Deciding on new Primary Lens [Pentax 16-85 vs Sigma 17-50 vs Tamron 17-50]

redcat · 12-28-2016, 11:48 PM

The Tamron and Sigma 17-50 are both super sharp and have f2.8 (very useful for low light or bokeh

). Sigma is a little bit better build and rated sharpest zoom for K3 so you can't go wrong with that IMHO

audiobomber · 12-29-2016, 06:24 AM

I researched Tamron vs. Sigma 17-50 extensively, on many websites. Here are my findings; the Sigma is better built, has silent auto-focus and is sharper at wide apertures (this last reason is critically important to me, as wide aperture shooting is the reason I wanted the lens).

I read many complaints of poor focus accuracy with the Tamron. The Tamron is reputed to have better flare performance, but I have not found flare to be an issue on the Sigma in the year or so that I've used it. Sigma focus and zoom rings turn the wrong way, which is annoying.

K-mount is spoiled for choice when it comes to upgraded standard zooms, as shown in this thread; DA*16-50mm, Sigma & Tamron 17-50 f2.8, Sigma 17-70 f2.8-4, DA 17-70, DA 16-85mm, DA 18-135mm. Each has its advantages and disadvantages. Think carefully about what you want from your zoom (range, aperture size, sealing, etc.) and take your pick. Once you have it, make sure you got a good one, check for AF accuracy and decentering.

**UncleVanya** · 12-29-2016, 09:23 AM

The da 16-45 hasn't been mentioned but isn't bad either. The wobble issues aside it is quite wide and the main downside is the limited range.

ScooterMaxi Jim · 12-29-2016, 01:46 PM - **1 Like**

I think all the comments so far are fair. You really should make the decision based on your overall shooting needs, as opposed to the optical concerns on lenses that all measure up fine on IQ.

In differentiating the Sigma and Tamron 17-50s, I agree with Audiobomber overall - and have a couple other thoughts, as well. I purchased the Sigma once it got down to $400 or a bit below. The build is significantly better than the Tamron (my brother had that one); his loosened up a lot under less than heavy use, and Tamron did not see the problem as a warranty issue. I think that's the main issue. Also, the Tamron is known to have considerable field curvature at wide angle / wide aperture. It might not be great for landscape work unless stopped down considerably.

I haven't had the Sigma long enough to pass strong judgment yet. It does everything well, but I'm yet to get excited by a stellar image (my problem - haven't shot anything all that interesting with it yet). I'm still getting used to the overall bokeh, coloration, and saturation, and how best to process the RAWs compared to the Pentax look. Size and weight hasn't bothered me (but I tend to be OK with larger, heavier lenses). It balances fine, and isn't front heavy - at least on the K-3.

**BigMackCam** · 12-29-2016, 02:21 PM - **1 Like**

Originally posted by ScooterMaxi Jim

I haven't had the Sigma long enough to pass strong judgment yet. It does everything well, but I'm yet to get excited by a stellar image (my problem - haven't shot anything all that interesting with it yet)

That's an interesting observation - and one I can relate to, though I'm not certain we mean the same thing. I really like the Sigma 17-50 f/2.8 and still believe it was - by far - the best choice for what I wanted. I have plenty of photos taken with it that I'm happy with after post-processing, but... I dunno, straight out of the camera they feel a bit lacking in character. In my case, it could be that I've developed a liking for older and essentially "flawed" lenses. The Sigma is a fairly consistent performer at all focal lengths - sharp in the center, perfectly decent at the borders wide open, and better still stopped down - and the bokeh is quite pleasing for a normal zoom. Compared to a few of the lenses I like shooting with most, the Sigma is technically a "better" lens...

FantasticMrFox · 12-29-2016, 04:10 PM

I found myself in a similar situation about a year ago - Pentax HD DA 16-85 WR vs. Sigma 17-50 f/2.8 HSM vs. Tamron 17-50 f/2.8 vs. Sigma 17-70 f/2.8-4 vs. Pentax DA* 16-50 f/2.8. Sigma 17-70 (image quality not good enough), Pentax DA* 16-50 (way too expensive for what it offers) and Tamron 17-50 (same as Sigma, but noisy AF) went out immediately, and I was left with the Sigma 17-50 and Pentax 16-85.

I do a lot of outdoor stuff and really wanted the Pentax for the weather sealing and versatile range, but the price put me off. The Sigma offers very good image quality and is faster than the Pentax, at €330 vs. €600 for the Pentax.

