Which wide - short tele lens to go for?

I have read inumerable test reports over the last few days and at least I have boiled it down to 3 lenses more on grounds of cost but they all seem to be decent lenses.
I take a lot of moving subjects, trains, so I am looking for something with a faster maximum aperture than the f3.5 - 5.6 of the 18-55 kit lens which I believe is quite a decent lens at mid-apertures?

The Tamron 17-50 f2.8 has the fastest aperture of all and seems to be very good at maximum to mid apertures which I would be using a lot anyway.

The Sigma 17-70 f2.8-4 seems to have the best image resolution across the entire range but is a bit slower than the Tamron but it does go up to 70mm.

The Pentax 16-45 f4 is the slowest lens, is shorter at 45mm, on test perhaps not quite as sharp or have the same resolving power as the other two?

Apart from sharpness/resolution what else is there to consider? Image brightness and contrast, are the Tamron and Sigma as good as the Pentax? The colours I get now with the KX and kit lens seem more vivid than some Canixon offerings, are 3rd party lenses as good in this repect as Pentax lenses?

With a 3rd party lens am I paying for spec I don't need? The Sigma for instance has an anti shake system built into the lens which I don't need. Is it counter productive to have two anti shake systems, one in the camera, one in the lens?

In various test reports and user comments some or all of these lenses seem to suffer from poor QC, how do you check this? Setting the camera on a tripod and photographing a newspaper or something similar? If you find you have a bit of a duffer will retailers replace it?

I suppose everyone has their preferences but in the end it may come down to a fast maximum aperture....

If you can find one that looks in good condition snap up a Sigma 28-70 AF Epsilon. It is f3.5 - 4.5 so whilst no faster at the wide end it stays fast at the tele end. It is also fast A/F.

I got mine for £15 plus postage earlier this year but I've not seen another advertised since.

I am more than happy with the image quality and you will find many shots, including one taken from a moving carriage on the Ffestiniog Railway, in my Portfolio Gallery.

Build quality apparently varies, and it will depend on it's prior use as well, but mine is as good as new !

Good hunting

Peter

I don't have personal experience yet but I have been following comments about all these lenses on the forum for some months as it's probably the next sort of lens I will get.

If I were to buy now based and what I have read I would get the Tamron, like you I would want to be able to go that fast when needed.

The main difference will be loss of those Pentax colours/contrast, some say that it's not important as you can sort it in PP, I don't really agree with this. Personally I find the Pentax DA17-70 excellent, sharp and very nice colour/contrast..I've owned the Sigma 17-70 in the past and it's as sharp as the DA17-70, doesn't have those colours though

Simon

I agree with Simon.

I recently bought a Pentax 17-70 from a forum member to replace a Tamron 17-50, mainly for the extra reach, which reduces lens swapping in the field. I'm loving the IQ and, as Simon says, the distinctive Pentax colour rendering.

When I first got the KX both my Wife and step-daughter commented on the colours so it's not just about maximum aperture. I thought it was the sensor that gave that gave those punchy colours.
It's a good point about having the 17-70, sometimes 50mm isn't quite long enough.
The Pentax lenses are more expensive, I think that I will get the K5 body and look around for a good Pentax lens second hand.
By the way, just how good are the kit lenses? I haven't seen any really large prints off my images but what I haev seen look very good.

I have quite happily used the kit lenses for A3 competition prints and they have looked every bit as good as anything else.

We used the 18-55mm, the 16-45mm and now the 18-135mm.

Have to say some of my best pictures are with the kit lens, get the focal length and aperture right and they can be very very sharp with nice colours.

I can't comment on the Sigma or Tamron lenses as I've never used them. I can give a recommendation for the Pentax 16-45, which is sharper than the 18-55 kit lens, particularly at the edges of the frame and performs well at its F4 maximum aperture. The 16-45 is my stock landscape lens and is well up to this task.

It's not a fast lens, but this is less important given the quality of sensors nowadays and the excellent performance available at higher ISO's. The 16-45 is not too expensive, you should be able to pick a mint second hand copy up for around £150.

Regards
David

Having read the review of the 16 - 45 f4 on ephotozine I think I will hold out for a good used one coming up for sale, it seems to be a cracking lens.

Don't discount the Tamron 17-50 2.8... It doesn't have quite the same colour rendition as Pentax lenses (it's cooler and sometimes requires a bit of punch) but it's a great bit of glass, razor sharp and produces on demand...

I only sold mine to help fund the move from K-x to K5 and would certainly consider re-buying it in the future... (although a wide to mid zoom is not on my priorities list)

If you want to add a 4th to your list, consider the Sigma 18-50 DC EX.
Like the Tamron, it has a constant f2.8 through the zoom range.

Been using mine for some years now, highly recommended.
They seem quite rare in the classifieds though..

I went out the other day when it was blue sky and sunshine but when I got to my chosen location, you guessed, it was the only place in the North West which was cloudy. It was too late to move and in the end I had to use 1600 ISO whereas with a F2.8 maximum aperture I could have used 400 ISO. So, I am edging towards the Tamron but some reviewers question the QC on Tamron lenses, have owners of this lens experienced any QC problems?

Wouldn't bother me. Buy from an authorised stockist like SRS and you get a 5 year guarantee from Tamron. If I needed f2.8 at the short end it would be my upgrade.

I dont know if this helps, but until recently I had the 16-45 and the Tamron 17-50. To fund the purchase of a K5 one had to go.

To be honest after doing many comparison shots there was little to choose between the two.

At the end of the day I kept the Tamron on the basis that it was 2.8 and is a bit sharper than the 16-45.

I dont think you would be too unhappy with either.
ps I have a 55-300 which is a great lens for the medium to longer shots.