Assuming that Swarovskii, Leica, Zeiss, Nikon don't make lenses for glasses what should the average glasses wearer take into consideration to ensure they get the most of their expensive binoculars.
Glass or polycarbonate - any difference in quality?
Are some manufacturers better than others?
Do extra thin lenses make a difference.
Is an anti-glare coating worth paying extra for?
Seems incredible that many of us will spend a fortune on binoculars and telescopes without considering the lenses nearest to our eyes.
Recommendations/suggestions appreciated?
Thanks
Ian
[QUOTE=ikw101]Assuming that Swarovskii, Leica, Zeiss, Nikon don't make lenses for glasses what should the average glasses wearer take into consideration to ensure they get the most of their expensive binoculars.
Glass or polycarbonate - any difference in quality?
Are some manufacturers better than others?
Do extra thin lenses make a difference.
Is an anti-glare coating worth paying extra for?
Seems incredible that many of us will spend a fortune on binoculars and telescopes without considering the lenses nearest to our eyes.
Recommendations/suggestions appreciated?
Thanks
Ian[/QUOTE]
Glass is thicker and heavier. I love glass, but it's no longer practical.
A thin lens increases effective eye relief.
Anti-reflection (AR) coating is the MOST important thing you can do for a synthetic lens. I wouldn't buy a clear eyeglass without it! AR does not have the same dramatic effect on sunglasses.
If your prescription is rather stable and you learn how to clean them, AR coated lenses can last a few years and endure daily cleanings without a scratch!
John
Zeiss and Nikon do make glasses lenses and coatings. Mine are Zeiss, but I wouldn't actually have known if I hadn't asked my optical dispensery where the lenses came from.
My prescription isn't very strong so I use glass lenses. They are a bit heavier than polycarbonate or other plastic lens types, but the BIG advantage for me is their FAR superior scratch resistance--nice if you're constantly bonking your glasses into unrubberized camera viewfinders and microscope eyepieces, or if you clean your glasses under less than ideal field conditions a lot.
I don't have any practical experience with it, but I have heard from multiple sources that high-index plastic lenses (used to make thin lenses), and polycarbonate lenses even more so, are prone to significant chromatic abberation in comparison to regular plastic lenses.
Yes, get anti glare coating--it's important. One thing I've noticed though, is that on glass lenses the antireflective coating can make it harder to remove oil residues (more than nullifying their advantage until the lens is properly cleaned!). Zeiss and others have new generation coatings now that are supposed to repel oil and thus be easier to clean than past coatings.
To me, the most important consideration is the design of the frame. I like to have lots of peripheral vision, so I am inclined toward aviator style frames/lenses. I also like the lenses to be as close to my eye as possible (so I can use binos with as little as 14 mm eye-relief), so my glasses are a slightly modified design that fits closer than the standard aviator (doesn't come quite as low above the cheek and doesn't come up as high over the eyebrow which has the added advantage of transferring less grease from my eyebrow to the glasses lenses). I also like a very sturdy frame so that when I press my binos into my glasses they don't go all wonky and all the optics remain aligned. Finally, I like my frames to be made of quality metal that is fatigue resistant to the extent that they could be bent back into shape in the field without breaking should they be crushed. I like the frames to hold the lenses in by encircling them with metal and held tight with standard glasses screws (to which I apply Loc-tite so they don't loosen).
I've been using the same frames since about 1996 (wow-hard to believe!) with only a few incidents--all of which could be fixed in the field--but I've seen lots of other folks have any number of problems that were incapacitating. Examples include broken nylon loops that hold in the lenses, loss of screws that hold rimless frames to the lenses (screws that are not standard and thus harder to replace), super thin titanium frames that bend into strange shapes spontaneously in extremely cold weather, metal frames that snapped in half because the sides are held together by a single wire bridge over the nose that flexes slightly until it breaks from fatigue (I've seen titanium frames break like this), and cheap metal frames that break rather than bend when crushed (or when the wearer tries to bend them back into shape).
--AP