My personal experience with the Sigma is hesitantly positive. Image quality is very good, except for strong CA in harsh contrast situations at wide-angle, plus the wide-angle bokeh is atrocious, with double edges (example here).

What annoys me is the focusing. It is swift and manages to grab on fine, but I started to think that there's a problem rather early when I realised that the lens misfocuses (never bothered to check whether front or back) when shooting wide-angle, distance (more than a metre or so away) in less than perfect light. Obviously not to be solved via focus adjustments. I decided that these situations are rare enough not to warrant sending the lens back. Since then most of my images are sharp and in focus, but I also find some that are clearly not focused as they should be. I cannot nail it down to a certain type of situation, but it's definitely worse in bad light.

So ... it is a good lens, but I am not as happy with it as I could be.

ScooterMaxi Jim · 12-29-2016, 04:29 PM

Originally posted by BigMackCam

That's an interesting observation - and one I can relate to, though I'm not certain we mean the same thing. I really like the Sigma 17-50 f/2.8 and still believe it was - by far - the best choice for what I wanted. I have plenty of photos taken with it that I'm happy with after post-processing, but... I dunno, straight out of the camera they feel a bit lacking in character. In my case, it could be that I've developed a liking for older and essentially "flawed" lenses. The Sigma is a fairly consistent performer at all focal lengths - sharp in the center, perfectly decent at the borders wide open, and better still stopped down - and the bokeh is quite pleasing for a normal zoom. Compared to a few of the lenses I like shooting with most, the Sigma is technically a "better" lens...

You expressed my sentiment exactly regarding the Sigma, only you've done so more succinctly. It is my hope that I will find a bit more character in the lens as I understand its strengths. My test scenes resulted in some busy bokeh, but I've been shooting primes a lot lately, so possibly not a fair comparison. One thing I really have to get used to - that I have found surprising - is the silent motor makes it difficult to know if the lens has settled into focus position. Oddly, I feel a lack of confidence as I take the shot; not very rational, but real.

**Canada_Rockies** · 12-29-2016, 04:37 PM

I'm a follower of "Only buy a non-manufacture lens if the manufacturer does not cover the range" quoted in some rather old (not quite as old as I, but close) photo books. I have had the DA*16-50/2.8 since early 2008 or late 2007. The AF still works. Slowly. Sometimes I have to wake it up, the common problem with SDM lenses.

The images from my copy are nothing short of stunning. The focal length range suits me to a T. Even with the K10, cropping 50mm to get "closer" works, and frankly, the focal length, handling WR and such fit me well enough that if the SDM fails, I'll just use it as a manual focus lens. It falls into the "f/8 and be there" category in all honesty. I only pixel peep when figuring how big I can go, so minor details don't bother me.

Some downplay the weight of "good" lenses, and worry about how much you carry around. I am a 1940 model, and I commonly carry my backpack plus a Manfrotto 055 aluminum tripod and RH2 gimbal head around with me. Not counting my lunch and water bottle some find it "way too heavy!" for their taste. The extra few ounces of a 16-50/2.8 are insignificant.

**caliscouser** · 12-29-2016, 04:37 PM

.... and to throw a wild card into the mix.. the DA 20-40 LTD DC WR.

It checks a lot of boxes: weather-sealed, DC motor, excellent build quality, compact, lightweight. Image quality is arguably the best of the bunch, saturated, contrasty, sharp edge-to-edge. Faster than the kit lens, but not quite as fast as some of the others.

Okay the focal range is more limited, but you have to think of this lens as a 'normal' lens with wriggle room each side. Since you have the 55-300 anyway the long end may not be too much of a big deal.
The wide-end, that could be a problem. If you need wide then you need wide.

**UncleVanya** · 12-29-2016, 04:38 PM

On a related note I am trying to pick a lens for my step-dad for his Nikon. I was very surprised to read a lot of reviews suggesting the 17-70 f/2.8-4 was a far better lens than the 17-50 f/2.8 Sigma. The crux of this was that the 17-70 was far sharper. They also mentioned surer focusing but given the difference in wide open aperture over much of the range that's hard to evaluate. Does anyone here think the 17-70 Sigma is a better lens optically than the 17-50?

audiobomber · 12-29-2016, 07:17 PM

Originally posted by FantasticMrFox

My personal experience with the Sigma is hesitantly positive. Image quality is very good, except for strong CA in harsh contrast situations at wide-angle, plus the wide-angle bokeh is atrocious, with double edges (example here).

