(Pocket-lint) - The Sony Cyber-shot RX100 III has been announced, boasting a new 24-70mm f/1.8-2.8 (equivalent) lens and new built-in electronic viewfinder. It arrives alongside the original and second-generation RX100 models to sit at the top of the trio as the most fully featured all-in-one compact from the RX-line yet.

Measuring a few centimetres wider than the MkII model, the RX100 MkIII's 101.6 x 58.1 x 41.0mm dimensions maintain the camera's small size despite the boost in features. The new lens means a faster available aperture range throughout, although the top-end focal length is far less than the 100mm equivalent in the older models.

Key to the RX100 M3 is a pop-up 0.39-inch, 1,440k-dot OLED viewfinder. Flick a side-mounted switch and it pops into position from within the body, completed by tugging the rear optic out for it to become a fully functional finder. Very cool.

On the rear the 3-inch, 1,229k-dot WRGB LCD screen is now mounted on a 180-degree tilt-angle bracket. Sony has got in on the selfie craze by enabling the screen to tilt all the way up into a vertical position. But it's still shunned the idea of a touchscreen in the same way the earlier models failed to feature.

Paired with the same 20.1-megapixel 1-inch back-illuminated sensor, the RX100 MkIII adds the latest Bionz X image processor for the ultimate in image quality. Fast autofocus, a built-in neutral density filter and 50Mbps 1080p movie mode add to the burgeoning feature set.

We've been using the Cyber-shot RX100 III ahead of the official announcement. For more detail on what we made of the camera, read our first impressions below:

READ: Hands-on: Sony Cyber-shot RX100 III review

The last part of the puzzle is price and release date. At the time of writing both are unknown, but our Spidey senses suspect a £799 launch price next month. It's a lot of money for a little camera - but don't be fooled by its looks, there's a whole lot of camera tucked into that metal chassis. Sony may just have well introduced the king of the compacts to the market.

Writing by Mike Lowe.