Re: Good place to get used Olympus lenses?

Discussion in 'Digital Photography' started by Andreas Schmidt, Apr 1, 2004.

  1. John Navas <> wrote in message news:<gLEac.2875$>...
    > [POSTED TO rec.photo.digital - REPLY ON USENET PLEASE]
    >
    > In <> on 30 Mar 2004 21:48:14
    > -0800, (Andreas Schmidt) wrote:
    >
    > >John Navas <> wrote in message news:<vehac.2663$>...

    >
    > >> >There is no focal length multiplier in the adapter.
    > >>
    > >> It's in the system (due to the small size of the sensor), and is high
    > >> enough (along with image quality issues) to greatly diminish the value
    > >> of such an adapter.

    > >
    > >Well, the angle of view becomes smaller, but still there is no focal
    > >length multiplication.

    >
    > The image circle of Four Thirds (on which the E-1 is based) is about 1/2 that
    > of 35mm, so the focal length of a 35mm lens is multiplied by about 2 (the
    > reciprocal) **in 35mm terms** when mounted on a body with a 4/3 sensor; e.g.,
    > a 35-70 zoom becomes a 70-140 zoom in 35mm terms.


    Your description of the result is correct, but you are misusing terms.
    Focal length is a physical property of the lens and is independent on
    format of the film or sensor behind it. Your 35-70mm zoom will always
    have a focal length of 35-70mm, but the resulting angle of view on an
    E-1 will be about the same like a 70-140mm zoom on a 35mm camera.

    It may look as just a matter of terms, but then when you write that
    the OM to E-1 adapter provides focal length multiplication it becomes
    plain wrong and confusing for people who do not know the adapter.
    Because there are indeed adapters, which require a lens, like e.g.
    those for adapting Canon FD lenses to EOS bodies. These adapters do
    have a focal length multiplication, i.e. they work as light
    teleconverters. The OM to E-1 adapter does not.

    > >But why do I write this, just spoiling the second-hand
    > >prices...?

    >
    > Because relatively few photographers come here? ;-)


    I didn't want to say that...

    Andreas
    Andreas Schmidt, Apr 1, 2004
    #1
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  2. Andreas Schmidt

    John Navas Guest

    [POSTED TO rec.photo.digital - REPLY ON USENET PLEASE]

    In <> on 31 Mar 2004 19:00:16
    -0800, (Andreas Schmidt) wrote:

    >John Navas <> wrote in message news:<gLEac.2875$>...


    >> The image circle of Four Thirds (on which the E-1 is based) is about 1/2 that
    >> of 35mm, so the focal length of a 35mm lens is multiplied by about 2 (the
    >> reciprocal) **in 35mm terms** when mounted on a body with a 4/3 sensor; e.g.,
    >> a 35-70 zoom becomes a 70-140 zoom in 35mm terms.

    >
    >Your description of the result is correct, but you are misusing terms.
    >Focal length is a physical property of the lens and is independent on
    >format of the film or sensor behind it. Your 35-70mm zoom will always
    >have a focal length of 35-70mm, but the resulting angle of view on an
    >E-1 will be about the same like a 70-140mm zoom on a 35mm camera.


    Of course, but the whole point of language is to communicate, which "focal
    length multiplier" does. And I'm in good company:

    <http://www.dpreview.com/learn/?/Glossary/Optical/Focal_length_multiplier_01.htm>:
    "Focal Length Multiplier"

    <http://www.imaging-resource.com/PRODS/ND100/D10P.HTM>:
    "focal length multiplier"

    <http://www.lonestardigital.com/multipler.htm>:
    The "Multiplier Effect"

    <http://www.dcresource.com/reviews/canon/eos_10d-review/index.shtml>
    "multiply the lens focal length"

    <http://www.steves-digicams.com/2003_reviews/10d.html#specs>:
    "focal length conversion factor"

    I think that last is arguably the best term, so I'll try to remember to use it
    in the future.

    >It may look as just a matter of terms, but then when you write that
    >the OM to E-1 adapter provides focal length multiplication it becomes
    >plain wrong and confusing for people who do not know the adapter.


    I didn't write that -- I actually wrote:

    The other obvious limitation is the focal length multiplier.

    in response to:

    >... I know the Oly OM lenses are supposed to work fine. I believe that you
    >have to use manual focus only and stopped down metering (not sure about
    >the metering).


    I think it's pretty clear I was referring to the use of OM lenses on the E-1,
    not the teleconverter itself, but I made that even more clear in a follow-up
    response.

    >Because there are indeed adapters, which require a lens, like e.g.
    >those for adapting Canon FD lenses to EOS bodies. These adapters do
    >have a focal length multiplication, i.e. they work as light
    >teleconverters. The OM to E-1 adapter does not.


    True, but the use of OM lenses on the E-1 does, and that's what I was
    referring to.

    Are we done now??

    --
    Best regards,
    John Navas
    [PLEASE NOTE: Ads belong *only* in rec.photo.marketplace.digital, as per
    <http://bobatkins.photo.net/info/charter.htm> <http://rpdfaq.50megs.com/>]
    John Navas, Apr 1, 2004
    #2
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