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Review: Sigma 18-250mm F3.5-6.3 DC OS HSM

The “all you can eat” lens!

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By Don Chick, M.Photog.Cr., CPP

What kind of genie would you need to call if you wanted a lens that is reasonably priced, has fantastic zoom range, and is super fast? We’ll let you know when we find one, but in the meantime, if you’ll settle for two out of three, Sigma offers the new 18-250mm F3.5-6.3 DC OS HSM lens for an MSRP of $800.

On my Canon DSLR (with a 1.6X lens factor) its 13.8X zoom ratio translates to a 29-400mm equivalent! Combine that zoom ratio with optical stabilization, macro capability, an MSRP of $800, and you have a lot of lens for the money.

I must admit that when first asked to do this review I was skeptical about a lens in which the manufacturer was trying to do so much in one package. There have to be compromises to balance zoom range, speed and cost, but Sigma has done a great job combining features in the 18-250mm.

The first thing that I noticed was the weight, which, at around 22 ounces, has a substantial feel and heft of quality to it. Even though the lens has that feel, the overall size is not that big. When set at 18mm, the overall size is 3.1x 4 inches long (excluding lens hood). When zoomed to 250mm, the overall length increases to about 7 inches. The markings are white against a black body, so they stand out and are easy to read. Sigma eliminates an additional expense for the user by including a lens hood designed specifically for this lens.

The first feature I checked out was the zoom range. A lens with an 18-250mm range is simply incredible. My favorite subject to photograph is people, I simply love portraiture; with this lens, though, I began to appreciate flower photography, especially small flowers. You can see the entire zoom range of the lens in Figures 1 and 2, below. 

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Figure 1 (above): 1/25 second at f/6.3, ISO 800, focal length 250mm, noise reduction applied. ©Don Chick

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Figure 2 (above): 1/25 second at f/6.3, ISO 800, focal length 18mm. ©Don Chick

In addition to photographing flowers, I took the lens to my son’s baseball game. While these images are what I refer to as “record of the event” shots (meant to record an experience and not for competition, or to impress one’s colleagues), they too reveal the zoom range of this lens (Figures 3 and 4).

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Figure 3 (above): 1/1,000 second at f/7.1, ISO 200, focal length 250mm. ©Don Chick

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Figure 4 (above): 1/1,600 second at f/7.1, ISO 200, focal length 18mm. ©Don Chick

The lens barrel has a non-slip rubber surface that you hold to focus or zoom. This material makes zoom adjustments quick and smooth, and the focus ring turns easily with little resistance. The focus ring rotates from nearest to infinity with little more than  1/4 turn, making the adjustment from one extreme to the other very quick. Since the lens barrel itself doesn’t rotate with focus or zoom, a circular polarizing filter won’t change as adjustments are made to either.

One amazing feature with this lens is the Hybrid Optical Stabilizer. When looking through the viewfinder (and zoomed to the 250mm setting), you can see a big difference when the feature is switched on because there’s not only anti-shake in the camera body, but also compensation in the viewfinder. Sigma claims that the OS will give the user approximately a 4-stop advantage over not using the feature. To test it, I photographed some paperwork. You can see from Figure 5 (below) that the optical stabilization definitely helped produce a sharper image. The most dramatic results for the optical stabilization were when I held the camera with only one hand. While this may not be the most common method of supporting the camera when taking a photograph, there may be times when this method is the only way to “get-the-shot.”

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Figure 5: Click for large view.

Sigma documentation says that the lens needs approximately one second after depressing the shutter release half way in order to produce a stable image. Photographers should bear this in mind to optimize the capability of this lens.

With the lens zoomed to 250mm and in very close to the subject, there were times when the lens seemed to struggle to settle on a focus point. However, I did find that the more contrast a subject had, the easier the lens found correct focus. Also, to overcome this issue (when photographing flowers especially) I simply switched to the manual focus mode.

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Above: 1/250 second at f/6.3, ISO 320, EV -0.33, focal length 250mm. ©Don Chick

Summary: This lens has a lot to offer and is worth serious consideration. The one primary drawback for the professional is the relatively slow aperture. While not all my wedding work is done with on-camera flash, there are times I do so out of necessity. The extensive zoom range would make this lens attractive to keep on a camera at a wedding as one would not have to keep switching lenses in order to cover the ever-changing situations encountered at a wedding. With its relatively slow aperture, this lens may not be the primary lens for a professional, but it certainly is excellent for scouting, back-up or when you want to travel light. Because of the wide range capability, I would seriously consider taking this lens along.

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