Cascadilla
Well-known
I recently bought a 5 cm f/3.5 black and nickel collapsible Tessar for Contax and would like to get a protective UV filter for it. I'm not sure if it is threaded but it is definitely smaller than the 25.5 mm filter that fits my later collapsible chrome 5 cm f/2.8 Tessar. Any thoughts about what might fit?
Rayt
Nonplayer Character
It might be a push on filter.
Cascadilla
Well-known
Thanks for the suggestion. 42 mm push on filters would work--the standard 42 mm lens caps fit. But I am hoping for a filter that screws in to the inner mount so that it will be easy to set f/stops.
milescl
Well-known
25.5mm screw-in, 27mm push on, or 42mm push on.
Cascadilla
Well-known
25.5 doesn't fit. I have several filters that size and they are too large to screw in. This is an early lens so I guess a non standard size isn't a huge surprise, but I hope I can find something that will screw in.
wlewisiii
Just another hotel clerk
I don't know but I wish I had the problem to figure out? Looks like a beautiful lens, but then I'm a sucker for the Tessar style lenses. My goal is to get a good prewar un-coated CZJ 50/3.5 adjusted as necessary for my Nikon S2 
Bill Jones
Contax Lens User
Only the 27mm and 42mm slip-on filters were catalogued in the US prior to the war. None of the Contax lenses used screw-in filters prior to the Contaflex/Contax II era. Filters for the Tessar 5cm lenses were prior to the war were always catalogued as push on style.
Bill
Cascadilla
Well-known
Thanks for your reply--I do own a 5 cm f/2 black and nickel Sonnar that does have 40.5 mm threads and a chrome collapsible 5 cm f/2.8 Tessar that does have 25.5 mm threads. I'm not certain that even if I found a 27 mm push on UV filter that it would fit the black and nickel Tessar that I have since the 25.5 filter is too big to fit it and I think that the outside diameter of the threaded portion seems a bit smaller than the 2.8 lens. I did find a 24 mm UV filter on eBay so I may give that a try.
Bill Jones
Contax Lens User
You have a very nice looking Tessar there. Like you I would have expected it to have 27mm slip on and 25.5mm screw filter sizes. They were the standard ones for the Zeiss Jena 5cm Tessars. Is it possible that your filter 25.5mm thread has paint or dirt or a small ding in it. Look next to the spanner slot above the word "Carl".
As an aside, one never used a protective UV filter back in the day, a light yellow maybe, since they would add 2 more reflective surfaces in the days before coating.
Bill
Malcolm M
Well-known
The Contax Way (1953 edition) mentions nothing smaller than 25.5mm. Are you sure it's a screw thread? Try tracking the grooves anticlockwise with a sharp point. If it comes out, it's a thread. If it keeps going round and round, it's machined circles. Another possibility is 22mm, as used on the Kodak Retina
.
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dexdog
Mentor
I have a 5cm f3.5 tessar with 138 series serial number, it does not have a threads next to the lens, but has machined circles as noted by Malcolm M
Cascadilla
Well-known
The threads look clean to me and don't appear damaged in any way. I take your point about UV filters not being in common use when this lens was made, but as I'm not sure how soft the glass was for this front element I'm inclined to be cautious. There are too many Leica Summars and collapsible Zeiss Sonnar around that produce soft images due to damaged front elements.
Cascadilla
Well-known
Thanks to everyone who replied--I have a 24 mm UV filter coming next week from eBay so I will find out if that works.
rulnacco
Well-known
If that doesn't work, find someone who's got a digital caliper and have them measure the diameter it for you. It would at least help eliminate the guesswork.
I found the same problem with my 5cm F3.5- did not take the 25.5mm filters that the F2.8 lens takes. I think the threads were not originally intended for Filters, but were for the retaining ring- and happened to get filters made to the same 25.5mm spec. If you get a filter that is close- wrap a little teflon tape around it to keep it in.
Other "bizarre" thread size: the post-war 5.8cm f2 Biotar takes 40.5mm threads, a standard for Zeiss. The 1936 pre-war Biotar 5cm F2- uses the same push-on caps and push-on hoods, but cannot take a 40.5mm screw-in filter. It takes 40mm filters, I use a Canon 40mm to S-VI adapter with it.
Other "bizarre" thread size: the post-war 5.8cm f2 Biotar takes 40.5mm threads, a standard for Zeiss. The 1936 pre-war Biotar 5cm F2- uses the same push-on caps and push-on hoods, but cannot take a 40.5mm screw-in filter. It takes 40mm filters, I use a Canon 40mm to S-VI adapter with it.
dexdog
Mentor
I am a fan of teflon tape. Really useful for fitting filters and lens hoods to the kinda oddball lenses that I collect and use.
Cascadilla
Well-known
Thanks for the teflon tape suggestion--when I get my 24 mm filter I will give that a try if it doesn't fit.
Cascadilla
Well-known
The 24 mm filter arrived yesterday and with some finagling it will stay attached to the Tessar. For what it's worth, it is a Heliopan skylight filter if someone else has a similar problem. 