When it comes to binoculars being out of alignment, how much is too much?
http://www.birdwatching.com/optics/.../alignment.html
When I test my bins in the way that is described in this link I find that mine are just barely out of alignment. I have a cheaper pair that are totally out of whack, but the ones that I use and love are midrange priced and from a reputable seller. I'm sure they would correct it for me, but I'm not sure the postage and the time without them would be worth it. I've often wondered if the image could be a bit sharper with them. Is it possible that proper alignment would sharpen the image a bit?
Eyestrain with prolonged use, and headaches, can result from a binocular whose images can barely be aligned. Fortunately your binocular's adjustment isn't that bad, and required this test to reveal a definite misalignment. But, this test is crude, as the instruction admits, and if it shows an error, correcting that error would likely be noticeable.
The main difference to me between binoculars that are tolerable and spot on are speed in getting the view. It takes that extra second for the eyes to misalign themselves to unnaturally accommodate the binocular. And an extra second also, to realign themselves naturally, after removing the binocular from the eyes.
The criticality of the situation depends on the direction of the misalignment. The eyes naturally "cross" when looking at close objects, so a misalignment that requires crossing is quite benign. But for the eyes to diverge outward or vertically is completely unnatural, and just a little of that gets to be a problem real fast.
That's textbook, but what do you do? It would hurt to be binocularless for a couple of weeks if you use it every day, but not so bad if only once a week. On the other hand, it's a worse transgression against nature to use a misaligned binocular, the more frequently you do so!
So here's my totally arbitrary personal test. Focus the binocular on a distant (half mile or more) object, then remove it from the eyes and relax a bit. Gaze at the object with naked eye. This will allow the eyes to align themselves to parallel. Now, look at the object through the binocular. If it takes more than 1.0 second (Mississippi-ONE, spoken quickly, as by Nawthunuz, not as by the likes of me, actually hailing from that state, who take about 1.3 seconds) to nail the view, ship it and pine away, you'll be glad you did.
Ron
If you wear glasses, be cautious of trusting that test, as it may be your glasses that are out of alignment. I tested my binoculars a few years ago after suspecting misalignment, and was disappointed to find they were out quite a bit.
Then I remembered I'd had headaches since one of the kids head-butted me in the face, and thought to have a look at my glasses from the side. They were obviously twisted so the lenses weren't parallel to each other. I twisted them back, and the headaches and apparent binocular misalignment were gone!