Sony 28-75mm f/2.8 SAM (SAL-2875) - Review / Lab Test
Lens Reviews -
Sony Alpha (Full Format)
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Review by Klaus Schroiff, published July 2011
Special thanks to Dieter Scherk for providing this lens!
The Sony allows itself the luxury to offer two large aperture standard zoom lenses in the Alpha lens lineup. Obviously Sony recognized the need for a cheaper option below the Zeiss ZA T* 24-70mm f/2.8 SSM - the Sony 28-75mm f/2.8 SAM. Its origin is a bit of an open secret. Sony has a stock share in Tamron and guess what ... the 28-75mm f/2.8 SAM has obviously the same optical design as the Tamron AF 28-75mm f/2.8 SP XR Di LD Aspherical [IF]. There are, of course, cosmetical differences in order to match the Sony styling and it offers SAM - Sony's "Smooth Autofocus Motor" thus a micro-motor instead of relying on the AF drive-screw. The Sony lens costs less than half of the Zeiss ZA but they're asking about the double price of the Tamron which seems a little bold regarding the few differences between the two.
The build quality may be good by consumer standards but neither the finish nor the subjective quality of the used materials are comparable to the Zeiss ZA cousin. Both the zoom and focus ring operate quite smoothly. As you may have noticed in the product shots below the lens extends when zooming towards the long end. Thanks to the IF design the lens front does not rotate during zooming or focusing so using a polarizer is no problem.
The AF speed of the SAM (Smooth AF Motor) is quite good but only a shadow of the SSM used in the Zeiss lens. Manual focusing is rather difficult due to the very short focus path. DMF ("Direct Manual Focusing") is NOT supported - this is a limitation of all lenses featuring a SAM.
|Optical construction||16 elements in 14 groups inc. 3 LD elements, 4 aspherical elements and 2 XR elements|
|Number of aperture blades||7 (rounded)|
|min. focus distance||0.38 m (max. magnification ratio ~1:3.9)|
|Dimensions||78 x 94 mm|
|Filter size||67 mm (non-rotating)|
|Other features||Zoom lock (at 28 mm).|