[Adam]

Our latest in-depth review takes a look at Sigma's most recent prosumer walkaround lens, the 17-70mm F2.8-4 DC Macro HSM "Contemporary". Here's a link to the review:

Sigma 17-70mm F2.8-4 Contemporary - Introduction - PentaxForums.com



Please let me know if you spot any typos before review officially goes live tomorrow

Convinced to get the lens?
Sigma 17-70mm f/2.8-4 DC Macro HSM Lens for Pentax 884109 B&H

Adam
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[superdavis]

Thanks a lot for such a good and nice review. I am considering this lens and have one question that I cannot find answer to: If 17 mm - F2.8 and 70 mm - F4, then at what mm focal lenght 2.8 starts to change. It is only 17 mm 2.8 or ...

Thanks in advance

[superdavis]

This is what I found on the net:

17-20mm @f/2.8
20-28mm @f/3.2
28-50mm @f/3.5
50-70mm @f/4.0

[seventysixersfan]

See this post for the aperture changes according to the Lenstip review:

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/227555-new-sig...ml#post2414633

[seventysixersfan]

"overall, we see this lens as the ultimate kit lens replacement for Pentax DSLR owners!"

That's a great endorsement! Seems like there are very few reasons for anyone to get the Pentax DA 17-70 instead of the Sigma.

Now as for whether it's worth me getting this lens when I already have a DA 18-135, hmm... lots of thinking to do on that. LBA!

[Slice Of Light]

Adam,


Those are nice pics of the lens on the K-50 body.... taken with a Nikon D800, what?, no spare Pentax cameras on hand? lol


Good review, since it's new and already at $500, good chance there will be a sale price in the not to distant future, Sigma lenses seem to be frequently on sale, I'll wait till then.

[yellowbrick]

Wonder how well this lens would work on my K-01? Could be a bit too front-heavy. But I very much like the image quality, fast aperture, and zoom range. Can't make up my mind between the new Sigma 17-70 and DA 18-135... could come down to weather I want the additional zoom range or not...

[marcm]

I don't know why, but I had a different experience than most others here with the sigma 17-70 contemporary. First I tested it for sharpness against my 18-55 WR kit lens by shooting a test sheet/chart with each lens (using a K-30). The sigma contemporary was sharper, noticeably sharper, but not by leaps and bounds. I then shot photos around the neighborhood, the same scenes with both lenses. I was surprised to see that the kit lens was consistently sharper than the sigma! I don't have an explanation (my shots were compared at the same f stops and shutter speeds). I was also surprised to observe that the color on the sigma was much duller than the color on the kit lens. The kit lens can sometimes take colors that are a little too color saturated, but I felt the kit lens did a better job with both sharpness and color with my neighborhood photos. Given that the kit lens definitely has the advantage when it comes to price and weight/size, I sent the lens back. I know the sigma has the advantage of having more focal length on the wide angle and telephoto ends of the spectrum and that the sigma lets about twice the light into the camera as kit lens. I also know that many who prefer the sigma over the kit lens know much more about lens than I do and have more educated eyes, so I make no claim that the kit lens is the better lens (I suspect it isn't). I saw wonderful photos from the sigma online. Mine were not wonderful. However, I thought it best to report my true experience.

[tibbitts]

I don't know why, but I had a different experience than most others here with the sigma 17-70 contemporary. First I tested it for sharpness against my 18-55 WR kit lens by shooting a test sheet/chart with each lens (using a K-30). The sigma contemporary was sharper, noticeably sharper, but not by leaps and bounds. I then shot photos around the neighborhood, the same scenes with both lenses. I was surprised to see that the kit lens was consistently sharper than the sigma! I don't have an explanation (my shots were compared at the same f stops and shutter speeds). I was also surprised to observe that the color on the sigma was much duller than the color on the kit lens. The kit lens can sometimes take colors that are a little too color saturated, but I felt the kit lens did a better job with both sharpness and color with my neighborhood photos. Given that the kit lens definitely has the advantage when it comes to price and weight/size, I sent the lens back. I know the sigma has the advantage of having more focal length on the wide angle and telephoto ends of the spectrum and that the sigma lets about twice the light into the camera as kit lens. I also know that many who prefer the sigma over the kit lens know much more about lens than I do and have more educated eyes, so I make no claim that the kit lens is the better lens (I suspect it isn't). I saw wonderful photos from the sigma online. Mine were not wonderful. However, I thought it best to report my true experience.

Comparing lenses can be difficult, particularly with zooms, because there are so many combinations (focal length, distances, apertures) that need to be tested. It might be - and is probably likely - that other copies of the lenses, possibly on a different bodies, would have produced different results. But that's no reason to dismiss your results, and it's helpful to others to be aware that there is at least the possibility the the sigma won't outperform the kit lens (although the sigma is certainly more versatile.)

