on July 31, 2013
OK, so I REALLY WANTED to love this lens . . .
This is a long review. I like to write. I hope folks will find my story interesting and helpful.
I struggled for weeks to decide on my “next” DSLR lens. After hours staring at specs, searching for prices, and digesting review after review, three contenders emerged. They were: the Sigma 18-250mm for $399, the similarly designed Canon 18-200mm for $699, and the Canon 24-105 f/4 L for closer to $1,000. OK, so that’s a big price range. Stay with me to the end and this will make sense. . .
The Sigma 18-250mm could be considered a good “litmus test” to clarify your personal goals as a DSLR owner. If you are using your DSLR to take "pictures" then you may really enjoy this lens. For the money, it delivers quite a lot. If, instead, you use your DSLR to take "photos" then this lens is probably not going to be for you. I want to characterize the lens on this basis, because it's really only a "good lens" or a "bad lens" based on what you expect from it.
Let's start with disclosures: I’m a total amateur. I own a Canon T2i (EOS 550D) and “sort of” know how to use it. I originally decided to pop for a DSLR in order to get faster instant-on-to-first-shot performance for taking pictures of my kids. Once I started using the T2i, I fell in love with what the camera could do. Beyond the kit EF-S 18-55mm lens, I next bought the EF-S 55-250mm. The 55-250mm is a solid, inexpensive, long telephoto lens that will let you take nature shots, action shots, etc. – I bought it for soccer games. Together, these lenses give you a nice wide-angle to medium-telephoto range. But, let’s be honest: changing lenses is a pain. The Sigma 18-250mm is designed to replace this standard Canon EF-S combination, and give you the 18 – 250mm range without changing your lens. If replacing this combination is your goal (or if you only have the 18-55mm,) then the Sigma may be what you are looking for. If you’ve got the budget, however, you should definitely consider the more expensive Canon 18-200mm. (I’ll only indirectly address the Canon lens in this review.)
My problems with the Sigma stem from the third lens I purchased for my T2i: the Canon EF 50mm f/1.8, affectionately known to many as the "Thrifty Fifty.” When I took my first looks at shots taken with this lens, I stopped wanting to take "pictures" and started wanting to take "photos" – the impact was overwhelming! If you own a Canon DLSR, consider yourself a relative beginner, and DON'T own the Thrifty Fifty, then you should stop reading this review right now, and go out and buy yourself a Thrifty Fifty immediately. For a mere $150.00, you will be absolutely blown away by what your camera's sensor can actually do! The kit lenses are excellent. However, when you see the razor-sharp focus, incredible detail, and beautiful bokeh (foreground & background intentionally out of focus,) that the Thrift Fifty delivers, you’ll be amazed. Why do I mention all of this detail? I think it’s helpful to explain what I actually knew about lenses when I decided to try out the Sigma. So here goes…
- The zoom range of the Sigma is why you buy it -- having 18 to 250mm available in a single lens is just really, really convenient. There’s almost no shot you won’t get.
- The lens is relatively lightweight given its range. I carried it daily for the better part of a week, and never considered the weight an issue. (It is a good bit heavier than either of the kit lenses. I’m told it weighs about the same as the Canon 18-200mm.)
- The build quality is very nice. I have friends who swear by Sigma lenses, and now I can see why. It is solid, well manufactured, and aesthetically pleasing
- Sigma's OS (Optical Stabilization) is quite good. OS won’t help you too much in a low-light situation, but it will effectively combat camera shake when shooting handheld outdoors, which is what this lens is for: walking around with a single, do-it-all lens.
- f/3.5 performance at 18mm is very nice, especially when combined with Sigma’s OS. You won’t get brilliant light like you can with a faster (f/2.8, f/2.0, f/1.8) lens, but it will help tremendously when there is enough light available.
- For $399, the price / performance of this lens is really quite impressive. I can’t say that you should expect more for your money. If you are tight on budget, want lots of capability, and aren’t a freak about image quality, you will be very pleased with this lens.
- Because of the Thrifty Fifty, I’m now a freak about image quality. Sadly, adding the Sigma to my lens collection felt like a step backward. Yes, I got the shot, but I tended to be unhappy with it . . . here come the details . . .
- At all focal lengths except 70 - 120mm, the Sigma’s shots were soft. Pixel-peeping (zooming way in with your photo editing software; something that amateurs really shouldn’t be doing…) on all shots taken outside of this range, I was disappointed that I was not seeing crisp, sharp details. Softness is understandable at long zoon, but from 18mm to 70mm, things should be sharp.
- Significant CA. Honestly, I didn’t really understand what Chromatic Aberration (or, CA) was before owning this lens. CA is the tendency of red and green light to separate at the edges of an image. It happens because the different wavelengths (colors) of light bend differently, and so they don’t line up together when focused through a complex lens. Apparently, all lenses suffer from some degree on CA. However, it’s particularly a problem on zooms with a wide range. Unfortunately, I found the Sigma to suffer quite badly from CA, resulting in significantly degraded image quality. For me, this was the killer.
- Lens creep. Many zooms suffer from what’s known as "creep," where the lens barrel will extend (undesirably) under its own weight. I use BlackRapid strap (which I highly recommend) that attaches to the camera’s tripod mount. Because this design means that the lens points towards the ground when being carried, any lens that does creep, will creep. The folks at Sigma obviously anticipated creep, because they included a zoom lock, which lets you lock the barrel at the 18mm position. Unfortunately, this results in constantly locking & unlocking the lens, which quickly becomes a pain. It this a nit-pick? Maybe. But for reference, I’ve never had my Canon 55-250mm creep. (Perhaps this issue is not such a big deal with other straps, but it was definitely an “annoyance” with my set up. At least they included the zoom lock!)
