Sigma APO 50-150mm f/2.8 EX DC OS HSM Lens


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    Sigma APO 50-150mm f/2.8 EX DC OS HSM Lens

      In summary

      Sigma's new APO 50-150mm f/2.8 EX DC OS  HSM lens is one of only two large-aperture tele-zoom lenses for cameras with APS-C sized sensors. (The other is the Tokina AT-X 535 Pro DX AF 50-135mm f/2.8.) Distinguished from its predecessor by the addition of Sigma’s proprietary OS (Optical Stabiliser) system, which claims up to four f-stops of camera shake correction, it will be attractive to wedding and portrait photographers.

      Buy this lens if:
      - You need a fast, effectively-stabilised lens for portraiture or product photography.
      - You want a zoom lens that can be used with polarisers and graduated filters.
      - You require good flare resistance in backlit situations.

      Don't buy this lens if:
      - You have a camera with a 'full frame' (36 x 24mm) image sensor.
      - You need a small, lightweight lens.

      Full review

      Sigma's new APO 50-150mm f/2.8 EX DC OS  HSM lens is one of only two large-aperture tele-zoom lenses for cameras with APS-C sized sensors. (The other is the Tokina AT-X 535 Pro DX AF 50-135mm f/2.8.) Distinguished from its predecessor by the addition of Sigma’s proprietary OS (Optical Stabiliser) system, which claims up to four f-stops of camera shake correction, it will be attractive to wedding and portrait photographers.

      Side view of the Sigma APO 50-150mm f/2.8 EX DC OS  HSM lens without its tripod collar and lens hood. (Source: Sigma.)   

      The 50-150mm focal length covers angles of view equivalent to 80-240mm in 35mm format on Canon cameras, 85-255 on the Sigma SD15 or 75-225mm on Nikon DX or Sigma SD1 bodies. This lens has a minimum focusing distance of 80cm and a maximum magnification ratio of 1:6.3.

      Sigma has revised the optical design of the lens to include its proprietary OS (Optical Stabilizer) system and this makes the new lens quite a bit larger, heavier and more complex. Six SLD (Special Low Dispersion) glass elements are included to compensate for colour-related aberrations, while use of Super Multi-Layer coatings minimises the effects of flare and ghosting. The main differences between the new lens and its predecessor are shown in the table below.

       

      APO 50-150mm f/2.8 EX DC OS  HSM

      AF 50-150mm f/2.8 EX DC HSM 

      Optical construction

      21 elements in 15 groups

      18 elements in 14 groups

      Exotic elements

      6 SLD elements

       4 SLD elements

      Stabilisation

      Yes

      No

      Minimum focus

      80 cm

      1.0 m

      Maximum magnification

      1:6.3

       1:5.3

      Filter size

      77 mm

      67 mm

      Dimensions (D x L)

      86.4 x 197.6 mm

      76 x 135 mm

      Weight

      1.34 kg

      770 g

      Tripod mount

      Yes

      No

      Like its predecessor, the new lens has internal focusing and zooming systems, which means it remains the same length and its front element doesn't rotate, allowing easy use of polarisers and effects filters. Sigma's HSM (Hyper Sonic Motor) ensures quiet and fast autofocusing and supports full-time manual focus override.

      A nine-bladed iris diaphragm closes to a circular aperture for attractive bokeh. The tripod collar is removable and the lens is supplied with a generous, petal-shaped lens hood, front and end caps and a carrying case.

      Build and Ergonomics
      The lens barrel of the is very solidly built from a combination of metal and polycarbonate plastic. The lens mount is also metal (probably chromed brass). It fitted snugly on the Canon EOS 40D body we used for our tests and was a better match for the larger and heavier body than with the entry-level EOS 1100D.

      While its size and weight (1.34 kg) make it a bit too heavy for bushwalking and everyday shooting, its range can be extended with Sigma's 1.4x or 2x teleconverters, which reduce the maximum aperture to f/4 and f/5.6 respectively. While either would make the lens usable for shooting sports or wildlife, the lack of weatherproofing could be a disadvantage in either situation.

      The 45 mm wide zoom ring is located approximately 25 mm back from the front of the lens. It has a 35 mm wide ridged, rubber grip band. Engraved on the ring just behind this band are focal length markings for 50mm, 70mm, 100mm and 150mm, which are lined up against a white mark on the fixed section of the barrel behind.

      The focusing ring is located just behind this mark. It's roughly 20 mm wide and carries a 9 mm wide grip band with slightly narrower ridges than the zoom ring. Both rings provided slight resistance when turned but moved smoothly and positively.

      A distance scale is inset into the lens barrel just aft of the focusing ring. It carries markings in feet and metres ranging from the closest focus (0.8 m/2.6 feet) to infinity.

      The AF/MF and stabiliser sliders are located on the same section of the lens barrel to the left hand side of the distance scale. Two OS (Optical Stabilisation) modes are provided: Mode 1 provides generalised steadying for normal usage, while Mode 2 is designed for use during panning, when subjects are moving horizontal to the camera. There's also an 'off' position for when the lens is tripod mounted.

      The tripod collar is located roughly 20 mm behind the sliders, with its trailing edge about 30 mm from the camera body. A large, knurled clamping screw holds the collar in place and a line on the collar is matched to a white dot on the lens barrel when the camera is positioned for horizontal shooting, with a white dot just beside the screw used when the camera is positioned vertically. 

