Coon wrote:
    >
    > "dslr" <> wrote in message
    > news:...
    > > Don Coon wrote:
    > > >
    > > > Roger, are you speaking from experience or second hand postings or
    > > > manufacturer specs?
    > > >
    > > > Reason I ask is that I use a Tamron 1.4x on a Canon 75-300mm at the

    > 300mm end. I have absolutely NO problems achieving focus above f/5.6; it
    > doesn't "overshoot." I'm beginning to think this "10D needs f/5.6 to focus"
    > > > statement should be classed as an "urban myth." : )
    > > >
    > > > It would be interesting to hear teleconverter owner's experience. Maybe

    > I'm just lucky.
    > > >

    > > I use a 10D, 100-400/f4-5.6L and a Canon 1.4x MkI extender - you have to
    > > tape over three pins on the lens (or extender) so that the camera is no
    > > longer aware that the extender is present, otherwise it disables the AF
    > > completely.
    > > That done, I get good AF in anything better than pretty poor light - by
    > > pretty poor I mean poor enough that it isn't really worth taking any
    > > photos with that length lens anyway.
    > >
    > > The D30 and D60 would also work the same way with this combination, but
    > > the light had to be pretty good to achieve reliable AF - that's the most
    > > significant improvement in the 10D for my purposes.

    >
    > What's Canon's reasoning here?? If it works well taping the pins what's
    > their logic? Are they simply trying to protect their income from longer
    > lenses?


    I think it's more because it doesn't work "as well" as an f5.6
    combination in "all" conditions. The spec is f5.6 so they are making
    sure that no-one can complain if a camera won't work with an f8
    combination if it's not designed to do so.
    Much the same as putting ISO3200 on the 10D because some users said they
    wanted it, but the quality isn't what Canon would like - hence it's not
    available by default, you have to turn it on yourself.

    --
    regards,
    dslr
    dslr, Aug 24, 2003
    #11
  12. Don

    Jim D Guest

    "Roger N. Clark" <> wrote in news:3F48C504.1C5F16C4
    @qwest.net:

    > The 10D needs f/5.6 to focus. Slower f/# than that and it overshoots
    > and never achieves focus.
    >
    > Roger Clark


    That is not true. Many have reported that th 100-400 with a 1.4 focuses
    just fine when taping the last three pins on the teleconverter.
    Jim D, Aug 24, 2003
    #12
  13. Don

    Tony Spadaro Guest

    It is not a sharp cut off, but 5.6 is the point at which AF begins to
    get unreliable. You can also zoom out to the 75 end and achieve focus then
    zoom in to 300 - the dof should take care of the difference.

    --
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    home of The Camera-ist's Manifesto
    The Improved Links Pages are at
    http://www.chapelhillnoir.com/links/mlinks00.html
    New email - Contact on the Menyou page.
    "Don Coon" <coondw_nospam@hotmail_dot_.com> wrote in message
    news:ue52b.243682$o%2.109758@sccrnsc02...
    > Roger, are you speaking from experience or second hand postings or
    > manufacturer specs?
    >
    > Reason I ask is that I use a Tamron 1.4x on a Canon 75-300mm at the 300mm
    > end. I have absolutely NO problems achieving focus above f/5.6; it

    doesn't
    > "overshoot." I'm beginning to think this "10D needs f/5.6 to focus"
    > statement should be classed as an "urban myth." : )
    >
    > It would be interesting to hear teleconverter owner's experience. Maybe

    I'm
    > just lucky.
    >
    > Cheers
    >
    >
    >
    > "Roger N. Clark" <> wrote in message
    > news:...
    > > The 10D needs f/5.6 to focus. Slower f/# than that and it overshoots
    > > and never achieves focus.
    > >
    > > Roger Clark
    > >
    > > Don wrote:
    > >
    > > > I have a Tamron 28 - 300 lens that contrary to a lot of press I find

    > more
    > > > than adequate for my needs. The autofocus system on the 10d works

    very
    > well
    > > > even in low light conditions at the 300 end, even with shots without

    > much
    > > > contrast etc. I was wondering if the loss of two light stops will

    make
    > a
    > > > lot of difference across the board to the autofocus system. Has

    anybody
    > > > tried a 2x teleconvertor with the Tamron 28 -300 LD IF XR on a 10D?

    > Thoughts
    > > > and views appreciated.
    > > >
    > > > regards
    > > >
    > > > --
    > > > Don From Down Under

    > >

    >
    >
    Tony Spadaro, Aug 24, 2003
    #13
  14. Don

    Boris Harss Guest

    Hi, Don,

    > I have a Tamron 28 - 300 lens that contrary to a lot of press I find more
    > than adequate for my needs. The autofocus system on the 10d works very well
    > even in low light conditions at the 300 end, even with shots without much
    > contrast etc. I was wondering if the loss of two light stops will make a
    > lot of difference across the board to the autofocus system. Has anybody
    > tried a 2x teleconvertor with the Tamron 28 -300 LD IF XR on a 10D? Thoughts
    > and views appreciated.


    Not discussing the quality of the lens ;-)). However, on the long side,
    you are at a 5.6 aperture. If you look at the principal that makes
    Autofocus work, you will realize that Aperture (not only light /
    contrast) is an important parameter. Canon Camras are typically
    specified to work until f/5.6 reliably. This does not mean they stop to
    work at max. apertures smaller than that (especally if you are using a
    "dumb" converter that does not tell the camera the "true" aperture but
    reports the original values). Instead, the accuracy and speed of the AF
    goes down the tubes.

