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Design

The Sony 18-70mm stands squarely in line with the current kit lens idiom, being a lightweight design of predominantly plastic construction. However it feels reasonably well-made, with the zoom ring in particular unusually smooth and well-damped. Unfortunately it still suffers from the most common kit lens malaise, with a narrow manual focus ring of disappointingly short travel driving a rotating front element, which in turn precludes the use of a petal-type lens hood. Overall it's of much the same ilk as the kit lenses from the 'big two' (Canon and Nikon), whereas those from Pentax and Olympus are rather more nicely designed with proper manual focus rings and superior lens hoods.

On the camera

The lens is a good match to the entry level cameras such as the Alpha 350, but feels a little lightweight on the bulkier Alpha 700 body. The broad zoom ring falls readily to hand, however the manual focus ring simply doesn't work very well due to its short travel; this is especially problematic when coupled with the tiny viewfinders of the Alpha 300 and 350 camera bodies, and on these cameras critical manual focusing becomes practically impossible.

Autofocus

Autofocus is driven by a screw-drive system from the camera body, so AF speed, noise and accuracy is fundamentally dependant on the camera used. On our Alpha 700 and 350 test bodies, we found focusing to be generally fast and accurate under most conditions, although with a certain tendency to struggle a bit in low light, especially at the telephoto end with its slow maximum aperture of F5.6.

Lens body elements

The lens uses Sony's Alpha mount, which is identical to Minolta's A-type. To fit the lens, align the orange dot with that on the camera, and twist clockwise.

The gold contracts are used for communication with the camera, the black metal lever controls the aperture, and autofocus is driven from the camera body via the screw coupler; just over 2 1/4 turns are required to travel from infinity to closest focus.
The filter thread is 55mm, and rotates on focusing; an annoyance for users of filters such as polarisers.

The ALC-SH0006 lens hood attaches via a bayonet fitting directly in front of the manual focus ring. It's a shallow, bowl-shaped hood, of the type which we generally find to be of limited use in either protecting the front element or combating flare.
The zoom ring rotates 100 degrees clockwise from wide to telephoto, with markings at 18, 24, 28, 35, 50 and 70mm. The finely-ribbed rubber grip is a generous 30mm wide, and the zoom action beautifully smooth and precise.

The lens is physically shortest at its 35mm setting and longest at 70mm, with a 16mm extension on zooming between the two. There is practically no play to the lens barrel when extended.
The ribbed plastic focus ring is a mere 3mm wide, and rotates just 45 degrees clockwise from infinity to closest focus. The action is at least reasonably well-damped and precise, but manual focus still seems to have been treated essentially as an afterthought.

The camera will reset the focus position to infinity on mounting the lens, and on power up or down.

Reported aperture vs focal length

Here we show the maximum and minimum apertures reported by the camera at the marked focal lengths.

Focal length 18mm 24mm 28mm 35mm 50mm 70mm
Max aperture
F3.5
F4.0
F4.5
F5.6
F5.6
F5.6
Min aperture
F22
F25
F29
F32
F36
F36
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I had it
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