On 11/19/2013 11:29 PM, Jeff Liebermann wrote:
On Tue, 19 Nov 2013 20:06:51 -0600, amdx wrote:


I'm thinking about buying these: http://tinyurl.com/npbcgdx

Those are binoculars suitable for distance viewing. You can get a
clue as to their effectiveness by comparing their size to that of a
real pair of 7x35 binoculars.

Quality is not such a big issue with me because they would only be for
occasional use - and not for that long a time each use.

Cheap and simple optics usually result in some form of aberration.
Chromatic (color) distortion, poor depth of field, wrong viewing
distance, dim image, etc. You can't really tell the difference
between quality and junk until you've made a side by side comparison.

The advertising verbiage is confusing, it says "Eye Jeweler Watch
Repair" and "Required by fishing enthusiasts" and "to ensure a distance
of 400-500 meters" I don't believe this item can focus at 16" and 300Ft/

That makes sense if you realize that they're wearable distance
binoculars, no close up magnifiers.

I'm hoping Jeff Lieberman sees this and gives his input. I don't
know optics.

Hay, spel my nayme correctlee.

Hey mann, I'm really sorry, do you give 1/2 credit for getting the ie
in the correct order? I only got that right because I checked.
Sorry.


I only know enough about optics to get myself in trouble. Please
double check whatever I claim.

I do know my optivisor is good at 8", but it's hard to work
at 8".

This video gives some good advice on the Optivisor:
http://www.youtube.com/watch?v=OwnLeL3jGco
You have the wrong magnification and need to pick the distance at
which you plan to work first, which sets the magnification.

I have two optivisors, two different powers, plus an optiloupe on one.
Oh, and I where a 4.25 diopter contact lens and a 2.25 pair of reading
glasses.


Time for you drag yourself down to the drug store reading glasses
display. Bring a tape measure and some reading material. What you
want to do is pick a specific power of lens and measure the distances
where the image remains in focus (depth of field). High power glasses
will focus over a short distance and will need to have the reading
material fairly close to your eyes. Low power works over a larger
range of distances and farther away from your eyes. Make a chart and
nail it to the wall. Don't bother trying to find a "typical" chart on
the internet as the depth of field varies with your eyes. If you have
astigmatism, like me, it can be rather atypical. There are also
different definitions of diopters as well as "conventional" and
"maximum" magnification.

I buy my glasses ten at a time from the dollar store. (2.25D) I buy
them so I can sit in my computer chair and see the screen. I can't sit
back very much though or I can't focus, but I want 2.25D because I can
also read a book or paper.

I recently bought a set of binocular type glasses to watch Texas
Holdem Poker. I could not make out the percentages graphic on the
screen. With the lenses at 10ft/11ft I can see all the tv screen but
not much more, but I can easily read the percentage graphic. Any closer
than 10ft and it is difficult to focus. I popped $140.00 for them.
The same company makes a pair that focuses at about 16 inches, I'll
probably end up with a pair of those too.
Mikek