Which is better for street photography ?

and overall sharpness ?

Don't get seduced by the idea of a Ltd to the exclusion of other lenses. I had the Tamron 17-50 and can say it was a superb lens on my K20 but quite big so I stopped using it (and sold it). I had the Sigma 30/1.4 which is a good length but I didn't use that as I had the Pentax 35/f2 which was a superb lens on the K20 (so I sold it). Any of those lenses were fine for street.

I also have the 21 Ltd and 70 Ltd which I find are most used on my K5 as the K5 seems to love the 21 more than the K20 did. They are great lenses and so small and light but the 35/f2 is also very good. I have a 50/1.7 A which I don't seem to get on with very well and if I need a 50 I use the quite bulky Sigma 50/2.8 macro that I have.

Any lens is Ok for street I find. As has been said very eloquently above it's your mental attitude that will get the good shots not so much the kit.

Once again I use a lot of words and haven't really helped at all!

Basically if you want small lenses then the Ltd's are great. If you don't care then I expect the Tamron 17-50 is the better choice.

Mike

Dr. Mhuni wrote:The 50-135 is now my telephoto lens of choice - and despite its relative bulk I find it an excellent street lens with a handy range and relatively fast speed. This lens is also much used by another accomplished PUFer, David Trout, who gets superb results from it in a street context (and in the UK). I imagine it's David's most used street lens'quote]

You're quite right Andrew, I mainly use the 50-135 but quite often the DA*16-50 comes into use in the street.
I think your style of street photography comes into play when you chose focal length. Many people (like Tim Houghton) prefer the wide angle for shooting at hip level when doing grab shots.
I prefer to find a suitable location which will give me a good backdrop and wait for the right figures to walk into the frame. I like to compose and pre focus and then lurk.
For this a longer lens is essential. And as I've said on a previous occasion, the longer lens gives you a head start if the subject kicks off.
David

PPG: http://www.pentaxphotogallery.com/artists/davidtrout

I will let you know.
I am off to Tallinn in May with the intention of doing various types of photography. I will only be taking primes (apart from the long end) so will have the choice of 21, 28, 35, 40, 50 and 55. Could be a pain with keep changing lenses, but then again it might not.