BirdForum is the net's largest birding community dedicated to wild birds and birding, and is absolutely FREE!

Register for an account to take part in lively discussions in the forum, post your pictures in the gallery and more.

Reply to thread

Message: <blockquote data-quote="Kevin Purcell" data-source="post: 1345455" data-attributes="member: 68323">The dual diopter system (what Steiner call "Dual Precision Setting") is related to two other Steiner features: <ul> <li data-xf-list-type="ul">Fast Close Focus changes the focus speed under 20m (so you can focus more quickley in that tange for a given amount of knob rotation).</li> <li data-xf-list-type="ul">Distance Control is a system they have were you can read the range of the focused object from the markings on the focus knob. Minox have a similar system on one of their bins.</li> </ul>So both of these systems would work perfectly for an emmetrope (a person with perfect vision) or a person with fully corrected vision (i.e. wearing their glasses with a current prescription). But what if you are a myope (near-sighted) or a hyperope (far sighted) not wearing glasses? A myope would focus a distant target beyond their infinity mark on the dial. Conversely a hyperope would focus a distant target closer than the infinity mark on the dial. And similarly all ranges would be incorrect. Sorta negates the feature. So you need to provide a feature that adjusts the bin so that a in focus distant target is set at infinity. They could do this in two ways. One is to allow the dial and the focus setting to move independently by adding a clutch between the dial and the knob (i.e. you don't put the markings on the knob). Then you set the dial to infinity with the knob, flip a level to open up the clutch (so the dial doesn't move) then you can focus on infinity then engage the clutch and your distance dial nove measures correctly. I think this is the Minox route. The other (the Steiner route) goes along these lines: you already have to provide one "diopter adjustment" to compensate for different eye strengths and we know how to make those so why not just provide two "diopter adjustments". One for each eye then you use each of them to compensate for the required eye strength at infinity.You use their adjustment procedure (which is very close to the usual procedure) which is basically setting the infinity positions and compensating for differences between the eyes prescriptions.From this Steiner PDF<a href="http://www.aronsen.no/Inc/GetFile.asp?id=97" target="_blank">http://www.aronsen.no/Inc/GetFile.asp?id=97</a>So I can't see it as a huge win but it does get you close fast focusing in the right range (which is useful) and (optionally) a range dial (not so much).Of course my favorite bit is Just point those Steiner bins at a "Little Brown Job" and you'll know what it is. Birding has never been so easy <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite2" alt=";)" title="Wink    ;)" loading="lazy" data-shortname=";)" /></blockquote>

Verification