Pentax and Samsung enjoy a 'technology partnership' in the digital SLR market, so it shouldn't be too much of a surprise to discover that there are plenty of similarities between their cameras.

With the Samsung GX20, though, it goes a little further than that. It clearly has the same body, lens, sensor and exterior controls as the Pentax K20D (albeit with a few minor cosmetic tweaks) and, really, it's more or less the same camera.

Samsung or Pentax?

Although Samsung distributes its own branded lenses, for example, these are clearly duplicates of Pentax optics - just as the 18-55mm kit lens on the GX20 is the same as the 18-55mm zoom supplied with the K20D. Indeed, in the Samsung manual it specifies the lens mount as 'Pentax KAF2'.

So who's going to buy a Samsung when they can get a Pentax instead? That's the question most traditional photographers will ask, but it's important to remember that there's a whole new generation of users reared on consumer electronics brands rather than the hidebound world of conventional photographic tradition and, for these users, the Samsung name is likely to be a much more familiar one than Pentax.

Spot the difference

So is the GX20 really the same as the K20D? Not quite. Apart from the badges, the design of the buttons and the look of the menu system (which does actually look a bit smarter than the Pentax's), there are a couple of other more significant differences.

Interestingly, Samsung does claim a longer battery life - 800 shots in the GX20 versus 530 in the K20D. Apart from that, though, the sensor is the same, and so is the overall 'look' of the images.

But while Samsung's promotional literature makes much of the sensor's dynamic range, there was no sign of the expanded dynamic range option that's included on the K20D, either on the ISO screen, in the menus or in the manual.

A pity, because that's one of the K20D's strong points. The list of picture styles on the GX20 is shorter and, surprisingly, there seems to be no Mono mode - on the K20D, you can shoot in black and white and apply different 'digital filters' to simulate a yellow filter, orange filter, blue filter, green filter and so on.

Superb stabilisation

Otherwise, the GX20 has all the qualities that make the K20D so appealing. It's neither light nor compact, but for photographers tired of the cramped handling of cameras such as the Nikon D60 and Canon EOS 400D, that's probably no bad thing.

Twin control wheels make light work of shutter speed and aperture adjustments, and the sensor-shift, anti-shake system enables you to capture sharp shots up to four shutter speeds slower than usual.

And this remains the best of any of the sensor-based stabilisation systems on the market.

Tough camera

The GX20's viewfinder is a good size, but day-to-day operation is let down by the graunchy action of the 18-55mm kit lens. It focuses reasonably quickly, but with a roughness that's quite off-putting compared to the wonderfully super-smooth AF of Nikon and Canon lenses.

Now and again, we also found it to suffer momentary hesitation in 'difficult' conditions (close-ups, or when there are near and distant objects under the same focusing point).

Like the K20D, the GX20 is a tough, solid camera that here and there feels a bit cruder than you might be expecting in a modern DSLR.

Interesting features

It's aimed at enthusiasts rather than beginners, too, so there are no scene modes on the mode dial. But there are two additional 'Sv' and 'TAv' modes, which are also found on the Pentax. 'Sv' is the Sensitivity Priority mode.

You set the ISO that you think is suitable for the conditions and the camera then sets the shutter speed and aperture. In 'TAv' mode, you choose the shutter speed and aperture settings you want, and the camera chooses the ISO needed to get the correct exposure.

Are these useful? Well, they are unique, so it may be a while before photographers figure out what to do with them. They're both interesting ideas, though, which would certainly be worth experimenting with.

Kit lens blues

The characteristics of the GX20's images are similar to those of the Pentax K20D, with good contrast and really strong, saturated colours.

Its images have the film-like intensity that separates the latest generation of DSLRs from what's gone before (more so than any increase in definition). The Samsung's greens are particularly strong, which will please nature photographers.

But the kit lens is a let-down. It's about as sharp as you'd expect in the centre of the frame, but the definition does fall off towards the edges. The noisy, coarse-feeling AF is hardly endearing, either. It also looks a bit odd because it's a small lens fitted to a big camera.

If you're seriously considering the GX20, you might want to think about the new 18-250mm lens as an alternative, or the rather good Pentax 18-50mm f/2.8. Both are much more expensive than the kit zoom, but much more suited to this camera's capabilities.

Competitive prices

Since we're talking money, we inevitably have to compare the Samsung GX20 with the Pentax K20D. Both are selling for around the same money at the moment, though Samsung is offering a £100 cashback deal on the GX20 18-55mm kit until the end of July.

This price tag is attractive, but it's not the whole story. To get the best from a camera of this stature, you really do need a better lens than the one supplied.

To an extent this is true with all sub-£1,000 SLRs, but here it's particularly obvious. The 18-55mm lens will get you started, and it's a good deal financially, but it won't be long before you figure out that both you and the camera need something better.

Thanks to the current cashback deal, the GX20 is a cheaper, if slightly less desirable alternative to the Pentax K20D. Putting that deal aside, though, the K20D is the better camera.