Lytro, the company whose light field camera technology promised much but ultimately disappointed with its first camera, is back with a more professional-level camera.

The Lytro Illum is a $1,600 (around £950) camera that, much like its cheaper predecessor, captures data on millions of rays of light, including their color, intensity and direction. This allows users to refocus their photos after the shot is taken.

The difference this time is that the Illum looks like an actual DSLR camera, rather than the box-shaped design of the original Lytro camera. It has a 30-250mm equivalent focal lens up front, a 4-inch touch screen on the back and a slew of physical controls for things like the shutter, exposure and auto-focus. The mechanical shutter has a speed of 0.25 milliseconds, according to Engadget.

The lens is noteworthy, not just for its wide variable focal length (providing 8x optical zoom), but for its constant f/2.0 aperture, which is better than most telephoto lenses, and for its weight of 1.5 pounds. As Engadget points out, a traditional lens with those specs would have to be much heavier, due to the need for additional glass to ensure proper light curvature as it hits the sensor. Because Lytro's sensor can detect the intensity and direction of light, it can make the necessary corrections through software, and use fewer pieces of glass in the lens. Of course, the flip side is that Lytro has to cover many usage scenarios with a single lens, since it's not interchangeable.

You can see the Lytro Illum in action in the company's trailer (below).

As with the original, the Lytro Illum's main trick is its ability to create interactive photos, in which users can change the focus on an existing shot. To help out, the Illum's screen offers a depth assist overlay, effectively telling users how much of the image will fall into the refocusing range. Additionally, a new type of Lytro image can animate the refocus effect as it's happening.

Lytro may be right to target the high-end market, considering that several smartphone cameras now offer similar refocusing features, either through hardware (as with the new HTC One) or software (as with Nokia's Refocus app and Google Camera's Lens Blur effect.) While these features can't top Lytro's fancy technology, they're good enough for basic use.

The challenge for Lytro will be to convince professional photographers that light field photography is worth the money and the trade-off in versatility compared to a traditional digital SLR.