I just got the Sigma 70-200. I don't have experience with the other lenses you mention, but as a basis for comparison I've been using the Digital Zuiko (Olympus) 50-200 for the past three years. The Zuiko is one of the best zooms ever made in terms of build, wide open IQ, auto focus accuracy, etc. From the moment I put the Sigma on my K200D, I was impressed. The HSM is quiet, very fast. It is totally useable wide open, even better at about F4.0. I wouldn't hesitate unless you had to have weather sealing. Save some money and own a great lens with a 4 year warranty.
There's also the new Sigma 50-150, which might challenge the 50-135.
There are advantages to the Pentax, though IQ differences between the 50-135 and the Tamron 70-200 are hard to appreciate - both are stellar lenses. The Sigma 70-200 has been commented to have less contrasty images but otherwise comparable.
Hard to advise - I thought you answered your own question by wanting some length and cost-effectivenes (70-200's the winner), though size would be a problem (it's significantly bigger and heavier than the 50-135) and it's not weather sealed.
Looking at your lens mix and your stated purpose, I'd suggest you consider several others choices (I don't know the AUS price)
1. The DA*16-50 f2.8
2. DA 17-70 f4 or Sigma 17-70 (?)
Any of these would be an upgrade from your kit lens and should deliver better IQ for your applications. You've got wide and tele covered so upgrade the mid range. Personally I love the DA*16-50 for a lot of reasons and a lot of uses.
Pentax 50-135 and sigma 70-200/2.8 are both $800US at BH photovideo. With the aus$ at 80c US thats right on the threshold for copping 10% GST.
Sigma 50-150/2.8 and tamron 70-200/2.8 are both under, leaving more money to get something else (not in the same shipment), like a tamron 17-50/2.8 or 21/ltd
Cheers
The Tamron 70-200 does not come with an international warranty if you buy from the USA, only way around this is to purchase a "Sagemax" warranty.. B & H code NESCL3600..
I bit the bullet and bought locally, for $1175, comes with two year maxwell warranty, also a few people have had QC issues with this lens and sending it back to the US would be painful.
I guess I would favor getting the Da 50-135. It has great sharpness and contrast and is far and away the smallest of the lenses that you have there. On the other hand, the other thing to think about would be to get a small pancake prime -- probably the 70 and experiment using that. I'd suggest the 40, but with the 50 you are pretty close in focal range there.
The Sigma Corporation is pleased to announce the launch of new SIGMA 18-250mm F3.5-6.3 DC OS HSM.
The SIGMA 18-250mm F3.5-6.3 DC OS HSM incorporates Sigma’s original anti-shake compensation function, with a 13.8 times zoom ratio. As opposed to having an anti-shake function in the camera body, this lens’s Hybrid Optical Stabilizer provides not only an anti-shake function for the camera body, but also compensates for image shaking in the view finder as the Optical Stabilizer is built in to the lens. Incorporating four Special Low Dispersion glass elements and three aspherical lens elements provides excellent image quality throughout the entire zoom range. This lens has a minimum focusing distance of 45cm (17.7 inches) at all focal lengths and a maximum magnification of 1: 3.4 reproduction ratio, making it ideal for close-up photography. An inner focusing system eliminates front lens rotation, making it suitable for use with circular polarizing filters and the supplied petal-type hood. Incorporating super multi-layer coating reduce the ghost in the backlight photography.
I think you should get the 50-135mm for the uses that you stated. After playing around with my 50-135mm for a few days, I noticed that 70mm was really tight for crowded areas such a tourism. I am not sure about street photography, but the wider is usually the better (heard 35mm (normal) range is the best). As for landscapes, the 70-200mm would probably suit you better, but then again, you already have the 70-300mm for that.
A big consideration is if you can handle the weight of the 70-200mm as well. This was a big consideration for me and that's what swayed me to getting the 50-135mm.
1. if you THINK it's heavy, you won't want to use it as much
2. if you don't use it as much, you will be lazy.
3. If you are lazy, you won't take good photos.
:-D
I have a little money to spend on a lens, but am uncertain which one to buy.
The Pentax 50-135mm (possibly a little short at the long end). $1,600AUS ($1,100AUS+postage from Hongkong)
The Sigma 70-200mm (longer reach) $1,398AUS ($998AUS+postage from Hongkong)
The Pentax 60-250mm (perhaps longer than I really need). About $1,200AUS+postage in Hongkong, but have no idea of the price in Australia....
Any other suggestions would be gratefully accepted. But I want, for the money, the best IQ I can get...
I mainly shoot tourism, landscapes and street photography.
My price limit is around $1,500AUS (about $1,200US).
Darius, from your list I read, that you are explicitly looking for the tele photo range. So I won't suggest a 16-50/2.8 or the like. I personally have a Sigma 70-200/2.8 (pre-HSM, pre-Macro version), which is simply excellent. It is one of my two mainly used lenses (the other probably being now the Pentax 16-50/2.8) It is ideal for street scenes, if you prefer a bit of shooting distance (as I do). You can always add a tc to get even longer, and arrive at basically everything the Pentax 60-250 would provide, except on the shorter side.
With the original Sigma 1.4x tc you would be very hard pressed to find any loss of IQ with the 70-200 - I never saw any difference in my pics. But currently the HSM function is not supported by the Sigma tcs, as they rely still on the old scredriver AF.
I never even seriously contemplated the Pentax 50-135, as I find it too short a focal length. If I need a small, unobtrusive lens, I use primes and not a zoom at all. So if you go for the Sigma, an FA 35/2 would be a cheap and very sensible addition to it (as you already have the 50/1.4)