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03-30-2011, 07:15 AM   #16
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QuoteOriginally posted by Class A Quote
... Most modern zooms are vari-focal ...
Not in my experience.

Vari-focal zoom lens can cost less to manufacture than par-focal zoom lens. Perhaps, most modern inexpensive zoom lenses are vari-focal. I don't know.

I do know my first version Sigma 2.8/17-35 EX HSM is par-focal. That FF lens is very very close in performance to my prime lenses in that focal length range, I have a difficult time seeing any differences even when pixel peeping . Later versions of that lens only cover APS-C...

03-30-2011, 07:48 AM   #17
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K-x. Almost no PP. Thanks for the comment.

Versatile lens. You use yours for landscape, I use mine almost exclusively for indoor portraits when I simply cannot "back up" to a traditional or even 50mm portrait length. I can get up close or stand back and still get a very good 2.8. At 5.6 (my favourite portrait f-stop) the lens is in prime territory. In lower light and when I want a bit more contrast and DOF control I do switch to the FA 50/1.4. But the 17-50 is easily an all-around performer of substantially higher quality than the kit lenses.

Phoptozone rates the Tamron very high, as does the always flaky but highly entertaining Ken Rockwell.

I own 3 Tamrons and have had no QC issues with any of them but I will not discount that ALL 3rd party lens suppliers have issues and is part of the risk of purchasing non-OEM. Test thoroughly upon receipt and be prepared to exchange.

I find the Tamron 17-50 to be very good value. It's a good, solid piece of hard-working glass. They nailed this lens and the Di 90mm Macro IMNSHO.

QuoteOriginally posted by Jewelltrail Quote
Great shot--on which body did you get this one? I have taken thousands of shots with the 17-50--it is an awesome lens. I used it almost exclusively for landscapes, it has excellent center and border sharpness.

As far as a comparison to the Sigma 17-50 os HSM, the Tamron is better wide open & controls barrel distorions a little better. I used to think the Sigma was sharper, but then realized the review for the Sigma 17-50 is on the Canon 50d APC, whereas the MTF scores for the Tamron were from the older 10 MP D200. Someone here can do the conversions for us if they wish. What I'm getting at, is the sharpness between the 2 lenses is probably not significant. Vignetting is controlled better with the Sigma lens.

You will pay a lot more for the Sigma, mainly for OS & HSM. I can't see paying more for OS, when Pentax bodies already supply this, but am sure some will like the HSM upgrade.

I would put my money down on the Tamron again, wihtout hesitating.
03-30-2011, 10:49 AM   #18
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QuoteOriginally posted by Armanius Quote
Ok, I decided to take the plunge and ordered both the Siggy and Tammy 17-50. I'll see which one I like better and report back. Hopefully the cheaper one!
I think that you will like either. I have the Tammy and a friend of mine has the Sigma, both work very well. The thing that tilted me to the Tamron was the six year warranty. Very good lens and very sharp, with good contrast on my K10.
03-30-2011, 12:20 PM   #19
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QuoteOriginally posted by jimH Quote
I think that you will like either. I have the Tammy and a friend of mine has the Sigma, both work very well. The thing that tilted me to the Tamron was the six year warranty. Very good lens and very sharp, with good contrast on my K10.
Thanks! That's good to know. I should be getting them this Friday. So I can play with them over the weekend.

03-30-2011, 03:36 PM   #20
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QuoteOriginally posted by Armanius Quote
Thanks! That's good to know. I should be getting them this Friday. So I can play with them over the weekend.

it'll be interesting to hear your thoughts, I tried both in store and couldnt decide, have to say the sigma's build quality felt better in my opinion. I'm also considering the sigma 17-70 2.8-4 macro os hsm for the extra reach.

Btw armando, your signature is full of very drool worthy gear! very jealous ;-)
03-30-2011, 05:48 PM   #21
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QuoteOriginally posted by Class A Quote
That's because it probably isn't a parfocal zoom (although there are statements to the contrary. Most modern zooms are vari-focal, i.e., require a focus adjust when the focal length is changed. I know that my Tamron 18-250 certainly is not a parfocal zoom.

For your application, an old, parfocal MF lens might be a better choice. Maybe your Tamron copy just needs checking? Others seem to think it is a great lens for video.
Interesting.

I've found it to be a problem myself, especially on my Pana GH1, where you can't expand focus once you hit record.