That example with the double edges is atrocious. I have not seen anything remotely like that in a year of usage. CA performance has been exemplary. Generally Sigmas excel in controlling CA, even with their humbler lenses. I have to wonder whether your 17-50mm is defective.

---------- Post added 2016-12-29 at 21:23 ----------

Originally posted by UncleVanya

On a related note I am trying to pick a lens for my step-dad for his Nikon. I was very surprised to read a lot of reviews suggesting the 17-70 f/2.8-4 was a far better lens than the 17-50 f/2.8 Sigma. The crux of this was that the 17-70 was far sharper. They also mentioned surer focusing but given the difference in wide open aperture over much of the range that's hard to evaluate. Does anyone here think the 17-70 Sigma is a better lens optically than the 17-50?

DXOMark doesn't think so. The 17-50mm scores 30% higher in overall sharpness. https://www.dxomark.com/Lenses/Compare/Side-by-side/Sigma-17-50mm-F28-EX-DC-...6_914_1051_914

**UncleVanya** · 12-29-2016, 07:28 PM

Originally posted by audiobomber

That example with the double edges is atrocious. I have not seen anything remotely like that in a year of usage. CA performance has been exemplary. Generally Sigmas excel in controlling CA, even with their humbler lenses. I have to wonder whether your 17-50mm is defective.

---------- Post added 2016-12-29 at 21:23 ----------

DXOMark doesn't think so. The 17-50mm scores 30% higher in overall sharpness. https://www.dxomark.com/Lenses/Compare/Side-by-side/Sigma-17-50mm-F28-EX-DC-...6_914_1051_914

I wonder if the review I saw was talking about the old version of the 17-50?

Sandy Hancock · 12-29-2016, 08:54 PM

Originally posted by UncleVanya

On a related note I am trying to pick a lens for my step-dad for his Nikon. I was very surprised to read a lot of reviews suggesting the 17-70 f/2.8-4 was a far better lens than the 17-50 f/2.8 Sigma. The crux of this was that the 17-70 was far sharper. They also mentioned surer focusing but given the difference in wide open aperture over much of the range that's hard to evaluate. Does anyone here think the 17-70 Sigma is a better lens optically than the 17-50?

No data, just anecdote and opinion I'm afraid. I'm also talking about older versions of the Sigmas to....

The Sigma 17-70/2.8-4.0 was one of the first lenses I got for my first DSLR (K10D) back in 2008. I was very happy with it, but I was nowhere near as fussy as I am now

I replaced it a few years later for the 17-50/2.8, which I took on a trip to Argentina and used for my early live music work. Although it got the job done I was never entirely happy with its sharpness or fringing, so I compared it for a while against the DA*16-50. The images from the latter were consistently more pleasing despite the lens' well publicised flaws. Four years later I still have the Pentax, and am only now considering moving it on as the DFA24-70 on the K-1 has replaced it.

Hope that's of some help.

audiobomber · 12-29-2016, 09:47 PM

My first day with the Sigma 17-50mm was a year ago. I don't see fringing or CA in these harsh conditions.

More here:

New 17-50mm | Flickr

---------- Post added 2016-12-29 at 23:49 ----------

Originally posted by UncleVanya

I wonder if the review I saw was talking about the old version of the 17-50?

Maybe the Sigma 18-50mm f2.8, which was a bad lens from anything I've read.

**UncleVanya** · 12-29-2016, 10:05 PM

Originally posted by audiobomber

My first day with the Sigma 17-50mm was a year ago. If you can find any fringing or CA in these, let me know. I don't see any.

New 17-50mm | Flickr

---------- Post added 2016-12-29 at 23:49 ----------

Maybe the Sigma 18-50mm f2.8, which was a bad lens from anything I've read.

No -it was the 17-50 vs the 17-70 contemporary. At the time the contemporary was new. Sadly sampling size was a single lens of each - so not great statistically.
Sorry to divert the conversation. Nikon is a distraction in this thread, forgive me.

