The Alpha a7S is a remarkable technical achievement and a device that could revolutionize how filmmakers and photographers work.

When discussing high-specification pro-focused cameras, it's very easy for the uninitiated to get lost in all of the numbers, and this Sony is no exception. For example its ISO range tops out at 409600. Not only is that way beyond the comprehension of many, it's also way beyond the need of many photographers, even some pros.

What makes this camera special is that it is a mirrorless unit which means it's similar to a DSLR camera but smaller because the mirror that reflects the view from the lens into the viewfinder has been removed.

Taking out this piece of the prism reduces size, saves weight, and eliminates the need for a viewfinder too, as the image is relayed to the digital display instead. However, these smaller units don't leave enough room for a full-frame image sensor, meaning that the pictures aren't quite as good as those captured on a full-sized interchangeable lens camera.

However, not only has Sony somehow made the space for a full-frame 12.2MP Exmor CMOS sensor and BIONZ X image processor in the Alpha a7S, it is also the first such camera capable of shooting 4K (QFHD 3840 x 2160 pixels) video. So it's something that's small enough to just about slip in a pocket but that packs the same punch as a low-budget film production studio.

With the camera, Sony is bringing the same benefits to video professionals that the mirrorless units have already bought to pro stills photographers. Something extremely versatile, lightweight and technically advanced that offers incredible results but won't break the bank.

And not only is there a decent selection of dedicated and adapted lenses available, plus a host of accessories, the camera can output what it's recording to a host of third-party video recorders. Ideal for multi-camera, multi-angle video production or broadcast studio work. And, of course it shoots stills too.

So a world of visual possibilities and all for just $2,500 (for the body; lenses are sold separately) when it goes on sale in July.