Sigma 17-70mm f/2.8-4.5 DC Macro
(From Sigma lens literature) Sigma Corporation is pleased to announce the launch of the new 17-70mm f/2.8-4.5 DC Macro lens. It can be used with wide variety of subjects and it is an ideal large aperture standard zoom lens for digital SLR cameras featuring an APS-C size image sensor.
This lens has a minimum focusing distance of 20cm (7.9") throughout the entire zoom range. Maximum magnification of 1:2.3 enables close-up photography like a macro lens. The new lens design and multi layer lens coating reduce flare and ghosting, which is a common problem with digital cameras. A Special Low Dispersion (SLD) lens and two aspherical lens elements provide excellent correction for all types of aberrations and produce a high level of optical performance throughout the entire zoom range.
This lens offers a large aperture of f/2.8 at 17mm wide angle and yet it is compact, with an overall length of 82.5mm (3.2") and diameter of 79mm (3.1"). It performs superbly even in relatively low light conditions indoors or at dusk.
The lens design incorporates an inner focusing system, which ensures fast AF speed as well as prevents the front of the lens rotating, making it particularly suitable for use with circular polarizing filters and petal shaped lens hoods. This lens is also equipped with Zoom Lock Switch that eliminates "Zoom Creep" during transportation.
Note: Sigma has announced an HSM (Hyper-Sonic Motor) version of this lens for Nikon mount (which supports autofocus with D40 and D40x, as well as other Nikon DSLRs).
Sigma is a lens manufacturer that's really getting behind the sub-frame DSLR market, rolling out a number of lenses with reduced image circles (and reduced bulk and weight to match) designed specifically for use with sub-frame DSLRs. This 17-70mm f/2.8-4.5 DC Macro is one such, offering a lot of optical capability in a small package. (The DC in the name indicates that it's a Digital lens, intended for use on cameras with sub-frame sensors.) This particular lens competes strongly with the "kit" lenses offered by most camera makers, and may make a good alternative to the kit optics for new DSLR purchasers.
Sigma's lenses are generally known for their sharpness, and the 17-70mm DC follows that tradition. It's very sharp in the center across its focal length range, but the corners do get slightly soft when shooting wide open at both ends of its focal length range. Where the Sigma 17-70mm really shines though, is when you stop it down a little: One stop down from wide open, the corners get much sharper, and two stops down it's tack sharp across the entire frame, and across the full focal length range.
Other characteristics are also good. Chromatic aberration is very low at middle focal lengths, rising slightly at maximum wide angle and telephoto. Geometric distortion is very typical for a lens of this class and focal length range, varying from about 1% barrel at 17mm to about 0.2% pincushion at 70mm. The zero-distortion point occurs right around 30mm. Light falloff ("vignetting") is also pretty typical, reaching a maximum of 0.67 EV wide open at 17mm, but dropping to 0.34 EV at f/4, and 0.25 EV at f/5.6. From 25-70mm though, the maximum falloff is never more than 1/4 EV.
One claim to fame of this lens is its macro capability. The closest-focus spec of 20cm translated to a distance from the front element of only a coupleof inches or so on our Canon EOS-20D body, very close focusing indeed. (Thanks to reader Alistair Windsor for pointing out my error in interpreting the focal distance spec. As is always the case with SLR lenses, the focusing distance spec is referenced to the film/sensor plane, not the front element of the lens itself.)
Build-wise, the Sigma 17-70mm is quite satisfying, it has a nice solid feel, probably better than average for lenses in its price bracket, and the zoom setting on our test sample showed no tendency to creep when the lens was held pointing up or down. The manual focusing ring worked well also, with enough travel that setting focus manually was pretty easy. When autofocusing, the lens is a bit noisy, but not as bad as some we've seen. Overall, a lens that feels good and works well.
Sigma 17-70mm vs Canon 18-55mm kit lens
Compared to Canon's 18-55mm kit lens, this Sigma has wider apertures across its focal length range, and gives you a fair bit more at the telephoto end. It's also much better on chromatic aberration at all focal lengths. All in all, a worthy upgrade over the Canon 18-55, to the point that many purchasers of Canon's entry-level DSLRs may want to consider getting a bare body and then purchasing this lens separately.