12-29-2016, 06:24 AM	#17
audiobomber Veteran Member Join Date: May 2008 Location: Sudbury, Ontario Photos: Albums Posts: 6,806	I researched Tamron vs. Sigma 17-50 extensively, on many websites. Here are my findings; the Sigma is better built, has silent auto-focus and is sharper at wide apertures (this last reason is critically important to me, as wide aperture shooting is the reason I wanted the lens). I read many complaints of poor focus accuracy with the Tamron. The Tamron is reputed to have better flare performance, but I have not found flare to be an issue on the Sigma in the year or so that I've used it. Sigma focus and zoom rings turn the wrong way, which is annoying. K-mount is spoiled for choice when it comes to upgraded standard zooms, as shown in this thread; DA16-50mm, Sigma & Tamron 17-50 f2.8, Sigma 17-70 f2.8-4, DA 17-70, DA 16-85mm, DA 18-135mm. Each has its advantages and disadvantages. Think carefully about what you want from your zoom (range, aperture size, sealing, etc.) and take your pick. Once you have it, make sure you got a good one, check for AF accuracy and decentering. Last edited by audiobomber; 12-29-2016 at 08:10 AM.*

12-29-2016, 07:17 PM	#26
audiobomber Veteran Member Join Date: May 2008 Location: Sudbury, Ontario Photos: Albums Posts: 6,806	Originally posted by FantasticMrFox My personal experience with the Sigma is hesitantly positive. Image quality is very good, except for strong CA in harsh contrast situations at wide-angle, plus the wide-angle bokeh is atrocious, with double edges (example here). That example with the double edges is atrocious. I have not seen anything remotely like that in a year of usage. CA performance has been exemplary. Generally Sigmas excel in controlling CA, even with their humbler lenses. I have to wonder whether your 17-50mm is defective. ---------- Post added 2016-12-29 at 21:23 ---------- Originally posted by UncleVanya On a related note I am trying to pick a lens for my step-dad for his Nikon. I was very surprised to read a lot of reviews suggesting the 17-70 f/2.8-4 was a far better lens than the 17-50 f/2.8 Sigma. The crux of this was that the 17-70 was far sharper. They also mentioned surer focusing but given the difference in wide open aperture over much of the range that's hard to evaluate. Does anyone here think the 17-70 Sigma is a better lens optically than the 17-50? DXOMark doesn't think so. The 17-50mm scores 30% higher in overall sharpness. https://www.dxomark.com/Lenses/Compare/Side-by-side/Sigma-17-50mm-F28-EX-DC-...6_914_1051_914 Last edited by audiobomber; 12-29-2016 at 07:27 PM.

12-29-2016, 09:47 PM	#29
audiobomber Veteran Member Join Date: May 2008 Location: Sudbury, Ontario Photos: Albums Posts: 6,806	My first day with the Sigma 17-50mm was a year ago. I don't see fringing or CA in these harsh conditions. More here: New 17-50mm \| Flickr ---------- Post added 2016-12-29 at 23:49 ---------- Originally posted by UncleVanya I wonder if the review I saw was talking about the old version of the 17-50? Maybe the Sigma 18-50mm f2.8, which was a bad lens from anything I've read. Last edited by audiobomber; 12-29-2016 at 10:09 PM.

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12-28-2016, 11:48 PM	#16
redcat Veteran Member Join Date: Jul 2014 Location: Paris Photos: Gallery Posts: 1,939	The Tamron and Sigma 17-50 are both super sharp and have f2.8 (very useful for low light or bokeh ). Sigma is a little bit better build and rated sharpest zoom for K3 so you can't go wrong with that IMHO

12-29-2016, 09:23 AM	#18
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,445	The da 16-45 hasn't been mentioned but isn't bad either. The wobble issues aside it is quite wide and the main downside is the limited range.

12-29-2016, 01:46 PM - 1 Like	#19
ScooterMaxi Jim Veteran Member Join Date: Jul 2009 Location: Minnesota Posts: 1,520	I think all the comments so far are fair. You really should make the decision based on your overall shooting needs, as opposed to the optical concerns on lenses that all measure up fine on IQ. In differentiating the Sigma and Tamron 17-50s, I agree with Audiobomber overall - and have a couple other thoughts, as well. I purchased the Sigma once it got down to $400 or a bit below. The build is significantly better than the Tamron (my brother had that one); his loosened up a lot under less than heavy use, and Tamron did not see the problem as a warranty issue. I think that's the main issue. Also, the Tamron is known to have considerable field curvature at wide angle / wide aperture. It might not be great for landscape work unless stopped down considerably. I haven't had the Sigma long enough to pass strong judgment yet. It does everything well, but I'm yet to get excited by a stellar image (my problem - haven't shot anything all that interesting with it yet). I'm still getting used to the overall bokeh, coloration, and saturation, and how best to process the RAWs compared to the Pentax look. Size and weight hasn't bothered me (but I tend to be OK with larger, heavier lenses). It balances fine, and isn't front heavy - at least on the K-3.

