Sigma 70-300mm f4-5.6 DG OS Optical Stabilised Lens for Canon Digital and Film SLR Cameras

I have only had 2 days to play with this lens, but so far am impressed with it's performance. I bought this mainly for outdoor use as I have a Nikon 70-200 f2.8 VR lens for indoor shooting. I simply do not want that mammoth lens on my camera when hiking, etc., especially since fast aperture is not necessary in good light. This one looks like it will do nicely. Focus is pretty fast - hunts a little in lower light at telephoto, but that's pretty common for most lenses of this type. Image quality is very good so far. Some very minor fringing in a few of the shots (not an issue with JPEG's from my D90 because it automatically removes most CA). I'll shoot some RAW shots outdoors when I get a chance to see if it is anything to worry about, but so far it appears to be acceptable. Focus is extremely accurate - dead-on on every shot taken (no front focus issues that some Sigma lenses have). OS is also VERY impressive. I'd say really close to Nikon's best VRII lenses. I took a couple of 1/4 sec. shots handheld with only my elbows braced against my ribs, at full telephoto, and the shots were perfectly sharp. You can see the image start to float when the shutter is half-pressed, so you know the stabilizer is working. Lens mounts snugly onto the camera and has a good, sturdy metal mount like the better Nikon lenses have. Fits perfectly. I like the size and weight compared to the Nikon equivalent (it is somewhat more compact). The only drawback is that the lens is not internal focusing like the Nikon (which probably accounts for the compactness). This means that the lens hood must be a round one (not a petal hood, which I prefer) because the end of the lens rotates as it focuses. It also extends about 7/8 of an inch at closest focus, which makes the overall length pretty long at 300mm (about 8 inches without hood, around 10 with the hood attached). None of that really matters much to me, though. One thing that I liked about this one compared to the Nikon 70-300 VR was that the aperture starts at f4, not f4.5, so it's a bit faster than the Nikon. The shallow depth of field was surprising to me. Longer focal lengths tend to really amplify the effect at closer ranges, and that is very apparent with this one.
The best way to rate this lens would be to break down specific attributes, and then give a score (1 to 10) on that attribute, so here goes:
Image quality (so far): 9 (impressed with every one taken thus far - color, sharpness, etc. quite good)
Focus accuracy: 9 (low light the only issue)
Focus speed: 8 (could be a little better)
Focus noise: 7 (not as quiet to focus as Nikon AF lenses - even my huge 70-200 f2.8 VR lens is lots quieter)
Fit: 10
Finish quality: 7 (surface not as good looking or durable looking as Nikon, but not ugly either)
Optical Stabilization: 9.5
Size/weight: 9
Overall ease of use/functionality: 9
I will update with more information after using the lens more. I cannot give the lens 5 stars, although I believe it is not far from achieving that. I think most people will agree that this lens is worth the money spent and will do what it is intended to do, and do it well.

Update: Feb. 2010- Have taken a few more shots with this lens. All-in-all still very satisfied with it. The fringing noted earlier is there - a bit more than I first indicated. RAW shows slightly more than the JPEG's, but it is fairly easy to remove the majority of it in Lightroom. Some images look a bit soft. When I compare them to the 18-105 Nikon kit lens, I initially thought they were pretty comparable,but they are a tad bit softer when looked at closely. It is much softer than my 70-200 f2.8, even when that one is shot wide open - and the Sigma is FAR behind on anything stopped down to f4 or higher on the Nikon. However, I would expect nothing less from a lens that is over 5 times as expensive. Outdoor shots are very respectable from the Sigma - It is my recommendation that a person use this lens stopped down some outdoors, particularly at 200mm and above, as the fairly shallow depth of field when zoomed will render some subjects in front of the main subject out of focus, even on relatively distant shots. F8 to f11 fixes that most of the time. My initial rating of 4 stars still stands, as I feel that image quality is less than perfect, but as good as anyone should expect at this price level. The only individual rating that would change is the image quality that I rated a 9, is more like an 8 - still pretty good. Is is considerably better than a Nikon 55-200 VR that I sold recently - it was soft across the frame, with a very bad left side. Perhaps a bad copy? Anyway, the Sigma 70-300 OS is a lens I am proud to carry in my gear bag, and one that will work well for me for a long time.

