Looks like the real thing Janet
You can't see any sign of a clip and I held a M42 lens with the cap attached in front of my screen and the proportions seem right, so what you've got is very, very rare
If I were you I'd sell it and buy the Jupiter version It's worth as much as someone want's to pay for it. To a Contax collecter who didn't even know it existed the sky's the limit.
There's a rare Pentax M42 4,5/85mm Ultra-Achromat-Takumar on ebay for £2,500 and it isn't really much use to anyone other than a collector at least your's can be used In fact it might be worth sending a few pics to that dealer, because he's in Germany and see if he's interested and can give you an idea of the value.
Edit: Although on 2nd thoughts he will probably try to rip you off!
Good Luck with it whatever you do.
shimbo
You can't see any sign of a clip and I held a M42 lens with the cap attached in front of my screen and the proportions seem right, so what you've got is very, very rare
If I were you I'd sell it and buy the Jupiter version It's worth as much as someone want's to pay for it. To a Contax collecter who didn't even know it existed the sky's the limit.
There's a rare Pentax M42 4,5/85mm Ultra-Achromat-Takumar on ebay for £2,500 and it isn't really much use to anyone other than a collector at least your's can be used In fact it might be worth sending a few pics to that dealer, because he's in Germany and see if he's interested and can give you an idea of the value.
Edit: Although on 2nd thoughts he will probably try to rip you off!
Good Luck with it whatever you do.
shimbo