Sigma 17-70mm vs Nikon 18-70mm kit lens
Turning to the Nikon camp, the Sigma 17-70 is perhaps less of a slam-dunk relative to Nikon's very good 18-70mm kit lens, but does still show some clear advantages. The Sigma gives you just a bit more aperture at the wide angle end, but as noted in one of the user reviews below, that advantage doesn't extend across much of the zoom range. Chromatic aberration is a close call between the two lenses, the Nikon winning in some areas, the Sigma in others. The Sigma 17-70mm does have one strong advantage over the Nikon 18-70 though, and that's macro focusing ability. Minimum focus with the Nikon is 38cm, while the Sigma can get in to just 20cm. The Sigma also wins on center sharpness across much of its range, but corners get slightly soft wide open at either end of the focal length range. Stopped down to f/5.6 though, it's noticeably sharper at all zoom positions. All in all, not a bad option, even against Nikon's very good kit lens, particularly if you'd like at least modest macro capability.
Other kit lenses?
We suspect that the Sigma 17-70mm would do well against the manufacturer's kit lenses for other platforms it's available on (Pentax and Sony/Konica Minolta), but can't make direct comparisons since we haven't tested the kit lenses made by those manufacturers.
Overall, the Sigma 17-70mm f/2.8-4.5 DC Macro looks like a great, all-around lens, one that you could leave attached to your DSLR most of the time, and one that beats most manufacturers' kit lenses in sharpness and (particularly) macro capability.
Sigma 17-70mm f/2.8-4.5 DC Macro User Reviews
7 out of 10 points and recommended by kiwijono (6 reviews)Great range, Good IQ, Faster than 18-55 kit lens, Good valueQuality (focus) issues
I bought this lens while on holiday in Australia and after getting back to NZ, I was disappointed with the results. A large number of images were blurry and not sharp. Focus tests showed up a lot of back focus (and sometimes even front focus) at different focal lengths. I sent the lens back to the NZ support agent (who, to their credit, honored the "Australia Only" warranty). It ended up away for 4 weeks, leaving me stewing about it!reviewed March 14th, 2014 (purchased for $295)
If this was the end of the story then the rating would be maybe a 2, however...
Upon getting it back (apparently after recalibrating the autofocus) I immediately noticed a big difference in performance. I now had a very usable, flexible lens that rendered nice colors! Sure at some focal lengths it is still less sharp than others (around 50mm is not its strong point) but never less than acceptable for a zoom IMO. My copy is actually quite sharp at 70mm which is a focal length I use quite a lot. I also use it a lot at the other end (around 20mm) which is also very good.
Having f2.8 available (even if only at wide end) is really quite useful and has allowed me to capture shots that I think would have been more of a struggle with only f4 available.
I also have the Pentax 18-55 kit lens and in comparison the Sigma has:
* Similar centre sharpness
* Somewhat better on average across frame
* Faster across the range (useful)
* Much better focal range (for me anyway - far less lens swaps)
Without the initial quality issues I would have rated it a 8 based on value for money. However factoring in the initial issues I have settled on a 7. Perhaps it should have averaged lower but the bottom line is I like it
I have since got a Pentax 18-135 and find the new Pentax is better all round and has WR. Since then my 17-70 is no longer used.
9 out of 10 points and recommended by zpuskas (1 reviews)price, focal range, maximum aperturenone for the price
Bought this used as my first APS-C lens coming from Micro 4/3. Read the reviews and made the selection based on the reviews. I'm not disappointed. Not noisy, sharp (not super) but certainly very good.reviewed August 17th, 2013 (purchased for $345)
8 out of 10 points and recommended by kaci (10 reviews)sharpness, focal length range, macroCA, colours a little bit
Great lens for those who wants generall purpose zoom for APS-C camera and don´t want to spend a lot of money. Reasonable sharp, macro is fine. Colours are little bit yelowish and not so bright, contrast average. AF is precise.reviewed April 15th, 2011 (purchased for $420)
Buy this lens and 35 or 50 prime and you will be satisfied.