12-29-2016, 02:21 PM - 1 Like	#20
BigMackCam Digitiser of Film Join Date: Mar 2010 Location: North East of England Posts: 20,681	Originally posted by ScooterMaxi Jim I haven't had the Sigma long enough to pass strong judgment yet. It does everything well, but I'm yet to get excited by a stellar image (my problem - haven't shot anything all that interesting with it yet) That's an interesting observation - and one I can relate to, though I'm not certain we mean the same thing. I really like the Sigma 17-50 f/2.8 and still believe it was - by far - the best choice for what I wanted. I have plenty of photos taken with it that I'm happy with after post-processing, but... I dunno, straight out of the camera they feel a bit lacking in character. In my case, it could be that I've developed a liking for older and essentially "flawed" lenses. The Sigma is a fairly consistent performer at all focal lengths - sharp in the center, perfectly decent at the borders wide open, and better still stopped down - and the bokeh is quite pleasing for a normal zoom. Compared to a few of the lenses I like shooting with most, the Sigma is technically a "better" lens...

12-29-2016, 04:10 PM	#21
FantasticMrFox Veteran Member Join Date: Oct 2014 Location: Munich Posts: 2,339	I found myself in a similar situation about a year ago - Pentax HD DA 16-85 WR vs. Sigma 17-50 f/2.8 HSM vs. Tamron 17-50 f/2.8 vs. Sigma 17-70 f/2.8-4 vs. Pentax DA* 16-50 f/2.8. Sigma 17-70 (image quality not good enough), Pentax DA* 16-50 (way too expensive for what it offers) and Tamron 17-50 (same as Sigma, but noisy AF) went out immediately, and I was left with the Sigma 17-50 and Pentax 16-85. I do a lot of outdoor stuff and really wanted the Pentax for the weather sealing and versatile range, but the price put me off. The Sigma offers very good image quality and is faster than the Pentax, at €330 vs. €600 for the Pentax. My personal experience with the Sigma is hesitantly positive. Image quality is very good, except for strong CA in harsh contrast situations at wide-angle, plus the wide-angle bokeh is atrocious, with double edges (example here). What annoys me is the focusing. It is swift and manages to grab on fine, but I started to think that there's a problem rather early when I realised that the lens misfocuses (never bothered to check whether front or back) when shooting wide-angle, distance (more than a metre or so away) in less than perfect light. Obviously not to be solved via focus adjustments. I decided that these situations are rare enough not to warrant sending the lens back. Since then most of my images are sharp and in focus, but I also find some that are clearly not focused as they should be. I cannot nail it down to a certain type of situation, but it's definitely worse in bad light. So ... it is a good lens, but I am not as happy with it as I could be.

12-29-2016, 04:29 PM	#22
ScooterMaxi Jim Veteran Member Join Date: Jul 2009 Location: Minnesota Posts: 1,520	Originally posted by BigMackCam That's an interesting observation - and one I can relate to, though I'm not certain we mean the same thing. I really like the Sigma 17-50 f/2.8 and still believe it was - by far - the best choice for what I wanted. I have plenty of photos taken with it that I'm happy with after post-processing, but... I dunno, straight out of the camera they feel a bit lacking in character. In my case, it could be that I've developed a liking for older and essentially "flawed" lenses. The Sigma is a fairly consistent performer at all focal lengths - sharp in the center, perfectly decent at the borders wide open, and better still stopped down - and the bokeh is quite pleasing for a normal zoom. Compared to a few of the lenses I like shooting with most, the Sigma is technically a "better" lens... You expressed my sentiment exactly regarding the Sigma, only you've done so more succinctly. It is my hope that I will find a bit more character in the lens as I understand its strengths. My test scenes resulted in some busy bokeh, but I've been shooting primes a lot lately, so possibly not a fair comparison. One thing I really have to get used to - that I have found surprising - is the silent motor makes it difficult to know if the lens has settled into focus position. Oddly, I feel a lack of confidence as I take the shot; not very rational, but real.