Effectively guessing focus during a shoot isn't a whole lot of fun!

Given the crop factor of the GH1 the 17-50mm seemed to be the best option for a do it all lens. It's sharper wide open than my Sigma 24-60mm f/2.8, and a better focal length than it too.

It should still be under warranty, but that involves shipping the bugger abroad for a while
03-30-2011, 06:09 PM   #22
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Does the Tamron 17-50 have an aperture ring, or totally camera control?
03-30-2011, 09:06 PM   #23
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There is no apeture ring on the Tammy, I have mine in front of me

03-30-2011, 11:20 PM   #24
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QuoteQuote:
Aristophanes: K-x. Almost no PP. Thanks for the comment.

Versatile lens. You use yours for landscape, I use mine almost exclusively for indoor portraits when I simply cannot "back up" to a traditional or even 50mm portrait length. I can get up close or stand back and still get a very good 2.8. At 5.6 (my favourite portrait f-stop) the lens is in prime territory.

I see the flash fired--is that on-board flash?

Having taken 15,000 shots with the lens, I can say it is in "Prime territory" at other apertures besides 5.6, but 5.6 is the sweet spot. The borders are amazing, especially when you consider you have a 17-50 range, @ 2.8. It is amazingly consistent, throughout the zoom & aperture range.

If I had a ton of money to blow, I might buy 3 excellent primes to cover it, but I would lose the handiness of 1 lens, especially on hikes. When I learn to PP, I'll go back to many of these Raws with the 17-50 and get incredible shots.
03-31-2011, 01:55 AM - 1 Like   #25
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QuoteOriginally posted by Aristophanes Quote
I own 3 Tamrons and have had no QC issues with any of them but I will not discount that ALL 3rd party lens suppliers have issues and is part of the risk of purchasing non-OEM.
Why are you excluding OEM equipment?

A forum member went through five DA* 55/1.4 and couldn't find one that worked well. Maybe one cannot exclude the camera playing a part in this but DPReview went through three DA* 55/1.4 copies as well and all of them had issues. The UK Pentax distributor even knew what the lenses were for. The QC issues of the Pentax 16-50/2.8 are legion and range from decentering to early SDM failures.

There are very nice Pentax lenses but Pentax doesn't seem to provide better QC than third-party lens manufacturers.

Last edited by Class A; 04-01-2011 at 05:20 AM.
03-31-2011, 07:46 AM - 1 Like   #26
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QuoteOriginally posted by Jewelltrail Quote
I see the flash fired--is that on-board flash?

Having taken 15,000 shots with the lens, I can say it is in "Prime territory" at other apertures besides 5.6, but 5.6 is the sweet spot. The borders are amazing, especially when you consider you have a 17-50 range, @ 2.8. It is amazingly consistent, throughout the zoom & aperture range.

If I had a ton of money to blow, I might buy 3 excellent primes to cover it, but I would lose the handiness of 1 lens, especially on hikes. When I learn to PP, I'll go back to many of these Raws with the 17-50 and get incredible shots.
Not onboard flash. The flash is remote triggered and was in a corner about 10 feet away, bounced off the ceiling. Pentax 360 flash.
03-31-2011, 02:49 PM   #27
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Yahoo, lens showed up today. Now to go try it out.
03-31-2011, 09:58 PM   #28
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QuoteQuote:
ClassA: A forum member went through five DA* 55/1.4 and couldn't find one that worked well. Maybe one cannot exclude the camera playing a part in this but DPReview went through three Da* 55/1.4 copies as well and all of them had issues. The UK Pentax distributor even knew what the lenses were for. The QC issues of the Pentax 16-50/2.8 are legion and range from decentering to early SDM failures.

There are very nice Pentax lenses but Pentax doesn't seem to provide better QC than third-party lens manufacturers.
My comments in no way reflect upon Aristophanes. ClassA, from where I sit, you raise an issue which is seldom addressed +1. I often see epidemic Pentax bias, with "bias" possibly too gentle a word to describe the phenomenon. However, this is Pentax Forums & not Sigma or Tamron forums--this, by itself, explains a lot it. After all, the Yankeees in Yankee stadium, are discussed in a uniquely different way than they are in Fenway Park.

Of course, this is still a great forum, and better than many others.

Last edited by Jewelltrail; 04-01-2011 at 02:58 AM.
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