Update 2: Mar. 2010 - Upon further inspection of the images, it appears that shots taken stopped down some are a fair bit sharper than when shot wide open. Stopped down shots look to be sharper than just about any of the Nikon 18-105 ones, but are softer than the Nikon when shot wide open. That being said, my recommendation in a sentence or two is: shoot this lens stopped down a bit and don't expect to use it in low light without flash or for indoor sports. The best shots will result from the lens set too slow to be of much use in those cases. If I have more to report, I will do so later.

First a few words of caution about this review: Newb to dSLR's here!

I recently made the decision to get a dSLR due to my recent frustration with a point-and-shoot at the Cherry Blossom Festival in D.C. I just couldn't get a picture of what I was seeing. No fiddling with the point-and-shoot would capture it.

I purchased the Canon Digital Rebel XSi 12.2 MP Digital SLR Camera with EF-S 18-55mm f/3.5-5.6 IS Lens (Black) from Amazon. WOW! What a difference this intelligent and capable piece of art can make. I read reviews that said shoot with it for a bit until you decide what you like to shoot before getting an additional lens. I took that advice and after a couple of weeks, decided I wanted a zoom with a bit of reach. After much trepidation due to the expense, I decided on a 70-300mm. In researching, I found the Sigma 70-300mm F/4-5.6 DG OS SLD Super Multi-Layer Coated Telephoto Lens for Canon AF Mount Digital SLR Cameras. I just couldn't justify the additional expense of the Canon EF 70-300mm f/4-5.6 IS USM Lens for Canon EOS SLR Cameras. Both seemed to have the same basic features with the Canon having USM and better reputation and slighty better reviews. The Sigma, however, seemed to hold its own in reviews especially for this amateur.

After having the Sigma for better than a week and being quite impressed (again an amateur's point of view), I began wondering just how much better the Canon could be. I began an online search for pricing and was surprisingly able to run across a new Canon on eBay for the same price. New for the same price!! I pulled the trigger instantly figuring if I like the Canon better, I could return the Sigma. If I liked the Sigma better, I could most likely sell the Canon at a profit.

I received the Canon two days after the purchase and here are my assessments.

-My out-the-box impression was wow, this thing is built much more solidly than the Sigma. Where the Sigma is plastic, the canon is metal. The Canon has more heft and girth and it looks and feels more professional to this amateur. The Sigma has the velvety coating and the Canon is nicely finished metal. But that's just the look.

-I shot a few shots using program at various focal lengths and did a side-by-side comparison. The clarity, to my old eyes, of the Canon was better in all cases.

-Performance wise, I could not tell much difference in focus speed of either. The Canon's USM during focus is very quiet where the Sigma could almost wake the dead.

-The feel of the zoom ring operation on both is equivalent, with the smoothness of the Canon slightly edging out the Sigma. I wouldn't weigh that heavily in the decision though.

-The OS in the Sigma is great, but it has a tendency to kind of float around in the viewfinder ever so slowly which affected me when shooting at full zoom with center only focus selected on a small object. It seemed I had to keep moving the camera to keep the focus dot at the point I wanted to focus on or time the shutter to snap when the focus point was lined up. I felt like this could contribute to more blur caused by me doing so. The Canon's IS is rock solid in this respect, perfectly still in the viewfinder. The Sigma's OS noise sounds like a very quite whirring sound almost spooky. The Canon's is noisier with more of a gear sound. Although I haven't had a chance to try it yet, the Canon has two modes of IS: mode one for horizontal AND vertical and mode two for horizontal OR vertical only. The Sigma, to my knowledge, does not do one direction only.

-The Canon also has a zoom lock to keep the lens from extending when walking around. The Sigma does not. The Canon seems tight enough, but it is new. I'm not sure if this is necessary, but if it is, I'm glad to see it. I don't know if the Sigma would ever get loose enough to extend during walking. If it does, then there is no lock.

-The minimum aperture of the Sigma is f/22 where the Canon goes all the way to F/32. My amateur knowledge doesn't know if this will be a factor, but just a point of difference between the two lenses.

-The Sigma comes with a lens hood and the Canon does not. The Canon branded hood cost more than $40!!! if you can find it. There seems to be satisfied people with non-Canon hoods at much more reasonable prices.

Conclusion: Would I recommend the Sigma to someone who had to stretch the budget to get it? Yes. From what I experienced, it is a really nice lens. If, like me, you agonized between the two because of justification and then got the opportunity to shoot with the Canon (not to mention getting it new for the same price), then go for the Canon which is slightly over a $100 more on Amazon. I'm reading Canon EOS Digital Photography Photo Workshop which is a great book and the guy continually stresses the superiority of Canon lenses. However, he only shoots L-series glass, but says the non-L series are still better than most. I guess in the case of the Sigma versus the Canon, I would say the Canon is the winner.

