Re: [OM] (OM), yes, real OM for a change

[Chuck Norcutt]

If the 170mm (17cm) screw in lens is a close-up lens it's very strong at 
almost 6 diopters.  When I first read this I read it as 170cm rather 
than 170mm or only about 0.6 diopter.  I think a single element lens 
would be OK for such a weak magnification.

The Olympus 49 and 55mm close-up lenses are 40cm or 2.5 diopters.  I 
don't know if the Olympus lenses are doublets (apo) or not.  They 
probably are as I think the Canon and Nikon close-up lenses are also.

Anyhow the 170mm lens is not an Olympus original and is probably much 
too strong for a single element.

Chuck Norcutt


usher99@xxxxxxx wrote:
> Brain Swale writes:

> I located a Zuiko 80mm macro, 170mm screw-in lens for it, and the Zuiko
> macro tube, 


> 
> I didn't realize the FL of the screw -in diopter.  I don't think it is 
> a 2 element apo design.  I don't think Dean was thrilled with the 
> results.
> 
> Mike
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