10 out of 10 points and recommended by cmm895 (6 reviews)macro ability, price, image qualitynot f2.8 through the zoom range, uses expensive 72mm filters, no IS
I bought this lens as a walkaround capable of taking shots of scenery and also for use with macro. It has lived up to my expectations. I use it on a canon eos 450d. The macro ability might not be as good as a prime macro lens but it is also cheaper and can be used to do landscapes. I have used this lens for portraits but its not a fast lens so the results dont have much bokeh. I notice that Sigma have just bought out a new optical stabilised version which will improve this fantastic lens.reviewed July 4th, 2010 (purchased for $350)
8 out of 10 points and recommended by manieknww (1 reviews)price, focal range, max apertures, surprisinlgy sharp at F2.8, lightslow and loud focusing
Great replacement lens for a kit, focal range makes you keep it on in most of situations and max apertures allow some portrait photorgaphy.reviewed November 22nd, 2009 (purchased for $363)
IQ deteriorates with zooming in so lens requires stopping down on long end. But at wide end even F2.8 is decently sharp.
For me the biggest issue with this lens was slow AF. It's a shame Sigma hasn't released this for Canon with HSM as it did with Nikon model...
10 out of 10 points and recommended by Tommygun (4 reviews)Fantastic value lens, very sharp, great build with very close focus abilityNone at the price
Fantastic lens for portraits, good build and range. A great lens for the money. Better than any kit lens from Canon or Nikon.reviewed June 20th, 2009
8 out of 10 points and recommended by climber (11 reviews)great zoom range, built quality, very good image quality, price/performancenone for this price
Great walk arround lens with very good image quality and price/performance. 70mm is very usefull comperable to standard 17-50 zooms.reviewed April 22nd, 2009 (purchased for $400)
It's a very nice beginner lens.
8 out of 10 points and recommended by photographybyajit (4 reviews)Excellent starter Lens; Price; Construction Quality; Above average image qualityNoisy Focusing, no HSM;
This was my first lens about 2 years back for my Canon XTi, but I only used it for a year and sold it off for a further upgrade. Although a very good starter lens for someone on a tight budget, but even a serious hobbyist won’t hold on to it for very long.reviewed February 1st, 2009 (purchased for $425)
Overall the image quality is reasonably good with very sharp in the center to getting softer as you move away from the center. Well built with focal range offering a wide variety of photographic capabilities.
Macro results are ok, but frankly speaking, nothing beats primes in macro photography.
Since this model did not support HSM (Hyper-Sonic Motor), the focusing is quite noisy with sudden movements in the focusing ring outside. You need to be sure your fingers are not on top of the ring. I’ve heard Sigma has now recently launched an HSM version of this lens.
Would like to share some shots with my Sigma 17-70mm f2.8-4.5 on my Canon XTi:
9 out of 10 points and recommended by NLxAROSA (2 reviews)Price, sharpness, fast AFProne to lens flare, 2.8 only available while zoomed out, bokeh
Excellent lens for the price. The sharpness is very good wide open and becomes excellent when stopped down a bit. I have experienced no CA, even in high-contrast situations. Bokeh is not the strongest point of this lens. It's also prone to flare, which ofcourse can be solved with a lens hood (comes with the lens, so no extra costs there). It's also very solidly built.reviewed January 29th, 2009 (purchased for $350)
4 out of 10 points and not recommended by griggsjiml (1 reviews)small - light - fast to use in the correct lightfocus issues in backlit subjects and low light
I have had numerous problems with focus on this lens. It seems to just give up once it gets close and says, "Good Enough". I use it for portrait and wedding work and about 15% of the time in backlit settings which I use a lot in portrait work it is soft to the point of not being usable. I am getting ready to sell it to someone who will use it for outdoor landscape type stuff in good lighting. Replaced it with a Canon 24-105L IS. My friend George Lepp told me I would not be happy with this lens and he was correct. I e-mailed him and said, "you win; I bought the Canon 24-105." This is a good lens for certain subjects but I would not recommend it for weddings and portrait work. When it is sharp, the images are very sharp indeed but when it is soft they are terrible.reviewed December 11th, 2008 (purchased for $440)
10 out of 10 points and recommended by upnorthfar (3 reviews)zoom range, sharpness, macro
I gave this lens a 10 on image quality. Simply because at 300,- the image quality is unbeatable by any Canon offerings. If you use this lens from f/5.6 it's very sharp. Also the tele end. I've been eyeballing Canon lenses for long but come to the conclusion over and over again that I will be loosing too much tele end and macro to make up for any slight image quality improvement a 17-40 or 17-55IS could give. And others are behind in IQ. I use it mostly 17-35mm and 70mm, so loosing the 70mm would be a big set back.reviewed October 1st, 2008 (purchased for $300)
Check the stopped down test results here and compare to other lenses, this one is a gem.
