RE: [Leica] Wanted .75 Diopter

[Peter Klein <pklein@2alpha.net>]

Richard Clompus wrote:

> With your contact lenses, use the eye with the distance correction.  
> This should give you the clearest image through the viewfinder and
> permit you to get as full a view as possible.  The monovision (near)
> eye won't be of much help for the viewfinder but will permit you to
> read the aperture settings on the lens or shutter speed.

Thanks, Richard.  It's good to be able to discuss this stuff with an
optometrist who is also a photographer!

The above is exactly what I'm doing.  My distance eye is my right eye. It
works well--when I wear the contacts.  Soft contacts are wonderful.
Monovision is wonderful, but it is a compromise.  My distance vision is a
smidge less good than with ordinary glasses. Fine for daytime driving in
familiar territory, but if I'm in the mountains and want to see the
distance scenery at its best, I wear the glasses.  For casual reading--a
quick look at someone else's computer, a menu in a restaurant--the
monovision is fine.  For long periods of reading and computer work, I
devised my own solution--a pair of +1.25 reading glasses with the lens for
the left (close) eye removed.


> Using the top of distance portion of your bifocal glasses will give
> you a clesr view through the viewfinder but will not permit you to get
> your eye close enough to the viewfinder to see the full view.

Again, this is what I've experienced.


> There would be no benefit in using a diopter corrective lens on the
> viewfinder with your glasses or contact lenses.

How does this statement gibe with the one below?

> Use a -0.50 diopter corrective lens mounted onto the viewfinder for
> your distance eye.  Most corrective lenses come in 0.50 diopter
> incremenets. It's better (ie. more comfortable) to be a little bit
> undercorrected than overcorrected.

Now this is interesting.  Are you talking about with contacts, glasses or
neither here?

The above sounds similar to something I've read in the Olympus SLR FAQ,
except that the Olympus FAQ suggests a -2.00 diopter lens. And it's for an
SLR, so it's dealing with a ground-glass screen-not a clear viewfinder.
You can read it at
http://brashear.phys.appstate.edu/lhawkins/photo/olympus.faq.html#ques_P9
If I understand it correctly, The idea is to reduce the image (or increase
the eye relief somehow) so that the photographer can see the whole frame.

One interesting side note to all this.  The elusive Leica 1.25x magnifier
(which is *still* on back order for many of us) is, I believe, a Gallilean
telescope. Don't such devices enlarge in one direction and reduce in the
other?  If so, why doesn't Leica provide it with a thread on each end?
Use it in the magnifying position for a 90 (and 50 if you don't wear
glasses), and reverse it for the 35 and 28.  (And if my profound ignorance
of optics is showing, forget the whole thing... :-)

- --Peter

>Richard Clompus, OD
>Roanoke, VA
>rclompus@cox.net



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