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Archives of an email list on the history of binoculars. - page 98 / 150





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Subjekt: Marox 8x32

From: l.helling@___ne.de (Lothar Helling)

  The plastic knob on top of the central hinge works very well as a stay at the forehead. The binocular than is more stable. I don´t know if this is the original funktion. The dealer I bought my Marox said so. However - it works.

Best regards, Lothar


Subject: Moeller Wedel Marox

From: "Frederick Schwartzman" <jurisfred@___bal.net>

   Dear Guus:   I have the same Marox and I too have wondered about the function of  that center knob. I note that the knob turns up and down but nothing happens. It  does not tighten or lock the interpupillary setting and has nothing to do with  focus. The only thing I could think of was that it might be a rest or brace  against the bridge between the eyes and the raising and lowering function would  accommodate different facial configurations. However, I cannot really believe  that that was the function. Please let me know if you receive any  additional information on the subject.

   Regards,  Fred


Subject: Exit Pupil Diameter and Sharpness

From: "Tim Stevens" <stevptm@___ink.net>

   In Binocular List #273, Kenny started a dialog on  the subject of the relationship between exit pupil diameter and  "sharpness".  In #275 and #277, Rafael and William Cook responded, and in  #278 Kenny replied.

  All this discussion related to the relationship  between exit pupil and sharpness stimulated me to study two texts (the  Handbook of Optics and Smith's Modern Optical Engineering) to see what I  could figure out about this subject.  I concluded that if the optics are  perfect, the exit pupil needs to be 4mm and that if the optics are corrected to  the Rayleigh Quarter Wave Limit, then the exit pupil needs to be 5mm.   There is just not enough space available here to explain how I arrived at these  numbers and (just as important) what assumptions I used to arrive at these  numbers.  However, if you e-mail me at stevptm@___ink.net, I will be happy  to e-mail you my detailed analysis (1.4 MB due to embedded  graphics).  If you want a hard copy, then e-mail me your mail address and I  will mail you a hard copy of my analysis.

  Tim Stevens  "binonut"


Subject: Fuji UBMM, collimators

From: gordiray@___t

  Why don't you make one, following Hanna in ATM  books.?  After a tree grew, I lost my infinity target for an otherwise Navy style setup.  I have sketched over a dozen setups using mirrors, but have not yet built one.  Tilted spherical mirrors give  good enough images for projection systems.  I saw one in Hinkle's  (OMC  ret. ) basement in Pasadena.  He used it on "hundreds" of  Bushnells in 1950's or '60's  subcontract work.  He got tired of the Navy collimators when at the U.S. shipyard in Boston.  Do not know if he ever used the Mk. 13. which has limited aperture anyway.

--Gordon Rayner

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