[Ubuntu_user]

Okay here's what I want to know:

Tamron's 17-50 AF speed and build quality in comparison to Pentax's 16-50.

I love my 16-50 but if the AF were faster on the Tammy, then I may contemplate selling the Pentax in exchange for the Tamron.
I've been running the Tamron 70-200mm and noticed that AF is much quicker with it than my 16-50, so is it the same with the 17-50?

Also, when zoomed in (so that the lens barrel is extended) how far does the tamron stick out?

Your comments are appreciated.

[Deimos]

Okay here's what I want to know:

Tamron's 17-50 AF speed and build quality in comparison to Pentax's 16-50.

I love my 16-50 but if the AF were faster on the Tammy, then I may contemplate selling the Pentax in exchange for the Tamron.
I've been running the Tamron 70-200mm and noticed that AF is much quicker with it than my 16-50, so is it the same with the 17-50?

Also, when zoomed in (so that the lens barrel is extended) how far does the tamron stick out?

Your comments are appreciated.

I cant answer your Qs yet, I have a Tamron 17-50 2.8 at home, just waiting for my k-r to arrive any day now....

Build quality seems great. I dont have any $1000 lenses to compare it to but it is eons ahead build-quality wise of the old d60 kit lens I had...seems very well built and solid.

[Jonathan Mac]

The Tammy is neither fast nor slow to focus, and it´s noisy as it´s camera-driven. My kit lens focuses faster, the 55-300 focuses slower. I would doubt it´s faster than the 16-50, and the Pentax will be much quieter.

There are two reasons to go for the Tamron: price and SDM fear. If you already have the 16-50 then these may not really apply. If you´re looking for something that focuses really fast on a Pentax, either go for a prime (or set of them) or wait for the 16-50 mkII, whenever that may come along.

[bigdog104]

It maybe bad form to answer a forum post with a post from another member but I read this awhile back and it really makes me want to look at gettting the Tamron 17-50 as my next lens, please read Peter Zack's enitre post here:

https://www.pentaxforums.com/forums/professional-photography-publications/118...ml#post1225640

"Second, I got a Tamron 17-50mm f2.8 and it's a wonderful lens. Sharp and very good rendering with very fast AF. Made me realize how truly terrible the DA*16-50mm is. In fact I have nothing good to say about that lens and would never recommend it now to anyone. It should be dropped from the line and replaced. Slow focus, SDM issues, excessive barrel distortion, soft corners (does not render flat across the frame) etc etc. Honestly this is a disgrace to the top tier series. The Tamron at half the price is superior in every respect. "

[deadwolfbones]

I loved my 17-50/2.8. AF isn't blazing fast, but it's as fast as any other screwdrive zoom. Sharpness is excellent IF you get a copy w/o FF/BF issues. Mine was crazy sharp at 2.8.

[jolepp]

...
Also, when zoomed in (so that the lens barrel is extended) how far does the tamron stick out?

@18mm 82mm, @50mm 110 mm (from the mount surface, a quick job with a measuring tape). AF seems pretty snappy to me, but having never laid hands on one can't compare with the 16-50. Roughly equal to the kit 18-55, seems to work in low light as long as there is enough of it to shoot handheld. This with the VF, though, LV autofocus is an order of magnitude slower or worse with any lens, I suppose.

[dankoBanana]

It maybe bad form to answer a forum post with a post from another member but I read this awhile back and it really makes me want to look at gettting the Tamron 17-50 as my next lens, please read Peter Zack's enitre post here:

https://www.pentaxforums.com/forums/professional-photography-publications/118...ml#post1225640

have to say I'm also confused
I'm currently contemplating about getting a nice workhorse zoom, but I'm still unable to decide what to get
The things I like on the DA* 16-50 are its quiet SDM, WR and a 16mm wide end, and there isn't really an alternative to that in K mount

[pop4]

There is another option, the recently released Sigma 17-50mm F2.8 EX DC HSM OS. It is a fair bit more expensive than the Tamron, but it does have HSM, which focuses quickly and very quietly. I've also had no problems with sharpness and image quality on my copy.

[Deimos]

I loved my 17-50/2.8. AF isn't blazing fast, but it's as fast as any other screwdrive zoom. Sharpness is excellent IF you get a copy w/o FF/BF issues. Mine was crazy sharp at 2.8.

Regarding the FF/BF issues, which no camera store employee ive talked to has ever seen a return for (5 different shops). It says right in the Tamron 17-50 manual that under certain interior lighting conditions FF/BF is possible.

Im pairing mine with the k-r so luckily it has AF adjust, but ive read at least two reports of ppl having to adjust the AF to -9 in order to have 2-3 diff Pentax limited lenses have correct focus so its not just Tammy..

[Ubuntu_user]

There is another option, the recently released Sigma 17-50mm F2.8 EX DC HSM OS. It is a fair bit more expensive than the Tamron, but it does have HSM, which focuses quickly and very quietly. I've also had no problems with sharpness and image quality on my copy.

Ah ha! Forgot about that option. HSM would be nice... If it (the Sigma) is as good as the Tamron IQ wise, I just may go for it...

[Ubuntu_user]

Hmm... Anyone know how the 17-50 (Tammy) AF speed is compared to it's big brother the 70-200mm?

[Deimos]

Ah ha! Forgot about that option. HSM would be nice... If it (the Sigma) is as good as the Tamron IQ wise, I just may go for it...

There is also a newer version of the tamron 17-50 with OS and I think HSM (well the tammy equivalents)

[Ubuntu_user]

There is also a newer version of the tamron 17-50 with OS and I think HSM (well the tammy equivalents)

But this version you're talking about isn't available in Pentax mount, is it? Will it ever be?

[Deimos]

But this version you're talking about isn't available in Pentax mount, is it? Will it ever be?

oh not sure to be honest. I bought the original version because I read various reviews suggesting it was better than the "upgraded" replacement in terms of IQ etc. I think its the same deal with the Sigma.

[Miguel]

You may not want that model anyway. In the Canon universe, the newer version with built-in IS is considered inferior optically.

I've owned the original model for both Pentax and EOS mount for the past few years. It's a real bargain. Not perfect, but plenty good enough for my work purposes. There has been a long line of complaints on all platforms about inaccurate focusing. A moderate focus adjustment (after diagnostic testing) on my K20D fixed the problem permanently. I've had no issues with my 7D.

This is one of the sharper tools in the box. The build quality isn't great (3.5/5) but I think that's just due to plastic being the interface to the touch, including a cheesy lens hood. The lens itself is not superlight however.

My only issue with this lens is the rendering of certain colors: greens, blues, violets. They're a little "off" from my Pentax ideals. Fixable with a Lightroom preset or two. Interestingly on my Canon, the colors are just fine. I have this unfounded theory that Tamron used Canon and Nikon bodies to determine acceptable reference colors for rendering (for obvious reasons) and that's that.

The reality is that the Pentax platform excels in primes; the available zooms are mostly average with a couple of exceptions. So the Tamron is your best bet for this range. Another suggestion would be the DA 16-45mm; well-proven, but f4. Sigma makes an 18(?)-50mm f2.8, but I'm ignorant about it. I prefer my zooms in a popular range to be f2.8.

M

But this version you're talking about isn't available in Pentax mount, is it? Will it ever be?