Power zooms have long been a standard feature on fixed-lens compact cameras, the ultra-zoom models and consumer-level video camcorders, but it’s enjoyed limited success in SLR/D-SLR lenses. Canon once offered a 35-80mm EF-mount powered zoom, but Pentax has been the biggest supporter of the idea and, at one stage, there were seven 35mm-era FA-series lenses with the feature, including a 250-600mm telezoom.

Now with the whole video/still convergence thing and interchangeable lens compact cameras – with their emphasis on speed and smallness – perhaps the accessory power zoom’s time has come. Certainly almost immediately Panasonic had announced its pair of X-series powered zooms for the Lumix G system, Nikon took the wraps off its 1-Nikkor CSC lens line-up and, lo and behold, it includes a power zoom too. It’s hard not to see all the CSC players following suit sooner or later.

As far as video recording is concerned the attraction of a power zoom is that it’s likely to be more consistent in speed than is possible when manually twisting a zooming collar. Nothing looks more amateur than a staccato zooming action. From the CSC perspective, adopting a power zoom instead of the manual control can make for a much more compact lens as is graphically illustrated by Panasonic’s 14-42mm X-Series model. We’re not sure why Panasonic has opted for the ‘X’ designation when the model numbers also include the initials ‘PZ’... why not just call them PZ-series lenses and be done with it? The full titles are unwieldy enough as it is... as in the Lumix G X Vario PZ 
14-42mm f3.5-5.6 ASPH./POWER OIS.

In this case, it’s a model name longer than the product itself! Ironically, the whole idea with the G X-series 14-42mm is that eliminating the manual zooming collar allows for a much more compact lens. It employs a retractable design which is powered rather than manually operated so the barrel extends automatically when the camera is switched on as happens with a fixed-lens compact.

When closed, the barrel length becomes a mere 26.8 mm, but even when it’s fully extended, the power zoom 14-42mm is still a lot shorter than its standard cousin which is 63.6 mm long and weighs in at 165 grams. The G X model is a full 60 grams lighter. In fact, in terms of both looks and size, the X-series 14-42mm power zoom is closer to the Lumix G system’s two ‘pancake’ primes – the 20mm f1.7 and the 14mm f2.5 – which are 25.5 mm and 20.5 mm in length respectively. The PZ 14-42mm also achieves its stunningly compact dimensions via the use of four aspherical elements in its nine-element optical construction which also includes two extra-low dispersion (ED) types. The aspherical elements correct for distortion, the ED glass elements for lateral chromatic aberration. Not surprisingly, the focusing group is internal, and the minimum focusing distance is 
20 cm from 14mm to 20mm and 
30 cm from 21mm to 42 mm.

Panasonic Australia is offering the PZ 14-42mm as one of the ‘kit lens’ options with the Lumix GX-1 which is fully optimised for operation with the power zooms, including zooming via this model’s touch screen control. The G3, GF2, GF3 and GH2 are all compatible with these lenses, but there’s a firmware update (Version 1.1) to enable full functionality which comprises a focal length read-out, stepped zoom operation with preset increments, a resume function (which resets the zoom to the focal length it was at when the camera was switched off) and variable zooming speeds.