Product ReviewsSony SAL SAL-50F18 50-50mm f/1.8 DT SAM Lens

Crisp image quality, easy to use, but beware of wear in the plastic parts.

Sony have produced a surprisingly good range of cameras and lenses with the Alpha-SLT system. I'm a regular Nikon user, but I've been very agreeably surprised by the still and video picture quality from my Sony Alpha-55, and I was keen to see how a fast aperture prime lens would perform. I've already got the SAM F2.8 30mm Macro prime lens, which works very well indeed, but I wanted to experiment with the shallower depth of field which the F1.8 aperture has to offer, plus a lot more low-light capability than either my existing F2.8 Macro lens, or the F3.5 zoom lens as supplied with the camera kit . The first compromise is that a 50mm lens is not exactly a "standard" focal length with the alpha 55's APS-sized sensor, in fact it's equivalent to a 75mm portrait lens on 35mm film. Sony do offer a prime 35mm F1.8 lens in the same 'budget' range (this corresponds to approx. 52mm 'standard' lens on 35mm film cameras), but it's quite a bit more expensive than the 50mm F1.8 under review here, and I wanted to get the shallow depth of field look without spending too much. So, if you aren't planning to shoot too many room interiors or landscapes which need wide coverage, the 50mm F1.8 looks like the affordable choice. Sony also make a 50mm F1.4 lens, which is 'faster' due to offering a larger maximum aperture, and it offers even less depth of field than the 50mm F1.8. But this is a much more expensive lens (it's from an older Sony range which offers nice features like a solid metal rear lens mount) and more importantly the F1.4 lens doesn't have the SAM built-in auto-focus motor for lightning fast autofocus even in low light. The final other alternative fast prime lens for this camera would be a second-hand Minolta AF 50mm F1.7 lens which, like the Sony F1.4 lens, offers the more durable metal rear mount, but also doesn't not offer the built-in autofocus motor.
So having finally bought the Sony 50mm F1.8 SAM lens, what does it have to offer?
The SAM auto-focus motor gives very fast responding auto-focus action, and in conjunction with the selectable focus zones offered by my Alpha-55 it is able to find focus quickly on those parts of the image you want to focus on. When you switch to manual focus mode, the front mounted rubber focus ring gives smooth and accurate (if slightly noisy) adjustment of focus. All of my Sony Alpha lenses suffer from a noticeable mechanical whine when you turn the focus ring in manual mode, and this noise gets picked up by the on-camera microphone when shooting video. By contrast, my compact system camera is a Sony NEX-C3, and the e-fitting lenses for this little camera are silent in focusing.
The other disadvantage of this range is the use of plastic overall in the construction. The front filter thread is plastic, so you need to take care not to cross-thread when screwing filters into place. Worse still, the rear mounting flange on the lens is plastic, while most other lens ranges offer solid metal mount flanges. So check these areas out before buying a well-used example.
Finally, in use on my camera, it's a total win. Picture quality is excellent across the aperture range, with very good detail reproduction even into the image corners. The lens coating does a very good job of supressing flare, but you may need to use a lens hood when shooting into the light. Out-of focus areas blur very sweetly at wide apertures, giving the professional portrait 'look' I was after, and video focus pulls are easy to do. A great budget buyRead full review...