Sigma 50-150mm f/2.8 II EX DC HSM
For DX shooters, this lens offers an attractive combination of low price, wide maximum aperture, very useful range (equivalent to 75-225 mm on FX), compact size and low weight (for a f/2.8 tele zoom that is). The focal length range and in combination with the wide aperture makes it suitable for both portraits and sports.
Unfortunately, Sigma's quality control seems to have more problems than usual with this model. A number of users report that they have received brand new lenses with various defects such as uncentered elements and front-focusing issues.
Provided you can find a good sample, it is still a tad soft (but usable) on f/2.8 – in particular at the long end. Sharpness improves a lot of you stop down to f/4. It has a tiny amount of difficult to correct barrel distortion in the center of the frame at 50 mm. Around 80 mm, it turns into pincussion distortion. At 150 mm, the pincission distortion is prominent. Flare is well controlled at the wide end, but not at the tele end. Theree is also very litte CA at the wide end, but CA starts to appear around 100 mm. Vignetting is noticeable at f/2.8, but goes away at f/4.
Mechanical construction appears solid, and I have not experience any problems with it, but I am not a heavy user. However, there are reports on the net that a number of these lenses develop mechanical problems after heavy use, indicating that it may not be a professional grade lens despite the EX designation. The HSM ring-type focus motor is fast and quiet. Unfortunately, there is no tripod collar available.
Sigma claims the lens is compatible with the Sigma 1.4x and 2x teleconverters. I haven't tested those.
Rating: Ed: -, User: - (normalized, 0=useless, 50=average, 100=excellent).
Mounts: Canon EF, Nikon F, Pentax K, Sigma SD, Sony A.
Aperture range: f/2.8 to f/22.
Optical zoom: 3x.
Close focus distance (CFD): 100 cm / 3.28 ft (from sensor plane).
CFD magnification: 1:5.3 / 0.19X.
Focus: AF (built-in, ring-type).
Filter diameter: 67 mm.
L x D, W: 135 x 76 mm, 780 g.
Approximate street price: USD 749 (new, w/o tax).
Discontinued: 2011, replaced by: Sigma 50-150mm f/2.8 EX DC OS HSM.
Sigma is a family owned manufacturer of photographic equipment founded in 1961 in Japan. The company's main business is to manufacture third party lenses. However they also produce third party flash units and, since 2002, their own line of DSLR and compact cameras. Sigma's digital cameras use a special sensor, developed by Foveon, that records full color information for every pixel. In late 2008 Sigma acquired Foveon.