Sigma 18-250mm F3.5-6.3 DC Macro OS HSM preview: A compact and versatile trans-standard lens

Tuesday, June 19, 2012

Lens Review
Introduction | Sigma 18-250mm F3.5-6.3 DC Macro OS HSM Preview
    Sigma 18-250mm F3.5-6.3 DC Macro OS HSM

Designed for APS-C reflex sensors, the Sigma 18-250mm F3.5-6.3 DC Macro OS HSM shoots like a 27-375mm (and like a 29-400mm on Canon cameras with focal length coefficients of 1.6x). Very versatile, this lens qualifies as a macro thanks to its 29-cm miminum focusing distance at all focal lengths. As a telephoto lens, it provides a reproduction ratio of 1:2.9 - the equivalent of 1:2 using an APS-C. The lens barrel has a reproduction ratio scale printed on its side.

A travel and macro lens

Designed for APS-C reflex sensors, the Sigma 18-250mm F3.5-6.3 DC Macro OS HSM shoots like a 27-375mm (and like a 29-400mm on Canon cameras with focal length coefficients of 1.6x). Very versatile, this lens qualifies as a macro thanks to its 29-cm miminum focusing distance at all focal lengths. As a telephoto lens, it provides a reproduction ratio of 1:2.9 - the equivalent of 1:2 using an APS-C. The lens barrel has a reproduction ratio scale printed on its side.

Compact

Compact despite its 13x zoom range, the Sigma 18-250mm F3.5-6.3 DC Macro OS HSM measures only 88.6mm long with a 73.5-cm diameter, and uses 62mm filters. It weighs 470 grams - a very reasonable weight when balanced with a compact and lightweight amateur SLR such as the Canon EOS 650D/Rebel T4i or the Nikon D3200.

New TSC material

The Sigma 18-250mm F3.5-6.3 DC Macro OS HSM was built using the new TSC (Thermally Stable Composite) material, which reinforces the lens structure by limiting its sensitivity to temperature changes. While this material is very similar to metal, it has an elasticity 25% higher than polycarbonates, making it less brittle, according to the manufacturer. (The build weakness of Sigma lenses has been a source of grief for many photographers.) This 18-250mm also features a chrome-plated brass bayonet mount.

Stabilization, HSM, SLD glass lens, and SML coating

Other features of this Sigma trans-standard lens include optical image stabilization and ultrasonic (HSM) autofocus. Its optical formula incorporates an SLD (low-dispersion) glass element to correct chromatic aberrations, and three aspherical lens elements, two of which are doubly-aspherical not just to further correct chromatic aberrations, but also to correct astigmatism. Finally, the lenses have been treated with a Super Multi-Layer (SML) lens surface coating that reduces flare and phantom images.

Price and availability

The Sigma 18-250mm DC Macro OS HSM for Canon mounts will come out in July 2012, followed by Nikon, Pentax, Sigma and Sony versions. Announced price: 599 euros (tax included).

Principal characteristics

  • Focal lengths: 18–250mm
  • Zoom range: 13x
  • Maximum apertures: f/3.5–5.6
  • Circular diaphragm with 7 leaves
  • 1 SLD glass lens element
  • 3 aspherical lenses
  • Super Multi-Layer (SLM) lens coating
  • Filter diameter: 62mm
  • Lens diameter x length: 73.5 x 88.6mm
  • Weight: 470 grams