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Re: [OM] My hunt for long, fast glass

Subject: Re: [OM] My hunt for long, fast glass
From: "tOM Trottier" <Tom@xxxxxxxxxxxxx>
Date: Mon, 31 Mar 2003 12:57:11 -0500
Since the convertor fits on the front, the maximum aperture it could have 
would be the be the focal length over the width of the front lens.

tOM

On Monday, March 31, 2003 at 17:15
C.H.Ling <olympus@xxxxxxxxxxxxxxx> wrote:

> If the glasses has good coverage (no vignetting) and assume no "glass
> and reflection lost" there will be no light loss for front adapter. As
> in the case of B300 on IS3000 and T-Con 14B on E-10 the lost is
> neglectable, for sure not one stop.
> 
> C.H.Ling  
> 
> Piers Hemy wrote:
> > 
> > Assuming that the convertor has perfect light transmission capabilities, if
> > you double the focal length without doubling the physical aperture, my
> > arithmetic says that the maximum relative aperture must be halved (ie f/2.8
> > becomes f/4).
> > 
> > I don't know the B-300, but let's assume that it does have perfect
> > transmission - I doubt that it doubles the physical aperture!
> > 
> > Piers
> > 
> > -----Original Message-----
> > From: owner-olympus@xxxxxxxxxxxxxxx [mailto:owner-olympus@xxxxxxxxxxxxxxx]
> > On Behalf Of Clemente Colayco
> > Sent: Monday, March 31, 2003 8:25 AM
> > To: olympus@xxxxxxxxxxxxxxx
> > Subject: Re: [OM] My hunt for long, fast glass
> > 
> > Wait, as I recall list members discussed that the B 300 does lead to light
> > loss somehow.
> > 
> > ----- Original Message -----
> > From: <petertje@xxxxxxxxxxxxx>
> > To: <olympus@xxxxxxxxxxxxxxx>
> > Sent: Monday, March 31, 2003 4:14 PM
> > Subject: [OM] My hunt for long, fast glass
> > 
> > >
> > > Hi,
> > >
> > > In the end I settled for an Olympus IS B-300 front convertor.  I won a
> > > bid
> > for one at 142 Euro on eBay last week.  Even though I've never used anything
> > like it, I liked the reviews it gets all over Internet.  And a 150/f2.x
> > sounds cooooool :-)

---------
http://www.CanadianCameraConference.ca  2003 Jun 28-30
tOM Trottier,   ICQ:57647974    http://abacurial.com
        758 Albert St, Ottawa ON Canada K1R 7V8 
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"The moment one gives close attention to anything, 
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awesome, indescribably magnificent world in itself -- 
Henry Miller, 1891-1980


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