While to certain extent that�s true, there are certain basic realities about optics and hence binoculars. But here there�s another factor: Fifteen years ago I published a book on hunting optics. It�s out-of-date by now, the reason I�m just finishing up another, but at the time many people considered it among best books on the subject. Consequently, many people ask my opinion on hunting optics, and don�t expect: �It�s all personal preference based on hunting and glassing style, so there�s no answer.�
That�s one of the reasons Rick has long encouraged my presence here, and part of the reason I can provide at least some suggestions is for decades I�ve watched other people use binoculars, and normally test binoculars with at least one or two other people, so I can see if they have any problems. Conseqtently, my suggestions aren�t just based on my �personal preference,� but on the experiences of many people.
On the other hand my friend Kirk (Shrapnel) has had no one to please but himself. Consequently, when he firmly states he�s found 8x a lot better during his decades of using a lot of binoculars, he�s saying that about himself, which is indeed �personal preference.�
Other people here also prefer 8x over 10x, and there are reasons for that, incuding hand-shake. Some people also do most of their glassing offhand, and some do it from the cab of their pickup with the engine running. Also, 8x42�s provide a larger exit pupil than 10x42�s (though 8x32�s do not) and that can be a factor in glassing comfort as well.
But the other reality is that 10x does provide 25% more detail than 8x, everything else being equal. And I have yet to run into anybody who didn�t see something better when they looking through a 10x versus an 8x of equal quality. That has been universal over decades of testing binoculars with other people, regardless of their color perception or most other individual factors.
One individual eye-factor that can make a major difference is interpupillary distance. On average women have eyes closer together than men, mostly because women are on average smaller, but there�s considerable overlap. One of the surprises I had years ago was when a guy I know asked about a good 8x30 or 8x32 binocular for his woods hunting. At the time one of the best was made by Nikon, so I recommended it. He bought one and couldn�t use it, because despite his fairly broad face his eyes were slightly too close together for the Nikon�s minimum interpupillary distance. He could see OK at first, but after a minute or two started feeling eyestrain.
Just this morning I was testing three 10x42�s with the help of my wife Eileen, who has also looked through a lot of binoculars over the years, partly because she wrote the optics column for the NRA magazine Women�s Outlook. She has an interpupillary distance on the low side, and had trouble with one of the 10x42�s for the same reason.
On the other hand, when one of my sisters started bird-watching this year around her home in California, she asked about a good binocular. Since her birthday was coming up, I had her measure her interpupillary distance, then mailed her the same Nikon 8x32 my friend couldn�t use, since I still had one on hand. It works great for her, because her eyes are a wider-set than his�and Eileen�s.
All binoculars are adjustable for interpupillary distance, but some are more adjustable. I didn�t ask zeissman about it, partly because his user name says he�s a man, and partly because the Swarovski 8x32 EL�s interpupillary distance is very flexible.
If anybody prefers to believe there�s no possible answer to zeissman�s question, that�s their right. But I obviously don�t think that�s totally true, and neither do several of my friends who constantly test optics, both for hunting and bird-watching.
