SRS and Park Cameras are both advertising them for £639, I'm given to understand that RRP is about £1100?. If you look up "Pentax 50-135mm" on ebay you'll find the SRS sales listing (they had three left after I bought mine).

Well, I bought it from SRS via ebay so I get two years guarantee. I'd imagine it will fail within two years if it's going to fail!

I'm really not that worried about SDM. I know there were problems but I just don't seem to see as many complaints now as I used to. Pentax aren't daft, they know that warranty claims cost them twice (in the actual repairs and also in goodwill/PR). I strongly suspect they've upgraded the design. If it fails after those two years I've seen instructions for a DIY repair, which basically involved unscrewing the lens mount and twiddling the motor. The theory seemed to be that the motor can stick, thereby making the lens inoperable.

Further conjecture - I've now seen two places selling the 50-135mm for the price I paid, which is little more than half RRP. Are Pentax planning a replacement and selling off stock of the old lens?

Hmm, it does sound as though there won't be a trickle-down of cheap used K20D and K7 bodies for a while!

It isn't the bonk------bonk-----bonk-----bonk that bothers me so much as...

"Bonk"-UUUGHHHHH!
"Bonk"-AAAAHHHHHHHHH!

Some of them sound like an air bed from which someone has just pulled the plug!

Never mind, ordered my new 50-135mm, organised selling my Discovery and will be hunting Subaru Foresters from now on. Found a possible at a dealer in Birmingham which I might be able to go and investigate this weekend, if everything else lines up.

That old 109" should be a pretty safe family car. They generally come off better than whatever hits them, providing you have decent seatbelts fitted.

If you want a decent fisheye for sane money look at the Samyang 8mm, it has rave reviews in most quarters including from Photozone, who usually seem hard to please.

The adapter will be able to convince you whether you want a fisheye or not. Personally, I'm curious but not terribly keen. I just find it difficult to fill the frame with fisheye or ultrawide lenses, which always seem to need something stuffed in the foreground of the composition to make it work. Given I mostly go for either arty shots of isolated bits of structures (if the reaction is "What on earth is that?" then I'm happy - I'm trying to show the fine detail that most people miss) or carefully framed landscapes to lose the scruffy ground between me and the interesting part of the scene a fisheye wouldn't be much use to me.

I'd agree on 50mm being a little too long for a DSLR. Then again I'm finding I prefer 40mm or 35mm as a standard lens on film too!

The DA 35mm or the 21mm Ltd would be much handier as a walkabout lens than the 50mm.

Well, after a bit of thought I've ordered the 50-135mm.

My thoughts are that the 70-200mm would have been a big, bulky thing which would only have come out for times when I don't mind being obvious, which are few and far between. The 50-135mm is compact and unobtrusive by comparison, it also covers a similar field of view to that of my much-loved 120mm f2.8 on film. I didn't think I could afford the 50-135mm to begin with, hence considering the 70-200mm. At the price I paid (£639) I think it was well worth having.

A brief rummage on the web suggested that something around the 100mm mark is ideal for rallying, certainly I found 28-80mm to be a perfect range at the last winch challenge event I went to (where you can get as close as you like, just don't stand in front of/behind/right next to cars or in the danger zone for a snapping winch cable). A slightly longer lens with superb IQ and weatherproofing should be perfect when the cars are moving a bit faster and slightly further away!

I'm not sure. In my experience I get faster AF the larger the aperture. On the 35/2.4 it's very quick, with the 100-300mm it's prone to hunting at the long end and with a 150-500mm Bigma I borrow occasionally it fails to lock focus most of the time. It seems that f2.8 or faster produces much better AF than f5.6 or slower (the Bigma is f6.3 or something like that at 500mm?)

Bear in mind that the K-m was my first AF SLR of any sort (I had a K1000, P30 and P30T before) so I've nothing to compare to. It reacted fast enough to catch jets at RIAT last year with the old 100-300mm, so providing the 50-135mm is slightly faster it should be fine. I'm more bothered about it locking focus quickly than the time taken to turn the ring, given most of my subjects will be at about the same distance and the lens will only need a fine adjustment between shots.

Yep, this is rather turning into "convince me not to buy a 50-135mm"

I've just been watching some Youtube videos of the AF speed and it doesn't seem too bad. While my K-m isn't WR sealed I do have a long-term plan to buy a good used K7 when prices drop a bit, at which point it'd become superb for forest rally stages (it generally rains at least once, and a camera/lens which don't need to hide in a bag at the first sign of damp would be great).

I'm used to shooting with manual focus lenses, so AF speed shouldn't be too much of a problem. I did see the Tamron was sharper than the Sigma but it seems to be in short supply at the moment? Whatever I buy will get its first proper outing in a couple of weeks at Goodwood FoS.

I notice SRS have the 50-135mm listed on ebay as "4 remaining" so they obviously have stock and the price is right. I am very likely to buy one now as I just think it'll be more use to me. I know I like fast short telephoto lenses (have enjoyed many walkabouts with a 120mm or 135mm on film) and the 50-135mm seems something of a legend in that area.

I also find myself thinking that a DA* lens is a better investment than a 3rd party one - SRS currently have a used 50-135mm for £30 more than the price of the new ones!