This is another lesser known German manufactured lens from the 60's and 70's made for 35mm cameras. This lens I would say performs as well as a Leica R lens. This particular Schneider-Kreuznach has Universal Pentax screw mount. Here's a pic...15 aperture blades! That's unbelievable, and they all work together flawlessly even after all these years!
It looks a solid little lens, similar to the Pentax Ashi lenses, I have a M42, 135, F2.8 Rayette from Japan with 8 aperture blades all my other lenses have 5 or 6 blades. Now that I have seen a photo your lens I am starting to think that I would like to try one out.
It is a solid lens indeed, if you can find one I suggest you jump on it. I bought this one for $250 USD attached to a camera no less. The camera is an Edixa which no one ever heard of. I was called an idiot and many other wonderful names...lol...but I knew I wanted it. In my opinion, it was well worth the price of all the names they called me put together.
Schneider_Kreuznach is quite a well known brand and they are still producing. You can read more about them here: https://en.wikipedia.org/wiki/Schneider_Kreuznach. I have never used one of them but I have seen images made by them. That is a beautiful image of the flower that you have uploaded. Lots of fine detail there and you got a bargain with that lens. Keep the images coming.
I find that such people lack a lot of knowledge about photography and cameras in general and forget that it is the photographer and not the camera that take great pictures and Most of all they have done very little in their lives
For those interested, this is what the whole outfit looks like and all for $250 USD. Thanks for visiting.