9 out of 10 points and recommendedBuild quality, ultrawide, sharp, great CA control.Fat (doesn't fit in any of my lens cases), 77mm filters expensive, nothing to speak of really.
This is my third Sigma lens, and by far the newest model I own. I am continually impressed with the Sigma design and build quality, and more importantly the value.reviewed December 20th, 2006 (purchased for $485)
This lens is fat, and a little on the hefty side. 77mm filters will be expensive. It feels very solid, and the zoom and focus rings are smooth and well damped. In fact, these are the best feeling rings I have felt on a modern lens (kind of reminds me of my old manual focus Rokkor days). It comes with a zippered case with belt loop, a very nice bayonet mount pedal hood, and back and front caps (although Sigma's non pinch style lens cap is almost impossible to remove and re-attach when the hood is on).
The HSM focusing is practically silent and very fast... the focus ring does not turn during auto-focus, and of course you have the option to grab hold of it and manually focus anytime you feel like it. The manual focus ring has no actual stops, but you can instantly feel when you have reached infinity or the near focus point. It would have been nice to see DOF marks on the focus index as well as a few more incremental markings (none between 3 feet and infinity), but other than this and the lens cap (which I will replace with a Nikon one), I could not be more pleased with the feel, fit, finish, and operation of this lens.
I really like the focal length range of this lens. It was hard to visualize as I bought it sight unseen, and the closest thing I have owned to compare it to was the Nikon 10.5mm Fisheye. At 10mm, the FOV is amazing!
One of the reasons I was less than thrilled with the Nikon 10.5mm was that it was not all that sharp at the edges/corners (I even sent it to Nikon to be sure there was not an issue with it). The edge to edge sharpness is very good with the Sigma. I have seen many discussions of samples of this lens not being consistently sharp from edge to edge. Doesn't seem to be an issue here.
I shot some high contrast back lit scenes to test for CA. The Nikon 10.5 was particularly poor at this, especially at the sides and corners. The Sigma seems to be incredibly well controlled, especially for such extreme focal lengths. There is some noticeable light fall off in the corners when approaching 20mm but that is easily fixed in post.
I did encounter a bit of flair in some shots (like sun peeking through trees) but these were pretty extreme situations that would affect most lenses.
8 out of 10 points and recommendedHard to do better than this optically.Extremely long focus range makes for slow focusing, focus clutch a bit clumsy.
Optically... you would be hard pressed to do better than this lens at any price. It is fast, tack sharp, and just probably the best lens I have put on either my digital or film bodies. Couple that with its $400 street price, excellent build quality, and a 4 year warranty and you have a tremendous value in both a fast tele prime and 1:1 macro with excellent working distance.reviewed December 22nd, 2006 (purchased for $420)
It is not without its faults as the focus ring clutch is a little clumsy and I am still trying to get used to Sigma's EX finish, but it is a top notch performer.
That's it as I simply have nothing bad to say about this lens. Yes HSM would be an improvement, but you could spend significantly more and not get the optical quality that this lens offers!
8 out of 10 points and recommendedSharp, long, and inexpensive.Lens creeps quite easily and is a bit clumsey.
This lens is an older design, recently updated with Sigma's DG coatings for better flare/reflection control for DSLRs. When researching to see if this lens was right for me, I read many comments about it being soft and slow to focus... but I had seen far too many photos taken with it that would indicate that this was not the case.reviewed December 29th, 2006 (purchased for $679)
Before purchasing, I had the opportunity to shoot this lens along with the Sigma 50-500 and 80-400 OS, the Nikon 80-400 VR and 300 AF-S f/4, and the Tokina 80-400. I saw no significant difference between the Sigma and Nikon zooms. Yes the OS/VR models are a big advantage for hand held shots, but no match for a good tripod. And I felt it was sharper with better color rendition than the Tokina. However the 300mm Nikon prime was noticeably better in all respects, especially it's amazing resolution and CA control. But back to the lens at hand.
If your looking for a big tele-zoom and have the up to 200mm range covered with other glass this lens is an excellent value. If you don't, you may wish to consider the $300+ pricer 50-500mm or the OS/VR models. My biggest complaint of the 170-500mm is it creeps easily when pointed straight up or down, and really would be easier to carry/handle with a focal length lock.
As far as sharpness is concerned, this lens is as capable of sharp shots as the other tele-zooms, but keep in mind this pup is the equivalent of 750mm FOV on APS-C sensors and your tripod and head/mount better be up to it. Mine wasn't, and camera movement induced by mirror slap made for unsharp shots at 500mm. This was far less noticeable on my film body so it is that extra 250mm that is really going to test your support system. At high shutter speeds (1/750th and up) this is not such an issue.
The supplied tripod collar is well designed and very solid... oddly enough better than that of the much pricier Nikons mentioned above.
In good light autofocus is as good as any screw drive lens, but it can definitely hunt in low light. If you have enough light to hand hold this lens, focus speed will not be much of an issue.
At best this lens is a compromise. If your looking to go walking about you will do well to consider one of the 80-400 OS/VR offerings as the 170-500 is a bit clumsy and will need the brightest of light for hand held shots. However if you want as much reach as possible from a good tripod its bang for the buck is hard to ignore.
8 out of 10 points and recommendedSmall, light weight, and sharp.none in this price/zoom range class.
I love this lens, and find it on my D50 most of the time. I have yet to use it much on my F75 so I can not speak to the vignetting and pin cushion issues others have mentioned, but it performs well indeed on the D50.reviewed December 29th, 2006 (purchased for $315)
While not a real macro it focuses quite close, and is an excellent close up lens.
As for the plastic mount... you'll be fine as long as you're not planning on dropping it.
This lens has taken some remarkable images at many different focal lengths, and of the do all zooms, is as good or better than most. It is a shame it has been discontinued but I am guessing all the hoopla about the pricier 18-200vr has stolen much of its thunder. You'll be hard pressed to do better than this for three hundred bucks.
7 out of 10 points and recommendedLarge zoom range, VRPricey, not all that sharp, questionable build quality at its price, mediocre CA control
After all I have read of this lens I really thought it would be something special... it's not. I wasn't planning a review of this lens as I returned mine, but I thought a reality check might be in order for those contemplating this as I did, due to all the glowing press.reviewed December 29th, 2006 (purchased for $799)
Yes it has the kind of zoom range where it could be the only lens you use, and it is good throughout its focal range, but it is far from great optically. I see a lot of "tens" here and am wondering what they could possibly be comparing it to to justify a perfect score. I find my 28-200G to be sharper and have better CA control, and my 50mm and 105mm primes blew it away.
Although this is a good "all in one" lens, it is not without compromises, especially at this price point. Many will do better to cover this lens' focal range with several other zooms/primes if optical quality is paramount. To me this is the main advantage of having a SLR.
But with that said, this lens is a major achievement for those that just don't want to be bothered swapping glass and/or lugging a tripod, and is capable of good results under a wide variety of conditions.
And while I found the VR to work well, I am afraid it did not offer me much else so I saw little reason to keep it.