I don't see why you'd buy the *300 and the 60-250 unless the *300 was for commercial work. The IQ of the 60-250 is so high - right up to 250 (and it works so well with the AFA x1.7) that it makes the difference in both IQ and the extra 50mm superfluous to all except those needing the absolute highest quality. Certainly for another 1k quid !

Thanks Simon - been there and commented :-

Between these, Adam's review and other shots I've seen I think the 18-135 fails to deliver sharp enough shots for my liking and I'm going to skip it.

AND (in response to someone who said : I think it is sharp enough for day to day use, I dont realy think one could/should expect too much form a lens like this...)

That's the problem though - it's not really priced as a 'day-to-day-use' lense. I already have a Sigma 18-125 that hasn't seen the light of day for 6 months at least.

If the 18-135 is not a huge improvement on the Sigma (I was hoping it was going to be) then I don't see the point (for me) and I would rather pay the extra and go for a DA* lense.

*sees a business opportunity*

Not sure how this may relate to the UK/USA but over here (SHanghai) the K5 + 18-135 costs £1,200 (£900 for K5 alone) so that is of course £300 for the lense.

Great lens ..... I love mine and I'm sure you'll love yours too !

Exposure Plot

I've just run this again to see what I'm shooting (it's a free windows software program from www.vandel.nl runs fine on my Mac using Crossover). Some interesting results !

Run on my Picture folders. What an eye opener, I'd never have guessed !

1. 17.62% @ 90 mm (guess that would be all my macro shots with the Tammy 90)
2. 10.35% @ 43 to 50mm (43 Ltd & FA 50/1.4)
3. 9.76% @ 10mm (Sigma 10-20)
4. 4.01% @ 11mm (Sigma 10-20)
5. 3.97% @ 60mm (various)
6. 3.87% @ 20mm (Sigma 10-20)
7. 3.69% @ 80mm (55-300)
8. 3.48% @ 300mm (55-300)

ISO

400 - 22.72%
800 - 16.55%
200 - 10.47%
100 - 9.92%
125 - 8.86%

Aperture
5.6 : 17.91%
4.0 : 13.47%
8.0 : 9.82%
1.4 : 5.50%
2.8 : 4.92%

Shutter
1/180 : 12.48%
1/200 : 12.48%
1/30 : 7.45%
1/125 : 5.72%
1/80 : 5.36%

Download it and give it a go !

Zeiss Sonnars : sorry not the man to ask, some very knowledgeable lads on MFLenses though.

M42 adapters : I have 3 and luckily haven't had any of the horrible (shavings in the camera) issues some people have experienced. However I now use the Pentax made adaptor exclusively - it is the highest quality one and just takes 4 or 5 secs to put on / take off instead of the messing around for 20 - 30 secs of the 3rd party adapters.

As Dangermouse said : the 50mm & the 135mm were THE standard lenses in the film era and so there are lots of superb 50s and 135s out there.

I have two MF 135s :
SMC Takumar 135/3.5 - and I love this lens, maybe just a shade more than my Carl Zeiss Jena Electric MC Sonnar 135/3.5 (which I guess actually more people would appreciate) but both are wonderful lenses.

Kris - it's called Exposure Plot. A windows program it runs well on my Mac using Crossover.

I've the Tamron 90 - fantastic lens - but to get you going in macro just reversing a prime lens (that 50mm you're going to get) will work well and just cost you a fiver for the reversing ring.

Other than that go the official websites for Pentax, Tamron & Sigma and you'll be able to find the definitions for the terminology used by those manufacturers.