[StrixNebulosa]

I have a recollection that a few months ago a Zeiss thread contributor mentioned that he had sent his old Dialyts to Zeiss repair for a tune-up and that they came back with upgraded glass and other enhancements. I have a pair of 10x40s that I bought circa 1971 and used until I upgraded to FLs last year. Having them "modernized" appeals to me. If someone who knows the location of that posting could send me a link to it, I'd be grateful.

Strix

[mak]

Originally Posted by StrixNebulosa

I have a recollection that a few months ago a Zeiss thread contributor mentioned that he had sent his old Dialyts to Zeiss repair for a tune-up and that they came back with upgraded glass and other enhancements. I have a pair of 10x40s that I bought circa 1971 and used until I upgraded to FLs last year. Having them "modernized" appeals to me. If someone who knows the location of that posting could send me a link to it, I'd be grateful.
Strix

I think the thread mentioned the upgrading of phase coated roof prisms (Schmidt - Pechan) into pre -phase coated Dialyts (1988) & at a cost, not putting in FL glass or similar.

[David Dombrowicz]

I own 8X56 BGAT Dialyt from 1986. I thought that it was technically impossible, short of a total replacement of the whole optical system, to upgrade the binoculars with addition of Phase coating.
Did someone ever learnt something about such an upgrade.

Thanks for any information on the topic.

David

[henry link]

The thread with a post about changing the prisms in an old Dialyt is here:

http://www.birdforum.net/showthread.php?t=115605

A Dialyt from 1971 would also lack T* multi-coating, so just installing a P* coated prism cluster wouldn't bring it up to the performance of the post 1988 phase coated Dialyts. Even so, if the service is free it would certainly be worth doing for the phase coating and because there is probably some tarnishing of the silver prism coating in an unsealed 37 year old binocular.

[brocknroller]

Originally Posted by henry link

The thread with a post about changing the prisms in an old Dialyt is here:

http://www.birdforum.net/showthread.php?t=115605

A Dialyt from 1971 would also lack T* multi-coating, so just installing a P* coated prism cluster wouldn't bring it up to the performance of the post 1988 phase coated Dialyts. Even so, if the service is free it would certainly be worth doing for the phase coating and because there is probably some tarnishing of the silver prism coating in an unsealed 37 year old binocular.

Hi Henry,

Awhile back, I posted a thread about the possibility of upgrading my old single-coated porros with the latest multi-coatings.

I was told that it couldn't be done despite that fact that it only changes the thickness of the lens by hundredths of an inch, because the lenses had been configured for single coatings so the lens configuration would need to be changed to accommodate the new multi-coatings.

Do you agree with this?

There are many excellent old porros that would as good as if not better than top roofs costing thousands of dollars more if only they could be updated with newer coatings.

Couldn't something be done to compensate for this small difference in lens thickness, for example, changing the focal length of the binoculars?

I was also told that it's not only the coatings that are better today, but also the glass. And that it's the match of coatings and glass that make today's top roofs superior.

Please comment on this also. Thanks.

Brock

P.S. I sent you a PM on CN earlier in the week. CN has been down for upgrades so I have not been able to access my PMs.

[henry link]

Brock,

I don't know much about the technical issues, but I'm pretty confident this scheme will founder on cost alone. If you can find anyone to do such custom work the cost will probably exceed the total prices of several high end binoculars put together. I'm sure you'd have to pay upfront with no guarantee of a good result and there's the risk of one of these old lenses cracking in the coating process.

FWIW the thickness problem sounds dubious to me, but it's true that the refractive index of coating material should be matched to particular glass types. The ideal coating would have a refractive index half way between air and the glass type being coated, so different materials or combinations of materials are needed for each glass type in a binocular for the best results. Inexpensive binoculars get by pretty well without matching.

I haven't been able to log on at CN lately and I need to clear out my message box here. Don't you have my e-mail address?

Henry