Camera:
I'm the proud owner of a Pentax K20D, which is also my first DSLR (and SLR in general).

Experience:
Took up photography this past summer (summer 2009), but I've put a lot of time and research into it so far. But I'm far from a professional, of course.

Previous Lens(es):
Pentax 16-45mm f/4.0 SMC PDA ED AL Zoom Lens for Pentax and Samsung Digital SLR Cameras which, by the way, I have been pleasantly happy with so far as my standard lens. It's also great for me personally, because of my landscape/panorama interest.

Ownership Time:
~A week

Review:
This lens performs its duty well. I'll break the review down into further sections:

Auto Focus Feature: It focuses fairly quickly, smoothly, and accurately in decent light, and hunts around for a little bit in low light settings (took it into my windowless bathroom and left a crack in the door), but not as much as other consumer (price-wise) telephoto lenses.

Auto Focus Sound: To me it's a pretty soft sound/not too loud, but you will notice it.

Optical Stabilization (OS): Works amazingly and wonderfully, and it can stack with the anti-shake feature built-in to the Pentax body. Slight caveat though-- it makes this high pitched humming sound when it's working, maybe not audible to older ears (no offense here), and definitely not audible in louder areas such as sports events, but when you're using it quietly indoors-- you might have a slight problem with those sitting next to you. You do get used to it after a bit though, and it stops as soon as you stop using the OS feature (finish the shot/stop pressing the shutter half-way).

Weight and Dimensions: It's fairly big (I believe the dimensions of 3 x 5 x 5 in the description is severely understated), but smaller than other telephoto lenses from what I understand. It's got a bit of heft to it too, but not back-breaking or anything; it IS significant though, so keep that in mind if you plan on bringing it on a long hike or something (maybe walk around with it + your camera gear in your camera bag for an hour or so just around the house to see if it's manageable).

Functionality and Performance: It does what it's supposed to, and quite good at it too. As usual, with full telephoto range (300mm), shaking and stabilization become a big factor and issue; the optical stabilization helps a lot, as does the built-in Pentax anti-shake, but you're still definitely going to want to bring a tripod if you have shaky hands, or want very clean pictures. This is an issue with most if not all telephoto lenses though. The zoom on it is nice, and make sure you do pay attention to the fact that it has a minimum focusing range. The fact that it's f/4.0-5.6 instead of f/4.5-5.6 means a little quicker shots, which is definitely a plus over the competitors. Update: So, low lighting/indoor situations, as predicted, are not too great with telephoto lenses; the low shutter speed you have to sacrifice for, if you're going into telephoto ranges, makes it impossible to get a clean shot (without blur) sometimes; have something to brace against, or as I said before, a tripod. I'll be updating later on nature + outdoor shots.

Quality of Shots: The quality of shots is extremely nice; I haven't noticed any vignetting or aberration in the photos, but so far they're been indoor + medium-lighting shots. Blur is an issue with telephoto ranges, as mentioned before, because image stabilization can be only so good. More updates to come.

Ease of Use and Installation: It's very easy to install, just line up the focus line with the arrow and then turn it until the click-- it's very snug and fits well. To use the auto focus mode, switch the tab from (M) to (AF), and do the same on your camera (from (MF) to (AF.C) [confirmed to work] or (AF.S)). Optical Stabilization (OS) is also a tab, and you can switch it between On and Off; if it is On, it uses the camera's battery and will drain battery faster than normal-- so turn it off if you do not need it. Focusing ring and zoom ring are standard fare; although, if you have the lens hood on (or filters), beware-- if you point the camera/lens straight down, the focus ring may shift and the front of the lens "pulled" out by gravity. So far, it seems to only be happening sometimes, so I think it's a common occurrence; I could be wrong and just have gotten a defective one (kind of a big pet peeve for me, so it loses a star in "Quality of product" for that).

Overall Verdict:
If you are looking for a fairly good, well-priced, third party telephoto lens (for your Pentax, or they make them for other brands as well), then you may very well want to consider this. With premium optical stabilization capabilities, the quality of which is usually only found in higher-end models, and auto-focus that works with the body, this is definitely a telephoto lens you should not miss out on. If you are a professional or are aiming to utilize close-up shots/telephoto lenses a lot more often as your default lens, then you might want to wait to just get a prosumer/pro one, but for me as just a secondary lens, and also on a tighter budget of a consumer, this was an excellent deal for me.