Telescope Reviews: Objective lock-ring collimation

edz - Just read a lot of the sticky posts on binoculars at the head of this forum and was amazed at statement(s) that most binos have no way of adjusting the objective lenses for proper collimation.
I have owned four pairs of binos (all different manufactures) and each one had provisions for objective lens adjustment. I'm posting this info just in case this tip has not been posted before.
There is usually a rubber or plastic "guard" that screws onto the ends of each barrel to, I assume, protect the objective lenses when the binos are placed upright on a flat surface. On three of these binos, these "guard" coverings were removed by unscrewing them from the barrel body. Once removed, you can look at the inner edges of the objective lens holder. There, you will find a locking ring that's screwed down against the objective lens, holding it in place.
Each locking ring has two slots opposite each other, where a tool can be inserted to unscrew the ring. Great CARE must be taken so as not to scratch the lens while loosening the ring just enough to allow the lens to spin inside its housing. I carefully used a jeweler's screwdriver in each slot and gently tapped the angled screwdriver(s) so as to move the ring in a counter clockwise direction enough to unscrew it about 1/2 to 3/4 turns. Once done, the lens can be spun inside its housing for collimating (the lenses are concentric along their edges which allow for axial adjustment when spun in their holders).
To collimate each lens, I held the binos just below my eyes while I stared at the sky (a star) with infinity focus. Keeping this eye focus, I then placed the binos to my eyes and could detect the non-merging images, which your eyes try to converge by focusing in a different manner. Once the "infinity stare" is mastered, you can now spin each objective lense so as to converge the double star images. Sometimes both lenses had to be adjusted but usually only one needs to be adjusted. To spin the lens, I washed my finger tips with alcohol to remove any oils/acids and used my finger tips to spin the lenses while looking through the binos at a fairly bright star.
Once the objectives are adjusted properly, the locking rings can be re-tightened carefully to a "snugged-down" tightness to finish the collimation.
I never had to adjust the prism screws since the exit pupils were round in all the binos I collimated.
I found that this collimation method is quick, easy and though risking lense scratches, works very well. On one pair right from the store, one locking ring was loose while the others had to be collimated to some degree.
I hope this info helps those with a collimating problem and solves the mystery you have (?) regarding the adjustment of the objective lenses in most any brand binoculars (my Orion "Little Giant" 10x70s have these locking rings).
A well-collimated, Mr Q

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What goes around, comes around, eventually.

Meade DS-10(10" newt)
10x50, 10x70 binos

Edited by EdZ (05/27/08 01:21 PM)

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