Sigma's fast constant-aperture telephoto — the 100-300mm f/4 for Canon EF professional use.
The Sigma 100-300mm f/4 EX DG HSM APO IF is a professional constant-aperture telephoto zoom for Canon EF mount. The constant f/4 provides one stop more light than typical f/5.6 telephoto zooms and consistent exposure throughout the range. APO elements ensure chromatic correction. HSM motor provides fast, quiet AF. A practical sports and wildlife zoom.
Optical performance is good. Sharpness is very good from f/4 throughout the range. The constant f/4 is the key advantage — brighter viewfinder, faster shutter speeds, and more DOF control than f/4.5-5.6 alternatives. APO elements with IF design control aberrations well. The 100-300mm range covers the essential telephoto zoom spectrum.
Canon EF mount. Filter thread is 82mm — large. Weight is approximately 1,310 grams — heavy. Build quality is solid EX professional grade. HSM motor is fast and quiet. No image stabilisation — the main limitation. Tripod collar included. IF design prevents barrel extension. Compatible with Sigma teleconverters for extended reach.
Available at moderate used prices. Check AF accuracy and smooth zoom. The constant f/4 remains practical for sports and wildlife in good light. The lack of IS limits handheld use at 300mm. The Sigma 100-400mm Contemporary offers more reach with IS at a lighter weight. Best for tripod or monopod-based telephoto work.