9 out of 10 points and recommended by bdery (6 reviews)Image quality, build quality, priceNone significant for this price
I am using this lens on a Pentax K20D. The build quality is impressive, the finish feels high-quality and solid. The zoom ring oerates very smoothly, but the focus ring is very lifeless and has a short throw. Autofocus is very fast, the only times the lens unted was at telephoto uder the stars with no light source. In that case, simply zoom back to get a wider aperture, focus, lock focus and zoom in again.reviewed July 7th, 2008 (purchased for $420)
Image quality is impressive. There can be visible barrel distorsion at 17 mm if you shoot flat and linear targets (like a waterline, or a building) but zooming in a little bit takes care of it. I haven't searched for, and have neveer noticed, any chromatic aberation (it's there somewhere for sure, but if I cannot notice it, then it doesn't bother me).
Macro is great, focus is accurate,reliable, and the lens produces very sharp images.
My lens has no zoom creep, and feels like it will last me years.
This is m first personally owned autofocus lens (my others are manual) bt I can compare with various kit lenses and even pro models from Pentax, and in handling and focusing it compares with the best, and regarding build quality it's above most kit lenses out there.
9 out of 10 points and recommended by grim grimsson (6 reviews)useful focal lenghtslow
17 - 70 mm is a very useful focal range. Compared to other normal zoom lenses you gain extra range. It is not as fast as the best 18-50 or 28-70 lenses, actually f2.8 is available only when zoomed out. I purchased this lens a year ago instead of 18-50mm/28-70mm because I wanted the extra range, and I would have done the same todayreviewed June 30th, 2008 (purchased for $500)
A bit soft wide open, you don't need to stop down much for it to be reasonably sharp.
Build quality is very good.
9 out of 10 points and recommended by jamesm007 (7 reviews)solid build quality, great focal range, very good IQ through the whole range, low costIQ at 17mm in the very corners a tad soft wide open, could be faster at the longer focal lenghts
I will be as honest as possible to help others in thier decision, but this is for my copy, and copies can vary. On my Samsung GX10 this lens is quite a bit more heavy than the stock lens, although this weight is because of the high build quality, and it does balance nicely on the GX10. The focal range is great and the little extra on both ends is noticable and very useful, compared to 18-55mm lens. The zoom action is smooth and my copy has no creep even shaken lightly upside down. The focus ring is nice, it could be a bit more resistant but its fine. The image quality is very good at 17mm and f2.8 only the deep corners are soft, but most of the frame is good, stopped down just a little and things get better, it peaks at f/5.6-8 and is excellent with great contrast, color and sharpness. You will see the difference over the kit. This quality carries through all of the range. AT 70mm it gets a tad soft in the corners again wide open and it helps to stop it down, peak sharpness is about f8. So it could be a bit faster on that end but its not bad. This lens also has great macro ability and can focus on things almost touching or even touching the front glass element. Bokeh is not bad but not the best, its good and dependent on settings. CA/PF is well controlled as it seems with all Sigma lens, it's there a little, especially at the wide end, but never a problem; I dont need to remove it with PP, becuase its not visiable so far at least. Distortion is fair at 17mm and it has a bit of barrel distortion that I remove with PTlens. Overall thier is no real bad things that this lens does, anything it does not do well is typical with others in its class (average), but its better than average in most areas and that's what makes it a real winner for a walk around lens at its price range. Pentax has just announced thier DA-17-70 f4 lens, it will be interesting to see how it compares. But as it stands now this lens offers great color and contrast, is very sharp and has a great range. The f2.8 at 17mm is usable and it never needs to be down (if your DOF is OK), or has any bad spots to avoid, the whole focal range can be used. CA/PF is never a problem and this lens is just great I have no desire to replace it with any lens offered today as my walk around lens.reviewed June 23rd, 2008 (purchased for $370)
Now 7 years latter and 4 bodies latter (2 Samsung GX10, Pentax K20D, Pentax k-5) this lens is still as stated above. The lens is really sharp on the K20D and going to the K-5 was no problem for it. Its still a lens I don't want to replace. The Pentax DA17-70mm f/4 although good, won't make me sell my Sigma lens and buy it. Now 2015 and Pentax has a DA16-85mm f/3.5-5.6 again Pentax has me interested. It has weather sealing, a AF motor. Wider range. Is it worth it? Yes/No, if you don't have a walk around take a look at it. But for me the Sigma has earned a permanent home along with the K20D for the hard work and superb pics they produced. This is a simple lens that works well. And this model is no longer in production.
