lens for portrait

Hi all in looking at buying a lens for portrait work,
im looking at the Pentax SMC DA 16-45mm F4 Lens,
also the Sigma 17-70mm F2.8-4 DC Macro OS HSM Lens,
also the Sigma 18-50mm F2.8 EX DC Macro Lens.
and the Tamron SP 17-50mm f/2.8 XR Di II LD,
my budget is no more than £350,
any one has one of these an can comment on quality i would be most greatfull.
If anyone knows of any other lenses i should look at,
im not interested in primes at the moment,
as im tight for room and need a flexible lens.
Thanks in advance.

I have Tamron 17-50. It's excellent, except often needs an AF adjustment, so I only recommend it for the K20D and K-7 cameras as they allow AF adjustment for individual lenses.

16-45mm is a bit short for portraits. I think you would be happiest with a Sigma or Pentax 17-70mm.

You could have a prime in addition if affordable. One wouldn't take up much room.

thanks pete. i did look at the pentax 17-70mm but it is to pricey,
also looked at a number of reviews and the sigys come out about the same and the tamron always seems to do a tad better.
i will be using a k7.
any body with any pics taken ith the lenses fancys posting them feel free.

The Tamron 28-75mm F2.8 would be a better range in my opinion than the 17-50 link
Review link

I agree with Stefan, the Tamron 28-75 (set at 75mm) would be the better for portraits and the constant F2.8 is a nice touch. When converted 75mm would come close to 109mm which in MHO would be the prime for 135 film use. I have a Tamron 28-75 and use it constantly, it is probably my most used lens. I highly recommend it. Over here they tend to be a bit pricey when new, but you should be able to find a good used one at reasonable cost.

Good luck,

Stephen

You should instead consider an A 50/1.7, which might set you back 40 sterling. This would give you an excellent field of view for portrait work and much more depth of field control.