Pentax Spotmatic SP

My Notes:
This was another camera from Trevor but this time it wasn't one that he was selling on his table.  This time he had purposefully set this one aside for me as it was a camera that I "must have" in my collection.  It was the same type of camera that he started his photography career with back in the day.  To give you an idea of how new I am to all this, I'm ashamed to say I didn't really know about this iconic camera.  I currently use it with a Super-Takumar 1.8/55 and with some ISO adjustment I have a usable light meter with a modern battery (once I read the manual and found out how to turn it on).  This is such a lovely camera to use, the focusing is a dream and I was pleased with the results, although need to practice more.  I do get the odd black diagonal mark across one corner that I can't work out why so any ideas let me know.

Camera Details
Manufacturer: Asahi Pentax
Model: Spotmatic SP
Year of Manufacture: 1964
Lens: Interchangeable M42 mount
Country: Japan

Camera Links:
Camerapedia Page

Manual page by Butkus