8 out of 10 points and recommended by Don Gould (2 reviews)Good zoom range for general purpose lenslong barrel extension
Recently purchased this lens to use on Pentax K1ooD super. I am only an amateur and have little understanding used in test notes. However I have been happy with the lens. Image seems to be fairly sharp which is my main requirement. Build quality is reasonably good for the price. Barrel extends a long way but presumably this has to be. I have not experienced any "zoom creep".reviewed May 4th, 2008 (purchased for $275)
9 out of 10 points and recommended by jmhesel (1 reviews)Nice balance - my example is sharp - excellent warrantyWould hsve paid more for EX & f2.8 accross the zoom range
I bought new in January with a D300 & companion Sigma 10-20 EX & Nikkor 70-300 VR. I am very happy - find no specific faults or concerns and recently did a pano shot for a 3 panel print on canvas at 20" X 72" - sharp & detailed (the D300 helped!!). I've been hesitant about Sigma, but bought anyway as much for feel & price. The results have proven Sigma can be a good choice.reviewed April 11th, 2008 (purchased for $389)
9 out of 10 points and recommended by Barbu (2 reviews)Tack sharp, extended focal rangeFocusing a bit loud
I have this lens for a year, and meanwhile I got to make an informed opinion about it.reviewed April 3rd, 2008 (purchased for $600)
I've seen the other posts and I don't know what to make of them; regarding image quality, it's the best "normal zoom" lens. Extremely sharp even for macro photography, and even when using 25mm macro rings.
Sharpness: excelent, my copy is as sharp as Canon's 17-55IS and vastly superior to the Canon's 17-85IS; wide-open is amazing, and if it was made by Canon it'd get an L designation.
Chromatic aberation: extremely low, under one pixel even in corners.
Flare: very resistant, and the included lens shade makes short work of it.
Contrast, color: perfect. I used it for three weddings (coupled with a Canon 30D) and half of the time was used wide-open, for "available darkness" photography; the shadows held up with lots of detail, and colors were accurate indoor and outdoor.
A friend of mine aquired a good copy after turning down another two, but I got mine as the last one from the shelf (so I couldn't afford the luxury of hand-picking between copies); nevertheless, I ended up with a perfect one.
Regarding the batch variance, I don't know what to think; people seem to have various opinion, but a certain regard could not change: bokeh. Contrary to some other views, my Sigma produces butter-smooth background both wide-open and when stopped down to f/6.3-f/11; this is part of the design, and a requirement for portrait and macro.
The only gripe that I have is that the focus is loud; on the other hand, focusing is done quickly in all but the darkest environments.
Overall, I recommend it wholeheartedly; it's head and shoulders above any kit lens (18-70 Nikkor, 18-55IS), and it has a very useful focal range while being satisfactory luminous.
P.S.: the price was a bit high, but that's because in Europe everybody pays a price premium.
6 out of 10 points and not recommended by morrisseysb1 (2 reviews)Zoom rangeSharpness....auto focus not accurate, zoom ring does not stay tight
I had two coppies of this lens. One was a grey market copy which I was told was a US version when I bought it. I returned that one and got a legit copy. Needless to say the auto focus was horrible on both coppies I had. The range is good on this lens...but I could never get a nice sharp picture out of it from my XTi. I returned it and got a Tamron 17-50 2.8...not quite the same range...but so far IQ and auto focus alone are worth the tradeoff.reviewed March 22nd, 2008 (purchased for $360)
8 out of 10 points and recommended by mrmr (6 reviews)Excellent all rounder, travel or "only" lens.Truly terrible bokeh - don't even think about portrait work.
I love this lens .. and I hate it, in pretty equal measure...reviewed June 13th, 2007 (purchased for $350)
It gives me a sharp, clear, all round useful lens in almost all circumstances, with the ability to do pseudo macro work thrown in for free (the kind of shots you can get with a 20cm focus distance and 17mm focal length are pretty rare for an SLR lens).
