Sigma 70-300mm f/4-5.6 DG Macro
This inexpensive an light lens (for the zoom range) from Sigma exists in two almost identical versions. This slightly cheaper without “APO” in the name does not have the two extra SLD (special low dispersion) glass elements that makes the APO version slightly better (however, it has a single SLD element.) You can tell the two apart visually by the non-APO-version not having a red stripe around the forward part of the lens barrel.
As indicated by the price, this lens is in the consumer segment. Mechanically, it appears identical to the APO-version. Optically, it is slightly worse, with less “punch” and sharpness over the range.
Normally, the lens has a min. focus distance of 150 mm, where the magnification is 1:4. However, once the lens is extended past 200mm, there is a sliding switch that enables “macro” mode. This allows the focus ring to travel further. In this mode, maximum magnification is half life size.
Mechanically the lens is clearly consumer grade. It is made mainly of plastic, but the mount is metal. The front element rotates during focusing. The autofocus is slow and noisy.
For someone who is on a tight budget, this lens may hold some attraction. It is not, however, a lens I would want to use.
Rating: Ed: -, User: - (normalized, 0=useless, 50=average, 100=excellent).
Mounts: Canon EF, Nikon F, Pentax K, Sigma SD, Sony A.
Aperture range: f/4-5.6 to f/32.
Optical zoom: 4.3x.
Close focus distance (CFD): 95 cm / 3.12 ft (from sensor plane).
CFD magnification: 1:2 / 0.5X.
Focus: AF (built-in, gear-type).
Filter diameter: 58 mm.
L x D, W: 120 x 78 mm, 530 g.
Approximate street price: USD 159 (new, w/o tax).
Introduced: no data.
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.