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Pentax Optio RZ18 review: Pentax Optio RZ18

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The Good Sharp images; Good colours.

The Bad Some light spread on sharp contrasts; Poor choice of build materials.

The Bottom Line Ignore the low-tech case, the clicky buttons and the slightly grainy back screen and focus instead on the great results you can get from this mid-priced superzoom. The Pentax Optio RZ18 really is much better than its build quality suggests, and keenly priced too.

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7.5 Overall

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Ultra-compact, ultra-zoom is how Pentax describes the RZ18. While we're not so sure about the ultra-compact bit -- it's larger than the Canon IXUS 230 HS and Casio Exilim ZS10, roughly matching the size of a box of cigarettes -- we're right on board with the latter.

Packing one of the longest zooms currently available on a pocketable camera, at 18x zoom, the RZ18 tops much of the competition. It is keenly priced at £160.

Build and design

Build quality is good but not great. The RZ18's body is entirely swathed in cheap-feeling black, white or orange plastic and there's clearly some space behind the finger grip. It flexes slightly when pressed and sounds hollow when tapped.

The flash is positioned directly above this rather than to the right of the lens, which is a shame as your fingers can easily get in the way -- as ours did.

Pentax Optio RZ18
The flash could be better positioned as our chubby fingers often obscured it.

Shot-to-shot time is a slow 5 seconds when using the flash and around 2 seconds when it's switched off. Both of these times are too slow for our liking.

Around the back, the buttons are clicky and tacky. They're well laid out and easy enough to use, but they're unrefined and unresponsive. They don't sit well on a camera that costs upwards of £160. The screen has a slightly coarse grain and when framing subjects that aren't brilliantly lit -- under regular indoor lighting, for example -- there's some noise in the on-screen picture. The menus look dated too.

Stills performance

What really matters though is how it performs. Here it did rather well. We have no complaints where handling is concerned. There's an 18x zoom, equivalent to 25-450mm in a regular 35mm camera. It's both quick to find its position and fast to focus when you half-press the shutter release. It's not overly noisy, so you can use it fairly discreetly.

We set the RZ18 to its maximum 16-megapixel resolution, using auto picture mode so that it could choose the best settings throughout our tests.

It consistently impressed us with accurate colours and sharp images at all levels of zoom. The RZ18 did a good job of working with lower levels of available light, keeping its sensitivity at the bottom end of its ISO 80 to ISO 6,400 range.

Pentax Optio RZ18 colour test
The Pentax Optio RZ18 did a great job of capturing vibrant colours throughout our still image tests (click image to enlarge).

Its macro mode, which tops out at 4cm, is quick to get a fix and renders plenty of detail. Even with a fairly narrow palette, such as the teasel head below, it picks out not only the spines but the smaller teeth on each one against the darker interior; it does this while throwing the background out of focus, thanks to its self-selected aperture of f/3.5 -- its maximum at full wide-angle. When zoomed to 18x, the maximum aperture narrows to f/5.9.

Pentax Optio RZ18 macro test
The RZ18 captured a high level of detail in this macro test image (click image to enlarge).

The RZ18 consistently impressed us with the sharpness and clarity of its results, particularly when shooting complex scenes. The shot below of a tree full of red leaves has a lot of fine detail in the foliage, with a definite sweet spot in the centre of the frame where the focus is particularly sharp. The areas behind and ahead of this are both slightly blurred due to the fairly wide aperture of f/4.4, drawing the eye in to the centre of the frame.

Pentax Optio RZ18 detail test
Despite the very complex scene, the RZ18 captured it cleanly and in great detail (click image to enlarge).

However, where it encountered strong contrasts, its performance was less impressive. The RZ18 initially fired the flash when shooting the image of a tree below, where we were looking directly up into the canopy. This was despite the fact that, as can be seen from the image, there was plenty of light in the scene. It was actually the second time we'd tried to manually suppress the flash.

Surprisingly, when the flash was switched off, the RZ18 actually knocked down its sensitivity from ISO 600 to ISO 500, without introducing a great deal of noise; it slowed the shutter slightly (from 1/60 to 1/50-second) to compensate. The full range of shutter speeds stretches from 1/2,000-second to an unimpressive 1/4-second in all but night scene mode, which extends it to a more respectable -- although still conservative -- 4 seconds.

Pentax Optio RZ18 detail test
Detail was lost where the needles on the branches of this tree meet the bright, overcast sky (click image to enlarge).

The wood is well rendered and there's plenty of detail in the pine needles. But where these meet the areas of overcast sky visible between the branches, we noticed that the image suffered from a loss of detail. This had also been evident in the version of this shot captured while using the flash.

This loss of detail, where finer parts of an image passed in front of an overcast background, occurred frequently during our outdoor tests as the light encroached on the darker elements.

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