It doesn't flare much (though it's not as good as the Canon 17-40L for example), and it's usable wide open at all focal lengths (though arguably a little soft) - the point is it doesn't fall apart like many lenses do, or lose masses of contrast - even that f2.8 at 17mm is usable if you're not looking to produce great artworks or have fine detail in the corners of your image.
It produces consistently sharp, contrasty images, and is well built - it feels solid and weighty. The focus is quick and quiet (as long as you don't want it to do full-sweep), and pretty accurate. But that's less of a problem on this lens - it appears to have a pretty flat field even at 17mm.
The downsides, however, show up when you start to look more closely...
CA is pretty rough at 17mm, particularly wide open, but hey shoot raw and that'll be fixed for you. It's not much worse than many other lenses at 17mm.
Geometry distortion: average - lots of barrel at 17mm, but not too bad.
But the big killer for many shots is bokeh .. it's bad.. If your background is evenly lit and has no highlights you'll likely get away with it, but out-of-focus specular highlights will be rendered as a noticeable bright outer ring with a point in the centre aswell.. Not pleasant. Don't even think of blades of grass, you'll be seeing double..
For the money, it's a killer lens. For the money, it's an excellent upgrade from the kit lenses available (particularly as there's really no direct competition on a canon dslr). But you get what you pay for, so it has it's drawbacks.
10 out of 10 points and recommended by urxtream (1 reviews)Very sharp lens, macro capabilitiesVignetting
Absolutely love this lens. It was an upgrade from the kit lens which in my opinion was lacking a bit in performance.reviewed June 9th, 2007 (purchased for $310)
5 out of 10 points and not recommended by SETI (20 reviews)Size, Macro capabilityToo hard images ! Macro images are too flat and expressionless
I got that lens after reading so much positive reviews in our magazines. I was greatly disappointed because of harsh pictures. Avoid to shoot mid-aged women with that lens =) All skin deffects will be visible twice strong !reviewed April 26th, 2007 (purchased for $400)
Sold it with a great pleasure.
Thank you !
8 out of 10 points and recommended by blue_streak (2 reviews)Sharp Images, Price, Size, WeightVingetting at wide angle
I bought this lens as replacement to the 18-55 kit lens sold with the 30D. It is certainly an improvement. This lens does offer a wide angle at 17mm, but I have found that the image quality is improved at 17mm if I step the aperture to f/4.0, the “sweet spot” of the lens if you will. The lens has some vingetting problems at 17mm f/2.8. This makes me question why I bought a lens with a 2.8 aperture capability that I will no longer use.reviewed January 29th, 2007 (purchased for $380)
I must say that when I am outdoors with this lens it takes some wonderfully sharp pictures that I am happy with.
I have been considering an upgrade to an L series Canon lens (falling into the same dilemma as many) whether to purchase the 24-70 f/2.8 or the 24-105 f/4.0 and then maybe a wide angle down the road. The lens was good for me as a beginner, but I am not completely satisfied……and I know it will cost me!
If you want a sharp lens and you are on a budget, this might be the ticket, however, I feel like the lens has kept my 30D’s potential somewhat captive.
9 out of 10 points and recommended by lajos (7 reviews)small and light, bright, good sharpness and contrast, good at macrosnone - maybe the loud autofocus; HSM would be good
I think this is the best walk-around lens - the image quality is so much better than my previous Sigma 18-125 which was duller in colors and not sharp. The focusing is about the same - adequate but not more. The 17-70 take amazing macros: at 70 mm, it can focus on an object almost touching the glass.reviewed January 14th, 2007
8 out of 10 points and recommended by trentdp (26 reviews)Good build quality and smooth operation.Back focus at Macro/Close focus
I bought this product for about $400 a few months ago and posted a review at the time. I was excited and anticipated that the lens would perform up to my expectations given the reviews in other forums as well as this one. However, after shooting several hundred photos in a few days at lots of aperature settings and various focal lengths, I concluded that since I shoot a lot of closeup photos of landscape elements the back focus issue was just too much for me to keep this product. I very much like Sigma products but compared to the very inexpensive and suprising good performance of their 18-50 3.5-5.6 lense, this was a dissapointment for me. Sharpness in the center of the lens and good focus characteristics are prime characteristics for my work. I am an advanced amature photgrapher so you may discount my comments if you are better qualified. All other aspects of the lens were quite good and if you don't do much or care much about accurate focus at close distances then you may find this lens acceptable.reviewed January 5th, 2007 (purchased for $400)
I was somewhat reluctant to buy the lens in the 1st place because of a mention of back focus by a reviewer in another forum but disregarded my instinct and bought it anyway. I eventually returned it for a refund and Ritz Camera was 1st class in this regard.