12-29-2016, 04:37 PM	#23
Canada_Rockies Loyal Site Supporter Join Date: Nov 2007 Location: Sparwood, BC, Canada Photos: Gallery \| Albums Posts: 12,385	I'm a follower of "Only buy a non-manufacture lens if the manufacturer does not cover the range" quoted in some rather old (not quite as old as I, but close) photo books. I have had the DA*16-50/2.8 since early 2008 or late 2007. The AF still works. Slowly. Sometimes I have to wake it up, the common problem with SDM lenses. The images from my copy are nothing short of stunning. The focal length range suits me to a T. Even with the K10, cropping 50mm to get "closer" works, and frankly, the focal length, handling WR and such fit me well enough that if the SDM fails, I'll just use it as a manual focus lens. It falls into the "f/8 and be there" category in all honesty. I only pixel peep when figuring how big I can go, so minor details don't bother me. Some downplay the weight of "good" lenses, and worry about how much you carry around. I am a 1940 model, and I commonly carry my backpack plus a Manfrotto 055 aluminum tripod and RH2 gimbal head around with me. Not counting my lunch and water bottle some find it "way too heavy!" for their taste. The extra few ounces of a 16-50/2.8 are insignificant.

12-29-2016, 04:37 PM	#24
caliscouser Site Supporter Join Date: Sep 2014 Location: SF Bay Area, CA Photos: Albums Posts: 1,037	.... and to throw a wild card into the mix.. the DA 20-40 LTD DC WR. It checks a lot of boxes: weather-sealed, DC motor, excellent build quality, compact, lightweight. Image quality is arguably the best of the bunch, saturated, contrasty, sharp edge-to-edge. Faster than the kit lens, but not quite as fast as some of the others. Okay the focal range is more limited, but you have to think of this lens as a 'normal' lens with wriggle room each side. Since you have the 55-300 anyway the long end may not be too much of a big deal. The wide-end, that could be a problem. If you need wide then you need wide.

12-29-2016, 04:38 PM	#25
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,445	On a related note I am trying to pick a lens for my step-dad for his Nikon. I was very surprised to read a lot of reviews suggesting the 17-70 f/2.8-4 was a far better lens than the 17-50 f/2.8 Sigma. The crux of this was that the 17-70 was far sharper. They also mentioned surer focusing but given the difference in wide open aperture over much of the range that's hard to evaluate. Does anyone here think the 17-70 Sigma is a better lens optically than the 17-50?

12-29-2016, 07:28 PM	#27
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,445	Originally posted by audiobomber That example with the double edges is atrocious. I have not seen anything remotely like that in a year of usage. CA performance has been exemplary. Generally Sigmas excel in controlling CA, even with their humbler lenses. I have to wonder whether your 17-50mm is defective. ---------- Post added 2016-12-29 at 21:23 ---------- DXOMark doesn't think so. The 17-50mm scores 30% higher in overall sharpness. https://www.dxomark.com/Lenses/Compare/Side-by-side/Sigma-17-50mm-F28-EX-DC-...6_914_1051_914 I wonder if the review I saw was talking about the old version of the 17-50?

12-29-2016, 08:54 PM	#28
Sandy Hancock Moderator Site Supporter Join Date: Feb 2012 Location: Adelaide Hills, South Australia Photos: Gallery \| Albums Posts: 11,275	Originally posted by UncleVanya On a related note I am trying to pick a lens for my step-dad for his Nikon. I was very surprised to read a lot of reviews suggesting the 17-70 f/2.8-4 was a far better lens than the 17-50 f/2.8 Sigma. The crux of this was that the 17-70 was far sharper. They also mentioned surer focusing but given the difference in wide open aperture over much of the range that's hard to evaluate. Does anyone here think the 17-70 Sigma is a better lens optically than the 17-50? No data, just anecdote and opinion I'm afraid. I'm also talking about older versions of the Sigmas to.... The Sigma 17-70/2.8-4.0 was one of the first lenses I got for my first DSLR (K10D) back in 2008. I was very happy with it, but I was nowhere near as fussy as I am now I replaced it a few years later for the 17-50/2.8, which I took on a trip to Argentina and used for my early live music work. Although it got the job done I was never entirely happy with its sharpness or fringing, so I compared it for a while against the DA*16-50. The images from the latter were consistently more pleasing despite the lens' well publicised flaws. Four years later I still have the Pentax, and am only now considering moving it on as the DFA24-70 on the K-1 has replaced it. Hope that's of some help.

12-29-2016, 10:05 PM	#30
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,445	Originally posted by audiobomber My first day with the Sigma 17-50mm was a year ago. If you can find any fringing or CA in these, let me know. I don't see any. New 17-50mm \| Flickr ---------- Post added 2016-12-29 at 23:49 ---------- Maybe the Sigma 18-50mm f2.8, which was a bad lens from anything I've read. No -it was the 17-50 vs the 17-70 contemporary. At the time the contemporary was new. Sadly sampling size was a single lens of each - so not great statistically. Sorry to divert the conversation. Nikon is a distraction in this thread, forgive me.