Binastro,
Thanks for your evaluation. With the scarcity of users, and so opinions, of the Zeiss 20x60S this is much appreciated.
James,
I concur with binastro that there could be 20x60 binoculars around with better optical performance than the Zeiss (but you'll need a tripod for these and so you're back on scope ground). The implication here is that there's room for improvement in the Zeiss and yes, that's true. I think that a second generation 20x60S would be considerably improved with the latest Schott glass as applied in the HT range of binoculars, as well as with coatings like those used in the FL range. Also, the eye-ocular interface with its Dialyt-type hard eyecups is uncomfortable, old-fashioned and yes, seriously obsolete.
That said however, it's still a miracle to me that I have been using the big Zeiss for so long without complaints. Note that the 20x60 is always used alongside state of the art 8x40 or 8x56 binoculars with considerable better light transmission. The 20x60 is by nature far dimmer than these low power, large exit pupil instruments, but I can't remember being seriously disappointed by that. I think it tells something about its resolution.
Another flaw is its susceptibility to lateral CA. One should be prepared to carefully keep the object in the center of the viewing circle to bring the best out of the instrument. Which brings me to a crucial factor involved in the use of the 20x60S in general: experience. This is definitely no point&shoot, grab&go binocular. The instrument has a character of its own, and so you'll have to learn to adjust to its idiosyncrasies. But why not, the reward is considerable.
With respect to price and costs of servicing, yes, this is necessarily a very expensive instrument. However there's a good second hand market where you'll pay 50% of the retail price, round about 2500 Euro or 3000 USD. Servicing is expensive as well because Zeiss will strip the instrument completely to make sure the stabilizing mechanism is behaving to perfection. If I'm not mistaken Zeiss asks 1500 Euro for it.
So there's the question of durability. How sturdy is the big Zeiss? Well, all I can say is that I'm surprised. My instrument is still in the same condition, optically and mechanically, as it was when I bought it. I'd say it's a well constructed optical instrument.
Renze