It is not intended as a "catch" question any more than it is an attempt to "slur" anyone I could classify as an "expert" , which in my case I rather hoped would include the vast majority of readers of Peter's regular binocular lists.
"Reach" is probably no more truly belonging in optical designers' vocabulary than is the term "sharpness" -- my use of which really seemed to annoy another "expert" I recently corresponded with , but I genuinely considered it to be an accepted descriptive term as I have tried to explain it above.
I hope this helps to clarify not only the situation , but my original question.
Regards to all - Kenny .
From: "Craig Buckingham" <buckinghamcraig@___l.com>
Can Peter or Bill or any of the other list members inform me if the
"Universal Binocular Collimator" by Fujinon is a suitable device for the
collimation of high spec binoculars like the Fujinon FMT-SX 7x50 & 16x70.
We have a couple of them being used by businesses in Sydney and I just want
to make sure that I am at least starting with someone that has the right equipment.
Thanks in advance, Craig.
The Fujinon collimator is very capable, if it is manned by a knowledgeable & patient operator.
Back in list #57: 5/5/99, Cory Suddarth (now at a different email) described the Fujinon unit & its complications, as follows:
Subject: collimator v. collimator
From: Cory Suddarth <corys@___a.oriontel.com>
I've got a quandary to post to the group. I have two collimators at my disposal,and while they display similar error levels on binoculars, the claimed error value is very much disputed. Here's the problem.
The U.S. Navy collimator is expressed in ten (10) minute(s) of arc increments, six (6) units equal one (1) degree. This scale then reads six (6) degrees in four (4) quadrants, up, down, side-to-side, the zero point originates in the center. The Fujinon collimator [Universal Binocular Measuring Machine] uses a projected scale that goes through the bino and is displayed on a ground glass screen. Claimed error for these increments are one (1) minute of arc each. Here's where the fun begins.
If I purposely tweak one (1) degree of vertical error (or step) in a pair of 7x50 Swift Seahawks using the Navy Mk V, then place it on the Fujinon collimator, the error should be off the screen of the Fujinon. Vertical error only goes to twenty (20) minutes ,therefore, sixty (60) minutes of arc, or one (1) degree error would not be on this scale, off the chart! Well, this is not the case. One (1) degree of step comes to the tenth place on the Fujinon scale. Question is, if these are indeed one (1) minute of arc, Why does an error of sixty (60) minutes show up as only ten (10) minutes of arc? Off by a factor of six (6)!!
Here, let's try again. This time I will induce an error of only thirty (30) minutes of arc on the Mk V, 1/2 degree error. Now put this on the Fujinon collimator. Theoretically, this error is over the scale limits (by 10 minutes of arc) but should still show up on the screen. Here's where the target falls, it