Since my original post, I have purchased a Nikon 18-70 lens with the D70s kit. The Nikon lens is definately better for my photo work and does not have the back focus problem the Sigma had.
Maybe I just got a bad copy of the Sigma lens in regard to the focus issue but for $400 I expected this not to be an issue.
8 out of 10 points and recommended by taleyron (1 reviews)nice range, 17mm f2.8, contrast, Macro capabilities 1:2.3Need a cobra flash, from 2.8 to 4.5, lenght at 70mm, soft at 17mm 2.8
This lens is good, i only regret the sliding f2.8 to f4.5, but it should be a killer if it was constant f2.8.reviewed December 9th, 2006 (purchased for $320)
Even if it's a little soft at 17mm f2.8, on stop more and it's ok. The 17-50 tamron and 18-50 sigma 2.8 are great but their range are not so fun, i m waiting for something like a ef(-s) 16-60 f2.8 or f4 canon
8 out of 10 points and recommended by perpera (13 reviews)good allround lens, 2.8 at wide end, relatively sharp, good 'macro' performanceslow and noisy AF
Very good all-rounder for the price.reviewed November 26th, 2006 (purchased for $490)
Images are sharp and contrasty.
7 out of 10 points and not recommended by gerrysnaps (5 reviews)Sharp at the center at all apertures; close focusingf/2.8 goes away fast; bad CA; priced too close to the Sigma 18-50/2.8
The Sigma 17-70 is not f/2.8 for much of its range. By 24mm you are already at f/3.3, and by 50mm at f/4.2. This is no worse than with the Nikon 18-70 DX, but will leave those with the need for faster apertures slightly disappointed (in truth they would be better served by a constant aperture lens).reviewed June 28th, 2006
The Sigma 17-70 shares the same characteristics as the 18-50/2.8: it is sharp at all apertures at the center, then decreases in sharpness in the corners. Moving into the longer end of the focal lengths, the difference between corner and center sharpness decreases. As is the case with some macro zooms, sharpness at infinity focus tends to be soft. Here it is not bad but not great either. Bokeh is not very smooth but not that distracting. These traits make it a serviceable enough macro lens, as long as you do not need 1:1 reproduction, and a very flexible lens able to deliver sharp photos in general use.
Some flaws in this lens can be found if you look hard enough. Vignetting shows up at the wide apertures, and at the same time contrast suffers noticeably. Also, chromatic aberration is obvious at wide open apertures, and still noticeable even stopping down to as much as f/11 if the conditions are bad enough.
My full review: http://www.gadget-hack.com/2006/06/sigma-17-70mm-f28-45-dc-macro-af-lens.html
8 out of 10 points and recommended by Aksu (1 reviews)
I recently bought this lens for my KM Dynax 7D camera because its good reviews and large aperture. This lens feels sturdy and well made. The Macro capability is also very good. The pictures it delivers are crisp and contrasty for a zoom lens. At the short end of the zoom range I have experienced some focusing problems (mainly backfocus), but I think that it is more due to my camera than to the lens.reviewed June 9th, 2006
9 out of 10 points and recommended by j_scuba (2 reviews)Excelent Macro, fast lensNo manual focusing overide
This lens have excelnt macro capabilities.reviewed May 24th, 2006 (purchased for $350)
The vignetting at wide apertures is very good.
6 out of 10 points and recommended by wildcameradog (1 reviews)nice zoom range plus macro.No constant f/2.8 aperture
I got the Nikon AF mount and works fine. Noisy in use, though. Minimal pincushion at 70mm and minimal barrel distortion at 17mm. All in all, an impressive lens (my copy anyway) for the price. I have yet to test it with my SB800 flash. The reason I got this lens was to use it for weddings and other group gatherings.reviewed March 10th, 2006 (purchased for $390)