[reeftool]

My main reason for buying the Sigma was the added range. The 18-55 is a decent lens and still continues to surprise me. I got it mostly to replace a 35-70 which broke. After a few years of shooting, I came to the conclusion that the 17-70 focal length was a good size for my use. In all honesty, if I didn't buy the Sigma, I probably would have picked up the DA 18-135. So far, I have no complaints about the IQ. My youngest daughter was married this weekend and the Sigma got a good workout. I'm going through the shots and so far see nothing that leads me to believe that this lens is of lesser quality than the 18-55 kit. I did a lot of shooting in difficult light and the AF performed well. Being faster is always a benefit and my f/2.8 shots look pretty good. I haven't used it enough yet to form a final opinion.

I should add that I have several primes that cover the focal range including 2 Limiteds. This lens is not a replacement for them but mostly a convenience tool and it's a little more versatile than the 18-55 which I'm keeping also.

[marcm]

I think tibbits is correct in that there are many variables in comparing zoom lens. It could be my copy of the kit lens is better than average and the sigma 17-70 was less than average. Or that I did my comparisons wrong. I am glad that reeftool and others have found their sigma 17-70s optically superior to the 18-55mm WR kit lens. The sigma 17-70 is certainly more versatile and I believe it usually outperforms optically the kit lens. I would have kept it if I experienced what most others had experienced. I have attached two photos to compare my results with the two lenses. The photo with a little bit of fence in it on the right was taken with the 17-70 and the other photo with the kit lens. Here one can see kit lens is sharper (look at the top right hand corner) and has more pleasing colors (contrast?).

Could some of the difference be that the k-30 knows how to identify and self-possess jpgs from the kit lens, but it can't do (and won't do) the same for sigma lens?

[reeftool]

While "optically superior" isn't a term I would use, for my uses, the Sigma is is a little more useful with it's slightly faster aperture range and longer reach. If that $399 deal on the DA18-135 was available 3 weeks ago, that lens would be in my bag as the Sigma was almost $100 cheaper. I haven't shot a single JPEG with the SIgma so I can't comment much as regards to how the camera would process them differently. All of my shots have been in difficult light too which is not the ideal platform to compare lenses. I did take advantage of the Sigma's f/2.8 on the wide end at the wedding reception. That did have some influence on my purchase as all my primes that are f/2.8 and faster are 28mm and larger. Actually, my favorite photos so far from inside the dark pub where the reception was held came not from my K5 and any of my lenses but from my Lumix LF1 with it's f/2 Leica zoom. I was firing off some one handed snapshots at the dinner table and the results were stunning.

[tibbitts]

Although the two test images are difficult to compare due to the differences in the framing, assuming the aperture, etc. were the same and that the upper right is weaker than the other corners, that would tend to indicate a lens defect. Sigma claims to have implemented additional resolution testing in the manufacture of its new lenses, so assuming that applies to this model, that doesn't speak well for that process.

[reeftool]

The upper right is also soft on the 18-55 shot but the tree branches are much denser and that part of the frame is darker in the first shot and it isn't as noticeable. To really do a test right, the camera should have been tripod mounted and the scene should have been the exact same framing with each lens and from the same distance from the subject. These shots really tell us nothing. They were shot from different distances and the light was not the same, Differences in contrast are to be expected as can a slight difference in exposure as the light transmission will not be exactly the same. You might even find these differences in different copies of the same lens. That stuff is easily corrected in PP.

Of course, the OP was certainly within his rights to send the lens back if he wasn't happy with it. As I said, I'm quite happy with my 18-55, it's just not as convenient a walk around length for my uses.

Here are some of my shots from my only (so far) use of the 17-70 at my daughters wedding. I am NOT a wedding photographer and totally out of my comfort zone doing this.

The ceremony was in this room at the Canfield Casino in Saratoga Springs, NY. I came prepared to shoot outside but the snow wasn't cleared out of the gazebo in the park we were supposed to use. Blinding light coming in from a window and I had to squat low to keep all the people behind me out of the mirror. I bounced flash off the ceiling to light the couple. 3 different white balances in this room.


Getting away from those windows, the flash worked much better.


Then it was outside in the snow.


Then to a local pub for the reception. We has the upstairs section. Strange colored lights and more #$@#$ windows!


The lens worked quite well in the 24-28mm range and mostly wide open. This was at 26mm and f/3.5


So far, I'm happy with the lens. The final album will probably have many of my oldest daughters shots as she does quite a bit of event photography. She's a Nikon shooter and I haven't been able to convert her yet.

[MadMathMind]

This is what I found on the net:

17-20mm @f/2.8
20-28mm @f/3.2
28-50mm @f/3.5
50-70mm @f/4.0

This is not correct, btw. There's no 3.2 minimum anywhere. The correct ranges are:

f/2.8: 17-21mm
f/3.5: 22-45mm
f/4.0: 46-70mm