Praktica*ist, thank you on your comments. I wasn't particularly happy with the orientation too since I cut swan's reflection, but considering I had to chase a bird at f1.2 by focusing manually it's ok...
I paid 200 euros for this lens. Yes, it is expensive but lenses are rather expensive these days, especially new lenses. Ok, some vintage manual lenses are not that expensive but the price of collection quickly builds up, 50 euros by 50 euros and suddenly you're at 500. There are some more expensive old lenses too. So, this one is in the middle. Also, some new manual lenses for K-mount from Samyang, for example, are more expensive than this one. Samyang 85mm f1.4 is considered a cheap lens and it is 270 USD, the best price on internet. Pentax K 50mm f1.2 can be bought between 200 and 300 USD in very good condition from Japan on eBay. I bought mine locally from a photographer who used it extensively. It's rather dusty inside, but I didn't hesitate too much, around a day and a half because it was a good offer considering no shipping involved and I could try the lens too. If you read reviews here on the site, they will see that it is difficult to focus, that it is not sharp, full of aberrations at f1.2. I think that those reviewers didn't know how to use it and how to focus and what to expect. This lens is sharp at f1.2. It is sharper and without aberrations compared to AF version of FA 50mm f1.4 which I also have and bought it new. This manual lens is two times heavier too, better glass, more metal. Please check some of the photos in recent posts, I took them all at f1.2. Perhaps I should write review too. This lens is amazing actually. At night it is like at home. This is night, indoor lens. But good for very dark sunsets. Light is beautiful then too. This lens requires very little post processing. For delicate shots I focus in Live View. Focus peaking is your good friend. My keeper rate is very, very high. It can achieve focus even in optical viewfinder if you set the focus micro-adjustment well, I set mine to -10, but it is a gamble and would't really recommend it unless you have less important static subjects. I use it on K-1, didn't try it on my other camera, K-5 II. I have this lens for exactly 3 weeks and so far it doesn't leave my camera. At f2.8 it is ridiculously sharp. Do you need this lens? Well, only you can tell. Do you want it, that is another thing. If you want part of the Pentax's history on your camera then the answer is simple. It is first Pentax lens with f1.2 and together with A version of this lens the fastest Pentax lens ever. All K glass which was made before they started to introduce cost cutting is amazing according to the users on this site. You will not make a mistake if you buy it cause these things can be resold, they don't lose value like consumer electronics. This is classic, well know equipment. But be cautious to get a good copy without fungus, hazing or separation because this lens is very hard to open and service for less experienced people.
Good luck.