Nowadays, the smallest mobiles are also often the simplest mobiles. Luxury must-have handsets need to be a certain size to incorporate their sumptuous screens and all their gadgetry.
However, in the still developing world of 3G handsets there is still considerable cachet to being small. After all, if you can't tell from looks and size alone the difference between a 3Ger and a standard GSM model, you'll be more likely to pocket the fuller-functioned 3G model. In the mobile world, size still counts for plenty.
The Z540V is undoubtedly one of the lightest and slimmest 3G phones so far released, tipping the scales at 105g - a shade heavier than Samsung's marginally more svelte Z510 (97g).
On waif-factor alone, it out-slims the Motorola RAZR V3x and the LG U890 but is around the same depth as the metal-coated BenQ-Siemens EF81. The Z540V should also share the prize with the near-identical Z510.
The Z540V is a Vodafone exclusive, geared up for fast access to the Vodafone live! portal for services, downloads and information. Its Z510 stablemate is currently sold by O2, and the main differences is that the Z510 adds a flash, uses rotating optics on the hinge rather than two separate lenses, and puts the external MP3 controls in a different position.
Putting away the measuring tape, the Samsung is an attractive looking piece of kit. It uses the same all black finish that has proved so popular on the D600 and other recent Samsungs - which gives the handset an uncomplicated sophistication.
The exterior screen is more detailed than most. At 128x128 pixels, and with 65,000 colours, it is put to good use for displaying photographic wallpapers, showing MP3 track listings, and as an alternative viewfinder for the camera.
Despite the small size, when you flip open the polycarbonate casing you find a screen that is larger than most. It is a quarter-VGA affair, measuring 320x240 pixels.
This gives a rich viewing experience when looking at stills pictures, and the available picture area is also sensibly used when making video calls - so that you get a good-sized shot of the person you're chatting with, but are still able to see the image that you are yourself transmitting from the secondary camera perched under the main display.
As with an increasing number of clamshell handsets these days, Samsung has provided helpful music player control buttons on the outside of the shell, under the display. This means you can keep the music going - and keep track of what's playing - whether the handset is opened or closed.
Although the phone is designed to facilitate the playing of digital music - whether as MP3, Windows Media, or AAC fi les - it is not designed for those who want to take around a particularly extensive library of sounds.
No card slot
Unlike many other music phones (and megapixel cameraphones, for that matter), Samsung has decided to make do without an expansion card slot. Instead you are provided with a generous inbuilt storage capacity of around 140MB.
This may seem plenty, but you should be aware of how you use this and how much music, for instance, you will be able to store when you have shot a few pictures or mini movies, and built up a collection of downloaded videos you want to keep.
The lack of memory card could also prove inconvenient when transferring files on and off the phone - though you can use Bluetooth or the supplied USB lead for the process, rather than using a card reader.
Listening to music through the built-in speakers isn't the best way to do justice to your favourite tracks - this facility provides a harsh, tinny sound. You can avoid this by using the supplied stereo headset which plugs in with a proprietary connector to the side of the phone.
Sound quality from the earbuds is fair but lacks the frequency response and detailing to give a virtuoso performance. Unfortunately, there are no equaliser controls to tweak the output to your own liking.
Whilst the camera used for self-portraits and videocalling is a simple VGA arrangement, the lens positioned on the outside of the shell is a 1.3- megapixel affair. The resolution that this offers, on paper, is not particularly impressive compared with some of its immediate rivals (the RAZR V3x and BenQ-Siemens EF81 both offer 2 million pixels).
In practice, however, the Z540V delivers superb pictures, which are undoubtedly better than those of some cameraphones with more pixels on their spec sheets. Close-ups are surprisingly good despite the lack of focus controls, providing a readable digital image of an A4 sheet of type.
The skintones in portrait pictures were natural looking and detailed. Even the lowlight performance of the camera was reasonable. And you get a decent number of manual controls and fun effects to play around with.
As you'd probably expect, video recording and playback is also part of the specification, and the phone supports Vodafone's excellent Mobile TV service, as well as other video download and streaming services.
The Samsung handles these adequately but the received image only occupies a small area in the centre of the screen. Unlike with many other handsets, there is no way to blow up the image so that it occupies the whole of the LCD area.
We were impressed by the power management inside the Z540. The phone's battery managed to keep running for 90 hours during which we listened to around half an hour's music, and did about the same amount of TV channel surfing. This is a very respectable performance for a 3G phone - particularly one that is so light.
The overall size of this handset makes this a very appealing phone - 3G or not. Like the more conventionally shaped Z500 before it, the Samsung Z540 is yet further proof that you no longer have to carry around a brick in order to access the latest range of mobile multimedia services.
This phone may not give the best performance of the audio material and video broadcasts that it is capable of downloading. But as a first model for those dipping their tentative toes into the world of 3G it is still a handset that's worth considering. Chris George
Music control buttons: A set of buttons under the display enable the MP3 player to be controlled when closed
Megapixel camera: A 1.3- megapixel camera sits on the outside of the clamshell, above the display
Second camera: Inside the shell there's a secondary VGA camera for face-to-face video calling
Slimline design: One of the thinnest 3G phones around, you'd be hard-pressed to guess it was a UMTS phone