[Leica] SF 20 question

[leicajh at earthlink.net (James Harrison)]

Thanks Mark, I've been away :).  Very sorry to hear about Sal..jh


> [Original Message]
> From: Mark Rabiner <mark@rabinergroup.com>
> To: Leica Users Group <lug@leica-users.org>
> Date: 6/26/2004 1:10:15 AM
> Subject: Re: [Leica] SF 20 question
>
> On 6/25/04 8:20 PM, "James Harrison" <leicajh@earthlink.net> wrote:
>
> > 
> > What is the longest focal lenght M lens that is usable with the SF 20?
> > Thanks in advance.. jh
> > 
>
>
> It's the widest focal length that is limited by a flash unless you put on
> additional diffusion to that flash or bounce it.
> - Not the longest focal length.
> You could put a 1000mm on with a Viso if it could focus close enough to
> reach the flashes range. In other words if the flash could only reach OUT
to
> 10 feet and the very long lens could not go closer IN than 12 which is not
> abnormal then you cant use that flash with that lens.
> And that 2 ft zone in which neither the flash nor the lens reached would
be
> practically nasty; image wise.
> :)
>
>
>
> ...unless you have a thing which do exist to concentrate the flash bean
into
> a narrower beam which would then reach further. Thus optimized more so for
> tele lenes. Some work with Fresnel lens. Invented by Harvey Fresnel.
> :)
> http://hyperphysics.phy-astr.gsu.edu/hbase/geoopt/fresnellens.html
>
>
>
>
> Mark Rabiner
> Photography
> Portland Oregon
> http://rabinergroup.com/
>
>
>
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