- Is it really 250mm? One of the odd things I noticed during my checkout was that photos taken at full zoom (250mm) on the Sigma somehow seemed different from those taken at 250mm on my Canon 55-250mm. So, I did a test. I took the same shot and actually measured the captured image. I was stunned to find a 40% difference! The Canon lens seemed to zoom much farther than the Simga – what’s up with that?! I queried some forums and got educated on “lens breathing” which can sometimes account for this type of difference. However, the consensus from several experts was that a 40% delta could not be explained solely by lens breathing. In the end, I left this as a bit of a mystery, but caveat emptor – I am still wondering if Sigma’s 250mm was really 250mm, or maybe just 200mm…
- Barrel friction. Apparently one of the big mechanical challenges of long zooms is getting just the right amount of friction in the barrel, and keeping it consistent. The Sigma underwhelms here; there is very obvious “stickiness” between 70 and 200mm. Perhaps they were intentionally trying to make it sticky to avoid lens creep? The upshot is that as you zoom from 18 towards 250, you hit big resistance for about a ½ turn. Once I got used to it, it wasn’t a huge deal. Ideally, it shouldn’t be there, but there you have it.
So, why did I return this lens? No question: Image Quality.
At the end of the day, I realized that for me, taking a step back on image quality wasn’t worth the convenience of this massive zoom range. During my checkout, I aggressively researched lens design, and read dozens upon dozens of reviews of zooms of various ranges. My conclusion is that outside of wildly expensive professional lenses, you must be willing to accept tradeoffs in a consumer super zoom. In the case of the Sigma, while they maintain good aperture performance and wonderful zoom range, these features come at the expense of Image Quality. For me, this was a deal-breaker. For you, it might not be.
So, for the amateur-recently-turned-IQ-snob, what lens to buy instead?
After countless hours poring over reviews and asking friends, a clear direction emerged: I was going to have to sacrifice zoom range if I wanted better, faster glass. There were dozens of contenders out there: Canon, Sigma, Tamron, Tokina. The winner? The Canon 24-105mm f/4 L. Although nominally priced at $1,149.00, white box copies of this lens are now showing up at $799. So, is it worth 2X the money to get less zoom range but upgrade to one of the legendary Canon “L” lenses???
Giving up wide angle from 18mm to 24mm really didn’t worry me too much. At 18mm, most of the group people shots I’ve taken have been easily inside the frame. Looking across the wide-angle shots I had taken with the Sigma, I also noticed that many of them were actually at 22m, instead of 18mm. So, bumping from a maximum wide of 22 to 24 didn’t seem like too much of a sacrifice for me – so, maybe I just have to take another step back from my subject to get the shot. Big deal. If the shot is going to look MUCH better, I can take one more step back….
In contrast, the prospect of giving up telephoto from 250mm (if it really was 250…) all the way down to 105mm, did worry me… a lot. Should I just be happy with the 55mm max range on my kit lens and save my money? Should I just continue to use my 55-250mm for these longer-range zoom shots? Should I try the Canon 18-200mm instead? After all, if my intent was to have “just one lens,” what would having the extra 50mm provided by the original kit lens really buy me?
Then I remembered the Thrifty Fifty.
One of the amazing things I discovered when first playing with it was that far-away objects, when in focus, were still very, very sharp. So sharp, in fact, that with 18MP to play with, I could shoot a far-away object, crop the shot, and still have a nice end result. So, couldn’t I do the same with a very sharp shot at 105mm? If I wanted to zoom to 200mm and could only do 105mm, if the shot was sharp enough, would I be happy with a cropped image? And there was my answer . . . yes.
The 24-105mm f/4 L blows away the Canon 18-55mm, the Canon 55-250mm, and the Sigma 18-250mm throughout its entire range. At every focal length, its performance is simply superb. So, while it may have minor limitations for shot framing and composition, it completely wins by enabling the best results all the way across the middle part of its zoom range. Still, the question lingers: is it worth 2X the money given the zoom range sacrifices? Well, let me just say this: I’m once again giggling when I review my shots at the end of a day. The Image Quality of the f/4 L is just off the hook, and I can’t imagine going back – I haven’t had this much fun since the 50mm f/1.8. Even when the lens is stopped down to 5.6 or more, the sharpness of the images are just astounding. So long as you keep the ISO below 800, the lens delivers amazing IQ across its aperture range. There is no question that it is the winner from 24mm to 105mm at every length.
At the end of the day, you need to assess the Sigma 18-250mm based on your own personal goals. For me, it was an interesting and educational detour that taught me how much I value IQ. For you, the lens might be a terrific expansion that brings you lots of creative results. Just know that lenses are priced based on very mature and active consumer markets. You will get a lot with this lens, but you won’t get everything. Just make your decision based on how you take pictures, and you’ll be satisfied.
I’m very glad I got a change to shoot this lens – thank you Amazon for your generous exchange policies. At the end of the day, both Amazon and Canon got more of my money, and I got more satisfaction. As much as I enjoyed the Sigma, I’m enjoying having splurged for the f/4 L even more!