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02-14-2013, 04:45 PM   #1
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Sigma 17-50/2.8 vs DA16-45 or 17-70

So I've found a Sigma 17-50 (with OS) for a pretty good price. I've been considering replacing my kit lens for quite a long time and recently bought a DA15 Limited. It's an amazing lens but I find myself wanting to zoom in some. I was shooting some landscape yesterday with my DA15 and M50/1.7, and found the gap to be quite huge. And since I don't have the money to buy 2 or 3 primes for that range, I've decided to look for a good zoom lens (for the nth time). A few months ago (before deciding on the DA15) I was debating between the 16-45 and 17-70 (both Pentax) and couldn't choose because the 17-70 seemed of higher quality and had SDM, but SDM is notorious for failing... Now I've got the Sigma 17-50 in my sights, which was rated higher here than the Pentax DA* 16-50.

The 16-45 and 17-70 are both cheaper, and I would have to get the Sigma used (or wait a while and save up more $$ for a new one). I've heard some things about the stabilized version being worse than the non-stabilized one. Is that true? Also, does it have common back/front focusing issues like a lot of non-Pentax k-mounts?
Between the 16-45, I would probably choose the 17-70 if it wasn't for the common SDM issues. I like the extra range.

As for use: I won't be using it at the extreme wide end. I have my DA15 for that. I would use the 20-70mm range (or 20-50), mostly in the 25-40 range.

I also keep coming back to the possiblity of a 28/35mm prime but I am willing to compromise the sharpness of a prime for range and usability -- at least for now.

EDIT: One last thing -- flare resistance. I know I won't be able to get the 15mm's amazing flare resistance from any of these lenses, but I am wondering which one is best in that field.

02-14-2013, 05:06 PM   #2
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In the end it depends on your own requirements so I can only offer what I am thinking for myself...
I don't have a Pentax 16-45 or 17-70 but I do have Sigma 17-70 (which has similar image quality to Pentax 17-70 according to reviews) and 28mm, 35mm, 50mm primes (manual primes).

I like shooting with primes and I like the IQ and colours compared to the Siggy 17-70. However recently I got the Sigma 10-20 f3.5 and its changed my view on things a bit - image quality is really good but the flexibility is there too. I'm now thinking of saving for a Sigma 17-50 f2.8 for the shear convenience of a take anywhere lens.
I would also consider DA* 16-50 SDM except for me:
1. Its a too expensive at the moment
2. Personally I'm still worried by the SDM
02-14-2013, 06:37 PM   #3
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I prefer the Pentax glass over the Sigma. I haven't had any SDM problems, but that doesn't mean you won't (or I won't in the future). Nevertheless, I enjoyed having the longer reach of the DA17-70, and I normally shot it at f/4.5 or f/5 (since it was good close to wide open).

I came close to getting a DA16-45 at some point, but I eventually got a DA*16-50 and it became moot. Since you have the DA15 you don't really need the DA16-45, which is more biased toward the wide end (unless you find you like the rendering better in sample images).

So, personally, I wouldn't bother saving up for the Sigma. Enjoy the DA17-70 for a year or two. Then you can decide whether you want to stay with it or want something more. But in the meantime it's a good lens.
02-14-2013, 07:46 PM   #4
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I have both sigma lenses. In my opinion the 17-50 sigma is superior by a long shot. What the sigma 17-70 does really well is semi macro. If you want an all in one lens then the 17-70 does a good all round job but is not in the same class as the 17-50.

I would regard the 17-50 as professional quality (my copy anyway) and the 17-70 as a run around.

I didn't get the pentax 16-50 because of its past issues and I can buy 2 sigmas for the price, so if I kill the sigma, I can get another for the same cost all up.

02-14-2013, 07:46 PM   #5
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I shoot mostly with primes but have the DA 17-70 for occasions that I don't want to be changing lenses or when I take both bodies. I like the extra range and have previously had the 16-45, 16-50 and Tamron 17-50 f2.8. All three were OK and the first two were traded for primes. I had the DA 18-135 and used it for a trip to Maui but sold it after because of lousy performance in the corners at the long end. I got a great deal on the 17-70 and like it's IQ for a zoom. Personally I think the SDM failures are not as frequent as some people seem to make them out to be and like many things in life , you take your chances.

The extra reach over the zooms that go to 50mm is useful for me, but your needs may be different. I shoot more with my 5 limiteds and 3 other primes but like a nice zoom for times that I don't want to change lenses. Good luck in choosing.

P.S. The quiet SDM is handy on occasions.
02-14-2013, 08:47 PM   #6
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Don't forget the Sigma 17-70 which is what I have my eye on. From what I have seen, it also outperforms its Pentax counterpart. Plus you won't have to worry about the SDM.
02-18-2013, 01:58 AM   #7
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QuoteOriginally posted by NitroDC Quote
I would use the 20-70mm range (or 20-50), mostly in the 25-40 range.
Then how about Tamron 28-75? Good IQ, constant f2.8, good FL range.
02-18-2013, 03:52 PM   #8
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QuoteOriginally posted by simico Quote
Then how about Tamron 28-75? Good IQ, constant f2.8, good FL range.
Right. Now I've got even more to pick from.

I've decided possibly not to go with a 16-45 or 17-70 as I want the faster aperture from the 2.8's. The Tamron 17-50 was in my sights but it seems to have way too many back/front focus issues and reviews seem better with the Sigma.
The 28-75 is also very tempting. They seem to be equal in terms of sharpness but the Sigma looks to have more microcontrast and a more interesting color reproduction, also HSM (as opposed to screw AF). The Tamron 28-75 color reproduction looks kind of flat (at least from the samples in the review database). I do like the extra range from the Tamron, though.


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