Servicing a Carl Zeiss Jena Sonnar 1:2 f=5cm T "v3b ZE CR arrs" for Contax

[mhw]

I got my hands on a fair condition CZJ Sonnar 1:2 f=5cm T lens for Contax rangefinders. According to the Sonnar 50mm f/2 overview it is a 1947 aluminum version. In addition to lots of micro scratches, there was mild haze and the aperture ring had a fair amount of drag. Inspired by this forum, I decided to service it. The lens mechanics work beautifully after servicing and the haze is much improved.

This lens turned out to be very different internally from the later Sonnars as documented by all Sonnar repair guides I found including Mike Elek's, so I wrote up a fresh iFixit guide. Enjoy! Any feedback is appreciated 🙂

Cleaning & lubricating a Carl Zeiss Jena Sonnar 1:2 f=5cm T (Contax mount, aluminum)

This guide is for a full overhaul of a 1947 Carl Zeiss Jena Sonnar 1:2 f=5cm T lens made for Contax rangefinders. The lens has an aluminum barrel...

www.ifixit.com

 

[GeorgeRazmadze]

Hello. What is the safest and best solution to cleaning the zeiss opton coated lens from haze and fungus? without demagong the coating? Thank you for your time.

 

[Sonnar Brian]

I use an eye-glass lens cleaner that is a mixture of alcohol and ammonia. I then place under a UV light.

@GeorgeRazmadze

 

[GeorgeRazmadze]

I use an eye-glass lens cleaner that is a mixture of alcohol and ammonia. I then place under a UV light.

@GeorgeRazmadze

Thanks. What brand was it? Wasn’t ammomia too harsh for coating? I researched that this zeiss cleaners is good and safe solution.

 

[Sonnar Brian]

I do not use the pre-moistened wipes on my lenses, only on my glasses.
See if the Zeiss lens cleaner is available in a bottle.

 

[boojum]

I do not use the pre-moistened wipes on my lenses, only on my glasses.
See if the Zeiss lens cleaner is available in a bottle.

OK, I am piqued. If used from a bottle as a liquid how is it manipulated that is better than the wipes? How do you do it?

Signed "Curious on the Columbia."

 

[GeorgeRazmadze]

I do not use the pre-moistened wipes on my lenses, only on my glasses.
See if the Zeiss lens cleaner is available in a bottle.

Do you mean this? I found this one. Thank you for your time.

 

[Sonnar Brian]

That looks good to me-

@GeorgeRazmadze

 

[GeorgeRazmadze]

I do not use the pre-moistened wipes on my lenses, only on my glasses.
See if the Zeiss lens cleaner is available in a bottle.

Was it self

I use an eye-glass lens cleaner that is a mixture of alcohol and ammonia. I then place under a UV light.

@GeorgeRazmadze

Was it self mixture or some kind of branded kit? What was the percent of ammonia? Thank you for your time.

 

[mhw]

I tried the Zeiss cleaning wipes on some lenses and they left residue.

For now I have settled on kimwipes + pancro lens cleaner. So far I haven't noticed any scratches left by this combination across my lens collection. I never use kimwipes dry or reuse them, and I always blow dust away with a rocket air blaster before wiping.