The message copied below gets me thinking about what "power" means when one speaks of loupes or "magnifiers". Its relevant to know this because, rather than using "loupes" for focusing, one can or might and maybe even should use high quality occulars that can sometimes be converted to focus on a ground glass screen on 35 mm cameras. I should think that even an average"occular" would be far superior , optically, to typical loupes of the type sold by photo stores. The latter are full of abberations and uncorrected errors. I think the equivalent focal length of the eye is about 50mm, and is it true that a 5 mm eyepiece therefore is a loupe or magnifier of 10 (50 divided by 5) power? That's what I remember fom my kindergarden optics class taken in the paleolithic age. glenn shaw ----- Original Message ----- From: Gene Horr Sent: Thursday, February 28, 2002 2:13 PM To: astro-photo@seds.org Subject: Re: [APML] Magnification Larry McManus wrote:
>
> I have a 10x loupe I use to focus right off my cameras focusing screen. I am
> looking for a source for bigger magnifiers 20 -30x. Anyone have a source?
Takahashi makes both a 40X and a 60X focusing microscope. I use the
60X on both a ground glass slide placed on the film rails as well as
on the focusing screen for a Mamiya 645. It should work great for
what you are wanting to do.
As with most Tak parts, it isn't cheap. But it is well made and works.
You might also want to read through Dick Greiner's web site (sorry, I
don't have the address here at work, but a search for "Doc G" should
turn it up) about focusing tools and methods.
Gene Horr
genehorr@texas.net
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