Hi people,
I've nothing else to do right now than to flee from the humid 33.3 centigrade temperature outside, so I would like to make a note on an ergonomic issue that I've found out about just now.
I wear specs, and to use my Pentax Papilio's 6.5x21 properly, I twist the eycups all the way in, to gain the maximum FOV. Somehow this didn't seem right, I felt I had to "work" a little to get a relaxed view. Then I began experimenting, setting the diopter slightly off in the minus, to - 0.5. This was better, but I still had to do some eyework. I then began to experiment by twisting out the eyecups slightly, and independly, and to my surprise, I found a setting that, combined with the slightly-offset diopter, caused no more eyestrain in the image. I think the Pentax is well aligned, from what I can tell, so the issue has to be in my eyes/specs combination. I went to check, and found my specs to be sitting on my face slightly asymmetrical. The right glass is ever so slightly closer to my face than my left glass. I don't notice this at all when wearing my specs, I've got good vision and feel like the specs are sitting comfortably on my nose.
By twisting out the right eyecup slightly, I seem to have managed to get a symmetrical position of my bins against my specs. The image now is flawless and relaxed.
Maybe this phenomenon has been discussed before on BF, but in case it hasn't, I thought it important to tell all people who wear specs to experiment with uneven twisted eyecups if they feel the view isn't just "right" with both eyecups neatly twisted all the way down. There may be some point in doing so, it could be that the obvious thing to do is to twist the eyecups up or down in the same manner, evenly, and that no-one has thought of differences in facial structure, resulting in spectacles that are not sitting symmetrically.
If there has been a thread on this issue before, I do apologise. Anyway, I found it too important not to mention, could easily be overlooked.
Best regards,
Ronald
In general, spectacles should be fitted to have the same eye relief on both sides.
Rarely, with certain types of asymmetric facial features, exceptions from this rule have to be made. Even more scarcely, the wearer needs to have the spectacles asymmetrically adjusted for purely optical reasons.
But if the specs have gone out of adjustment, the wearer may slowly adapt to the changed optical effects.
Sometimes this can be like a curse, when the old specs are replaced with new ones - the brain has adapted to the different image perceived through the old specs and has a hard time to adapt back to normal again.
Even without spectacles, the eyecups may need to be asymmetrically adjusted. In fact, I found out this just recently. My right eye seems to be deeper from the eyebrow than my left, so I pull out the left cup about 1½ mm to synchronize the FOVs and avoid kidney-beaning from the left barrel.
//L
Ronald:
A good optician, and that is the guy that fits your glasses, should be able to adjust your
eyeglasses to fit your face, then using your binoculars will be a simple adjustment, with
equal eyerelief.
.
I remember as a child, my glasses could be bent out of shape, and so that may be a good
place to start.
Jerry