Alexis Powell
Natural history enthusiast
Where is Bill Cook? This is the hour of his opportunity to explain alignment, collimation, conditional alignment... !!!!!
--AP
--AP
Reading the posts above regarding collimation makes me wonder if we are naming this problem correctly, it occurs again and again on this forum, so as usual, it's probably a misunderstanding of mine.
I have had several binoculars where one of the barrels had/has its sweet spot off-centre, but have been in perfect alignment. I understood this to be a collimation issue, as in telescopes which might require the collimation to be set up by the user. Is the misalignment of the barrels (with each other) simply part of the collimation setup, or is it a separate feature? (It's nice to have the correct terminology when returning binoculars).
For people who want to use them without glasses, they have too much ER and thus blackout issues, especially the 8x42.
......... I really wanted to like the NVs but the above issues were deal breakers for me.
Now I am wondering if it could just be a field stop causing what I see as barrel mis alignment since the view is so relaxing with no eye strain.
The field stops definitely could be vertically misaligned without causing miscollimation between the right and left telescopes. The Noctivid almost certainly uses eccentric rings at the eyepiece end for collimation. In most specimens of binoculars that use that method there will be at least a little vertical offset between the right and left field stops. Sometimes it can be large enough to be distracting, if a lot of eccentricity was needed to achieve collimation.
If your field stops are vertically offset by 1/8 of a full moon that would be about 1/16 of a degree of real field (3.75 minutes) or about 37.5 minutes of apparent field for a 10x binocular, not very much. If you look at a blank wall or sky and move your gaze down to the field stops at 6:00 you should see a little vertical offset between the two, if that's the explanation.
That much offset is common with eyepiece eccentric rings.
Robert, if you take a tape measure and measure the vertical offset and horizontal distance to the object, with some trigonometry you can calculate the discollimation in degrees or arcminutes. If you let us know the distances I can do it for you. Bill Cook has written about acceptable tolerances here: http://www.birdforum.net/showthread.php?t=294668&highlight=collimation+tolerance&page=2
260 feet distance and 8β offset