Sigma APO 100-300/4 EX IF HSM specifications Sigma APO 100-300/4 EX if HSM

Lens Review...

Sigma APO 100-300/4 EX IF HSM

Text and Photography Copyright Jim Erhardt

All rights reserved.

The decision of what lens to buy for wildlife photography always seems mired in compromise. Along with the budget limitations most of us face in buying equipment, the debate over prime lenses versus zooms, and "original equipment manufacturer" versus "third party manufacturer" cloud the decision making process as well.

While just about every manufacturer offers at least one model in the 75mm (or 100mm) to 300mm range, just about all of these lenses are variable aperture lenses, typically f/4.5 to f/5.6. Along with the slower shutter speeds associated with the use of these models, the addition of a teleconverter will usually result in the loss of autofocus operation and substantial degradation of optical performance. However, for the nature photographer there's no denying the utility of a telephoto lens in this zoom range.

Sigma's latest telephoto zoom lens, the APO 100-300/4 EX IF HSM finally provides a very

viable alternative for the serious nature photographer looking for a telephoto lens in this range of focal lengths. Along with the handy range of focal lengths, it provides a constant f/4 maximum aperture, internal HSM focusing and internal zooming. In other words, regardless of zoom or focus setting, the lens does not change in physical length and the maximum aperture of f/4 is available at all focal lengths. Additionally, the lens can be used with Sigma's EX series of teleconverters. I recently had the opportunity to spend some time with this lens (and Sigma's matching 1.4X teleconverter) in a Canon mount.

Like Sigma's other EX super-telephoto lenses, the lens is far more solidly built than the typical "consumer" version of the 100-300 zoom. It features a wide, very smooth turning focus ring and a separate zoom ring, which is large and smooth in operation as well. The Sigma, Canon and Nikon mount versions of this lens include Sigma's HyperSonic Motor (HSM) focusing motor, which also allows for full-time manual focus override. The lens also includes a removable tripod mount collar, a very handy feature for the nature photographer. The lens features Sigma's attractive black-speckled EX finish and is supplied with a large matching lens hood. Overall, the build quality of this lens is very impressive.

Other specifications include -

●16 elements in 14 groups optical construction, including two Special Low Dispersion (SLD) elements

●9-blade aperture (f/32 minimum aperture)

●180cm/70.9 inches minimum focusing distance (1:5 magnification ratio)

●92.4mm (3.6 inches) maximum width by 224mm (8.8 inches) in length

●1480 grams (52.2 ounces) in weight