P3D Re: sharp viewing lens?

[Eric Goldstein <egoldste@xxxxxx>]

Dr T sez:

> I am sorry but my experience does not allow me to agree with these
> statements.  I just sent half an hour looking at a bunch of 7p
> slides in my red button viewer... They look sufficiently sharp
> even right at the edges.

and Rob Labbe concurs:

> I have to agree, but based on my experience of MANY hours on my Kodaslide
> II lenses. When the interocular is set for my eye distance, I am looking
> through the CENTER of the lenses- and there is plenty of area for me to see
> at least 7P of needle sharp resolution.

Needle sharp? The Kodaslide IIs are worse at the extremes of 7 p than
the Red Buttons!

OK, here's an experiment which might help... if you are looking at a 7
perf slide, can you sharpen the corners of the image by racking focus?
Does this then soften focus of the image content in the middle? And if
you are looking at a 5 or 7 perf slide (preferably an RBT with nice hard
edges), does the frame of the window appear perfectly square, or do you
see any bending? Does the window look a bit like a pincushin?


Eric G.


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