T3D Re: 6X Edmund loupe

[bercov@xxxxxxxxxxx (John Bercovitz)]

My apologies for sending that message to the list instead of to the 
parties for whom it was intended.  I was recently loaned an Edmund 6X 
loupe (#42,769) for testing purposes.  There was some hope that this 
was a 250/f type of 6X since that's how Edmund defines power and 
since for other manufacturers' magnifiers in their catalog they give 
"manufacturer's listed power" which I would infer means 1+250/f.  
Anyhow, when I ran a paraxial calc on the lens's formulation, I got 
49.5 mm and when I put it on the bench and did a nodal slide test, I 
got 49.1 mm.  I think it's a pretty nice lens, though.  Not the 7X 
(figuring by 250/f) we would need for ortho Realist format, but a 
good choice for dual SLRs.  You would have to modify it slightly as 
they've placed the lens group down into the cell a healthy distance, 
probably so you can't get close enough to the glass to see that the 
corners of a 35 mm slide aren't everything they might be.  If you 
remove just a little of the cell, you'll be able to cover 7P easily 
and probably 8P.

John B


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