By Don Chick, M.Photog.Cr., CPP
The new Sigma APO 50-500mm f/4.5-6.3 DG OS HSM lens with its 10X zoom range is one impressive lens. Sigma pitches this lens as the “all-in-one” dream lens, especially for nature photographers. It’s also suitable for landscape photography and has enough zoom for photographing wildlife. I have to agree with Sigma.
This lens is designed for full-frame DSLRs, but also functions with cameras with APSC- size sensors. Using the 50mm setting (a 35mm focal-length equivalent to 80mm on my Canon 40D), I photographed a nuthatch in a tree (Figure 1). As you would expect, it’s tough to even find the bird in the image. Zooming to the telephoto end of the range, 500mm (the equivalent of 800mm on my Canon 40D), I was able to capture the nuthatch in great detail (Figure 2).
Figure 2. ©Don Chick
At the 200mm setting, the lens has maximum magnification of 1:3.1, at a minimum focusing distance of about 20 inches, enabling you to get close-ups of small subjects (Figure 3). If you were backpacking to a location and wanted to carry minimal equipment, this could be your best bet. Note, however, that the lens is not waterproof.
Figure 3. ©Don Chick
The optical stabilizing (OS) feature of the lens is another selling point. I was able to handhold the camera for shots that otherwise would have required using a tripod. The OS doesn’t instantly kick in when you press the shutter button. Sigma recommends pressing the button halfway down and confirming that the stabilization is engaged before capturing the shot; it could take up to one second. You can easily see when it does engage in the viewfinder, as the effects of camera shake virtually disappear. Sigma recommends switching off OS while connecting or disconnecting the lens to the camera. Do read the specs to get familiar with the lens’s characteristics and the best operating practices.
The zoom and focus mechanisms adjust quite smoothly. The quiet, hypersonic motor (HSM) quickly determines the focus point. The lens weighs in at 4.34 pounds, so it's a big benefit that the tripod collar is ergonomically designed with indentations for your fingers, providing a comfortable grip for carrying. The weight of the lens could induce fatigue if you handhold the camera for an extended period of time. The lens is also very long, about 14.75 inches fully extended with the lens hood in place.
Because of the 95mm filter size, you'll want to remove the lens hood when you use something like the ExpoDisc or ColorRight white balance devices, which are designed to be held in front of the lens. This will minimize the chance of stray light striking the front of the lens.
The zoom, coupled with the optical stabilization features, help make the Sigma APO 50-500mm f/4.5-6.3 DG OS HSM a valuable addition to an equipment bag for the serious nature, landscape or sports photographer.
It would be nice to have a bit more speed with this lens (f/4.5-6.3), especially at the long end of the zoom range, but sacrificing a little bit of lens speed helps to keep the price of the Sigma 50-500mm affordable to serious photographers: $2,400 MSRP.