Converto-Sigma 135mm/3.5 (Exakta)

[frogbog]

I found this weird "little" lens for sale today. It has a low serial number (72xx), and comes with the matching 2x converter and an original Sigma softcase. I assume it is quite rare, but is it worth anything, or is it any good? Any information would be appreciated. The seller is asking £90, which I find rather steep for a lens I don't know (or can find) anything about.

[luisalegria]

Very very early Sigma and quite uncommon.
I have seen this once before.
A similar lens without the matched TC was sold by Sears in the 1960's in their brand.
A collectors item for sure.

Problem is, with these odd, rare, but unpopular things, the market value isn't high.
And the volume is low so there isn't much experience from which to derive a price.

[frogbog]

Thanks for the info! You confirmed my "suspicions"... The seller just sent me some (really poor) photos of the front and back; the serial number had 5 digits, and the mount turns out to be Exakta. The barrel of the lens looks really good, but from what I can see from the new pictures, the aperture blades are misaligned, the front element is hazy and the insides are dirty. I asked him if the price was negotiable, but of course it wasn't. So I'll leave it be!

[cropshy]

I've got this lens under the Bower brand name and it looks brand new. I don't have the teleconverter. It's got a t-mount type thread, but with my t-mount it doesn't focus to infinity. I paid maybe $25 for it on Ebay last year. I haven't really used it much, but I recall it performed like other old, slowish 135mm lenses I have.

[casualcollector]

The Sears version, with its 35mm sibling.

[cropshy]

I've got that Sears one as well. Oddly, the Sears lens focuses to infinity with my t-mount on my Nikon.