Are 1960s & 70s glasses worth the money?
I need a spare 7x35/8x40 for general countryside use (conservation work).
I've seen a Nippon Kogaku 7x35 (7.3deg) and a Bausch & Lomb Zephyr 7x35 (poss. military) at rather attractive prices (<£100 GBP). Both are in excellent condition; however, there's a possibility that either may need cleaning, and this would add around £40.
In addition, I own a pair of quite light-weight Pentax 7x35 CF porros that are pretty good and very 'handy', but they ideally need cleaning - they cost me half a days' wages in 1976.
Two key questions are:
For collectors I'd say they're probably worth the money.
But for day to day use you can find better bins for this sort of money. Things really have moved on a lot: in design especially EP design and in coating technology.
The problem though is finding better 7x35 bins which I still think might be close to the ideal combination. Though with today's wide EP designs the 8x40s give them a run for their money: one reason for 7x was wider field though slightly reduce shaking (along with slightly reduced acuity was part of the trade off).
But if you want to spend £100 to £150 on a bin a well chosen new bin (probably a porro) would be your best bet.
For example, the not yet shipped Vortex Raptor 6.5x32 ($110 so expect £110) are light, waterproof and will (probably) beat these old bins optically too. There are plenty of other examples to choose in addition to the Nikons you mention: the heavy Bushnell Legend 8x42 porros, Hawke Black Watch (I think) porros that go for £90, Leupold Yosemite 6x30 and 8x30 (not so easy to get in the UK). And there are others too. I'm sure Opticron have a competitor here too (SGA? HR WP is rather more pricey).
The only possible exceptions to this rule would be "alpha" porros of the last half of the 20th century. But you aren't going to find them for £100 to £150.
I pretty much agree with Kevin on this one. For example, there are quite a few Bausch & Lomb Zephyr binoculars on #bay auctions. Sometimes they are pristine and often they will need cleaning. The Zephyr is a good example of a classic older binocular which is competitive optically. But their value is toward the collector or to somebody who wants a backup to their older original instrument.
But if you are just looking for a spare glass, just get a decent new one in your price range. There will be at least some warranty and service.
Another good one to consider for a spare binocular is the Swift Aerolite. in 7x35 you get a 500' fov and in the heavier 8x40 it is 472. Neither have any waterproofing, but should work. Another option is just get another Nikon 7x35, since you know what you will get.