on 11/11/01 2:24 AM, Wim Verheyen at wimwim@xxxxxxxxxxxxxxxx wrote:
> Hi zuiks and zuikettes,
>
> I could get either an iS/L B-300 1.7 teleconverter or a 2x OM-teleconverter
> for about the same price. I intend to use one of these on my Zuiko 135 f2.8,
> and probably later on a Zuiko 200 f4 (if cash permits).
> According to the esif, both converters will work with both lenses.
> The iS/L converter is very tempting, since it claims no speed loss, in
> contrast
> to the OM. Ok, the OM has a slightly larger magnification.
> What should I do ? (Yep, get both I hear you say ...)
> Is there a hidden catch with the iS/L teleconverter ?
> Has anyone done comparisons between both types ?
> Your advice is highly appreciated.
>
> -----------------------------------------------------------------
> Wim Verheyen, Houthalen, Belgium, wimwim@xxxxxxxxxxxxxxxx
> The Aemit modular analog home, The Kurzweil K2000/K2500 Atomium
> http://gallery.uunet.be/wimwim/
> -----------------------------------------------------------------
Kind of related question... I have the IS/L B-300, and I thought, OK I'll
put this on the 100/2.0 and have a 170/2.0. I had a couple of shots left on
a roll, so I mounted up the 100/2.0 and took a picture... the indicated
exposure (OM-2s on auto) was ~1/250 at f8. Then I screwed on the IS/L and
took another shot, within 15 seconds, of the same scene, and got the
expected 170mm narrower viewpoint. But the indicated exposure at f8 was
about a segment above 1/125... Which would approximately correspond to the
light lost with a 1.7X converter.
My question: What is is about the IS/L converter that makes it 'faster' than
a 1.7X teleconverter put behind the lens? It seems suspect to me, that you
get 'something for nothing' using the IS/L. I know that it has a large front
element; maybe it gathers enough additional light to offset the light lost
in the magnification? But that would be dependent on the specific lens
combination being used. It didn't emiprically seem to work in this instance.
I may experiment further with a full roll of film and a variety of lenses,
but I thought I'd ask for the list's thoughts first.
--
Jim Brokaw
OM-1's, -2's, -4's, (no -3's yet) and no OM-oney...
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