      The supplied lens hood is large but easy to fit and solid enough for everyday usage. It has indexed points that help you to line up the bayonet mounting and the hood click very positively into place.

      Performance
      Our tests showed the review lens to be a superior performer in almost every way.  Autofocusing was fast and accurate and we found few instances of hunting in low light levels. 

      Imatest showed the lens to be capable of exceeding expectations for the EOS 40D's sensor. Edge softening was slight for such a fast lens. The highest resolutions were recorded between f/4.5 and f/5 but resolution was very good at wider apertures and diffraction didn't produce significant loss of sharpness until about f/8, as shown in the graph of below. 

      Lateral chromatic aberration was negligible to low and we found no coloured fringing in test shots, indicating the value of the SLD glass elements. In the graph of our Imatest tests below, the red line marks the boundary between negligible and low CA values, while the green line separates low from moderate CA.

      Vignetting at maximum apertures was barely noticeable until the 150mm focal length and disappeared when the lens was stopped down to f/4.  We detected slight barrel distortion at 50mm and slight pincushioning at 150mm. Between these extremes, the image field appeared relatively flat. Both aberrations were easily correctable during editing.

      Although it was possible to force the lens to flare, this only happened when bright lights shone directly into the lens. Even then, internal reflections and scattering were relatively low, thanks to effective internal surface coatings and the well-designed lens hood. Shots taken in strong backlighting where the light source was outside the field of view of the lens showed very little loss of contrast and colour fidelity was well maintained. 

      Despite its lack of macro focusing, this lens produced some creditable close-ups of larger flower heads and leaves. The large aperture and long reach created an attractive blurring (bokeh) in out-of-focus areas, even when the lens was stopped down a few notches.

      The OS system provided effective stabilisation across the zoom range and enabled us to shoot with the 150mm focal length using shutter speeds slower than 1/20 second and obtain more than 60% of sharp images. This provided an advantage when shooting close-ups in dimly-lit situations.

      Conclusion
      The camera manufacturers haven't catered well (so far) for users of their APS-C sensor DSLRs who want a fast, medium-range zoom lens for portraiture. Both Canon and Nikon produce significantly cheaper kit lenses with slightly greater magnification, although both have been around for a few years and both have maximum apertures of f/4-5.6. which makes them relatively slow (particularly at the tele end).

      The Tokina AT-X 535 Pro DX AF 50-135mm f/2.8 has a slightly shorter zoom range but matches the Sigma's f/2.8 maximum aperture. It's also slightly smaller and lighter but its price tag is similar to the Sigma's. It's only offered in Canon and Nikon mounts.

      The size, weight and large lens hood, make the Sigma APO 50-150mm f/2.8 EX DC OS  HSM an impressive lens for shooting indoor events where low light levels are likely. Photographers using APS-C DSLRs will find its versatility and excellent performance well worth its price tag.

      Buy this lens if:
      - You need a fast, effectively-stabilised lens for portraiture or product photography.
      - You want a zoom lens that can be used with polarisers and graduated filters.
      - You require good flare resistance in backlit situations.

      Don't buy this lens if:
      - You have a camera with a 'full frame' (36 x 24mm) image sensor.
      - You need a small, lightweight lens.

      SPECS

      Picture angle: 27.9 to 9.5 degrees
      Minimum aperture: f/22
      Lens construction: 21 elements in 15 groups
      Lens mounts: Sigma, Nikon, Canon
      Diaphragm Blades: 9 (rounded)
      Focus drive: Hyper Sonic Motor
      Stabilisation: Yes; approximately 4 stops of compensation
      Minimum focus:  80 cm
      Maximum magnification: 1:6.3
      Filter size:  77 mm
      Dimensions (Diameter x L): 86.4 x 197.6 mm
      Weight: 1.34 kg

      TESTS

      Based on JPEG files taken with the Canon EOS 40D.

       

      SAMPLES

      Vignetting at 50mm.

      Vignetting at 70mm.

      Vignetting at 100mm.

      Vignetting at 150mm.

      Rectilinear distortion at 50mm.

      Rectilinear distortion at 70mm.

      Rectilinear distortion at 100mm.

      Rectilinear distortion at 150mm.

      50mm focal length, ISO 200, 1/800 second at f/7.1.

      70mm focal length, ISO 200, 1/800 second at f/7.1.

      100mm focal length, ISO 200, 1/800 second at f/8.

      150mm focal length, ISO 200, 1/800 second at f/8.

      150mm focal length, ISO 200, 1/1000 second at f/8.

      Crop from the above image enlarged to 100% to show the absence of coloured fringing.

      Portrait in indoor window light; 150mm focal length, ISO 200, 1/50 second at f/3.2.

      Close-up; 136mm focal length, ISO 200, 1/640 second at f/8.

      Strong backlighting; 135mm focal length, ISO 200, 1/1600 second at f/5.6.

      Flare; 135mm focal length, ISO 200, 1/1600 second at f/5.6.

      Bokeh; 130mm focal length, ISO 200, 1/160 second at f/5.6.

      Stabilisation test; 150mm focal length, ISO 400, 1/13 second at f/2.8.

      150mm focal length, ISO 200, 1/400 second at f/4.5.

      50mm focal length, ISO 200, 1/400 second at f/11.

      Rating

      RRP: AUD$1299;  US$1650

      • Build: 9.0
      • Handling: 8.5
      • Image quality: 9.0
      • Versatility: 8.5

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