    Is this all theory? I have an EOS 1n film camera that I love for its
    very fast and reliable autofocus (only the 1V might be better). For fun,
    I tried an 1.4 externder (non-Canon) on a 70-300 IS USM, and the results
    were, at best, mixed, if not to say: Random.

    Long speech, short conclusion: Don't spend money on this experiment.

    Cheers,
    B.
    Boris Harss, Aug 24, 2003
    #14
  15. Don

    Jim D Guest

    dy (Bill Hilton) wrote in
    news::

    > Don, I just tested my wife's 10D ... with the 400 f/5.6 L it of course
    > autofocusses fine. I put the Canon 1.4x t/c on it, for 640 mm @ f/8,
    > and the autofocus shuts off, it won't even attempt to af.
    >
    > As I mentioned earlier, with non-Canon t/c's there's no coupling to
    > the body so it will attempt to af even if the min aperture is tighter
    > than f/5.6 like with your Tamron 1.4x, and you'll be able to af or
    > not, depending on the contrast of the scene. Canon arbitrarily
    > decided to cut it off at f/5.6 for this body when using Canon
    > converters though.


    You can tape the last three pins on the converter and it will focus just
    fine.
    Jim D, Aug 24, 2003
    #15
  16. Don

    Jim D Guest

    dy (Bill Hilton) wrote in
    news::

    > You probably can't use the Canon t/c on this lens without the 12 mm
    > spacer, so probably you'll be using an off-brand converter. These
    > usually will let the body *try* to autofocus (the Canon t/c passes
    > along the info to the body so it won't even try) so perhaps you can,
    > perhaps you can't, depending on the contrast of the scene. I'd guess
    > it will be very slow with a lot of hunting.


    Actually they focus just fine.
    Jim D, Aug 24, 2003
    #16
  17. Don

    Nils Rostedt Guest

    "Don Coon" wrote....

    > What's Canon's reasoning here?? If it works well taping the pins what's
    > their logic? Are they simply trying to protect their income from longer
    > lenses?
    >


    My $0.02:
    - avoiding the annoyance of customers who inevitably will try to AF in even
    darker situations, where the AF simply doesn't work anymore
    - protecting the lens from the mechanical wear that occurs when the focus
    "hunts"

    Just guesses. /Nils
    Nils Rostedt, Aug 24, 2003
    #17
  18. Don

    Bill Hilton Guest

    >>"Don Coon" wrote...
    >>
    >> What's Canon's reasoning here?? If it works well taping the pins what's
    >> their logic? Are they simply trying to protect their income from longer
    >> lenses?




    >From: "Nils Rostedt"


    >My $0.02:
    >- avoiding the annoyance of customers who inevitably will try to AF in even
    >darker situations, where the AF simply doesn't work anymore
    >- protecting the lens from the mechanical wear that occurs when the focus
    >"hunts"


    To add to what Nils said, the spec for the 10D says "AF working range: EV 0.5 -
    18 (at 20 C, ISO 100)." EV 0.5 is pretty darn dim.

    By cutting off AF at f/5.6 Canon is trying to insure you'll get reliable AF
    performance in low light levels. I can just imagine the complaining posts on
    this newsgroup if Canon claimed AF at f/8 or f/11 and people found they
    couldn't actually do it in moderately dim light ...

    Bill
    Bill Hilton, Aug 24, 2003
    #18
  19. Don

    Guest

    In message <240820030859156191%>,
    Randall Ainsworth <> wrote:

    >You are free to spend your money on whatever do-dads you please. I
    >choose to avoid teleconverters for a variety of reasons. And I don't
    >know of any of my friends in the photography biz (pros) who use them.



    www.calvorn.com

    An avid bird photographer, has the Canon 600mm f4L IS and 300mm f2.8L
    IS, and uses Canon teleconverters on both and claims they work great.
    --

    <>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
    John P Sheehy <>
    ><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><
    , Aug 24, 2003
    #19
  20. Don

    Don Coon Guest

    "Bill Hilton" <> wrote in message
    news:...
    > >>"Don Coon" wrote...
    > >>
    > >> What's Canon's reasoning here?? If it works well taping the pins what's
    > >> their logic? Are they simply trying to protect their income from

    longer
    > >> lenses?

    >
    >
    >
    > >From: "Nils Rostedt"

    >
    > >My $0.02:
    > >- avoiding the annoyance of customers who inevitably will try to AF in

    even
    > >darker situations, where the AF simply doesn't work anymore
    > >- protecting the lens from the mechanical wear that occurs when the focus
    > >"hunts"

    >
    > To add to what Nils said, the spec for the 10D says "AF working range: EV

    0.5 -
    > 18 (at 20 C, ISO 100)." EV 0.5 is pretty darn dim.
    >
    > By cutting off AF at f/5.6 Canon is trying to insure you'll get reliable

    AF
    > performance in low light levels. I can just imagine the complaining posts

    on
    > this newsgroup if Canon claimed AF at f/8 or f/11 and people found they
    > couldn't actually do it in moderately dim light ...
    >
    > Bill


    Hmmm...... protecting us from ourselves? I'd be pissed if I'd have
    purchased a Canon teleconverter only to find out that Canon crippled it
    instead of simply issue warnings. Hell, stick a label on the damn comverter.
    Thank God I got a Tamron.
    Don Coon, Aug 24, 2003
    #20
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