Crackling shots?!

Ferrania film was always a bit grainy and any ISO 800 stock even more so. Given its 12 years OOD now guess you can't complain too much and it doesn't detract!
Was it scanned off the negative or a print? It looks like printer banding.

So do I, thanks for sharing. That lens seems to have been a good find.

If the pin isn't causing a problem perhaps it doesn't matter with that one. Some pins protrude more than others. If you can remove it easily then probably best.
Any images from it you can share?

Yes it is. That lens isn't the same as Pentax A as it doesn't have the Pentax version electrical contacts. The P setting is a dedicated Program function for the XR-P. Otherwise it will work as a manual Pentax K / M lens.
Read the XR-P camera manual here for an explanation: https://www.butkus.org/chinon/ricoh/xr-psingle/ricoh.htm
(Guess OK to link to Ricoh things from here nowadays!)
As stub has the lens, what happens when set to P? Does it set auto settings? I suspect it can't on a Pentax, even if it is a Ricoh built one!

My suggestions FWIW:

I'd say it's his K02 http://photografica.robinparmar.com/vivitar28detail.html#K02

By the P/K. The R is for Ricoh and it does have the pin on that lens. Fortunately it was not protruding enough to get stuck on your camera body. Potentially it could though.
See here.

Well yes, it would work on both. From your photo it would appear there is that Ricoh pin.



It's for when it's used on Rocoh's XR-P camera which had several modes of programmed autoexposure, when used with P lenses. http://camera-wiki.org/wiki/Ricoh_XR-P

As you can see, yes & no ! Definitely not a Pentax lens per se, it's a Vivitar lens designed to fit Pentax & Ricoh K mount cameras in 1984, in particular the Ricoh XR-P.

In my K-1 I now use 128Gb cards and write both jpeg & raw to both cards. That normally does me for over 1200 shots and surely safer than moving them over to a single portable drive which must be at more risk of failing than two SD cards?
Carry some spare SD cards and you'll be good for plenty of shots without worrying about backing up while you're away! Well you will have backed up the images as you take them.

Some well seen shots there, great stuff!

I notice Am azon have taken a whole 99p off the list price of the new 50. Wow! In fact they've put it up from around £1060 last week. So much for special BF deals.
PS If readers aren't aware SRS's deal is marginally better by around £300 !

I'm sure you can still find a use for it if you keep it. Is it FF modified by removing the baffle?