Pentax-F is the series, they're K mount and will work on your K-x just like the 18-55mm does.

A quick runthrough of the Pentax lens "series"

SMC Pentax (sometimes called K series) - manual focus, manual aperture, the original 1975-77 range which were superbly made

SMC Pentax-M (M series) - functions same as the K series but smaller and lighter. More commonly available as they were made for longer

SMC Pentax-A - still manual focus but now has an "A" position on the aperture for use with suitable bodies, if used with your K-x these will work like a current lens but with manual focus only

SMC Pentax-F - the first standard Pentax AF lenses, work just like the current ones when aperture is set to "A"

SMC Pentax-FA/FA-J - same functionality, FA-J lenses lack an aperture ring which isn't a problem with the K-x

SMC Pentax-DA/DA-L - the current lenses like your 18-55mm

Try to stick to Pentax-F or later for now, earlier lenses will fit and work but with limitations (you have to use stop-down metering with anything earlier than the A series, and the A series themselves while able to work with all exposure modes are manual focus).

Sounds like the earlier one then, in which case well worth having it sorted out. If you want a vintage camera to go with it the SV is probably the most readily available for sensible money in working order, although the Super Takumar lenses were on the market by the time the SV arrived.

The best site for screw mount gear is probably this one. It has dates of production and some distinguishing features for most lenses, the only snag is it doesn't include photos (but does for most of the screw mount bodies).

Yes, it's well worth having it professionally cleaned. Image quality should be excellent and in any case it's not particularly common. You have a piece of history there - according to the AOHC site there were two versions made 1959-61 and then 1962-66. They list the later version as focusing closer (2.5m rather than 2.7m) and weighing 900g to the 750g of the earlier version.

The two rings are for preset aperture control. You use one to set the aperture you want to shoot at, then turn the other to stop down to said aperture. This allows you to focus with the lens at f3.5 then shut down instantly to the selected aperture without having to count clicks or look at the aperture control to see what you're selecting, as you would if the preset mechanism wasn't fitted.

I suspect they may be another one of the generic brands which did the rounds in the '80s. If you want a good budget lens then save your money and try to get hold of one of the better Pentax autofocus zooms in that focal range - try the Pentax-F 70-210mm, Pentax-F 80-200mm, or the current DA 50-200mm.

Stupidly cheap generic lenses can be fun, but I'm guessing you're starting from scratch and trying to build a kit, in which case you really want a lens you can rely on rather than something that's fun to fiddle around with.

I doubt they'd really mind providing the tyres meet the relevant regulations, which are, after all, supposed to ensure that they meet a minimum standard to be safe for road use. You're more likely to have handling trouble with cheapies from your local garage chain than you are with the specific brand you've hunted down because you read they're the best fit for your car.

I want Kumho KL71s next time, slightly larger but will fit without modifying anything and won't throw the speedo out. Apparently they counter the fact that it reads low, so you end up with an indicated 60mph being a genuine 60 rather than 56-57!

The exposure looks fine to me, what I have found is that the GIMP can do wonders if you feel it's slightly underexposed. Just use the brightness and contrast controls to darken the images and raise the contrast to taste. Best of all, it's free software.

ISO 400 should be plenty in daylight even at this time of year - I use it all the time and shutter speeds at f8 or so are fine for hand held shooting.

Street photography seems to be the hardest to get right. You're reliant on everything coming together just so and you won't have time to fiddle with settings.

Weirdly if I do take a camera out in an urban area I find myself pointing it at first floor level or above. In many places the ground floor of shops has been mangled beyond recognition to suit modern retail chain corporate image, but if you look higher up (as hardly anyone else does) you see that originally these were all part of the same building, or that you can make out the cast lettering of the original owner, or similar. Hereford is particularly good for this - there's even a Tudor shop which was simply lifted up and placed on top of a 1960s built ground floor when the town centre was redeveloped then, much like you or I would put a book on a shelf!

I have a couple of moon shots on my current roll of HP5, not sure how they'll come out as they were taken with the SV and my longest screw mount lens is 135mm.

I regularly use B mode, a cable release and my watch to time exposures longer than a second (the longest the mechanical bodies will offer). Generally I meter at the widest aperture and then calculate the correct exposure at the one I want to use accordingly.

At that price I'd be more inclined to buy an old film body and a lockable cable release for your ultra-long exposure needs!

The rubber compounds are softer in true winter tyres, but I can't say I had any trouble. I'm waiting for tyre manufacturers to notice Geckos and attempt to copy their feet, as it'd have very interesting effects for rockcrawling!