Sony has this week announced a small XDCAM camcorder with an unusually high specifiation - which will be extended to 4K with a future upgrade
The world contains a lot of small, handheld camcorders. They're often especially small and hand-holdable now we're beyond the point of including a tape mechanism and the only moving part is often in the lens. Sony's new PMW-X70, therefore, enters a crowded field, and needs some genuinely interesting specifications to distinguish itself.
Perhaps the most arresting development in the X70 is the sensor – the same one-inch chip as has already been deployed in the FDR-AX100 and in at least one of Sony's compact stills cameras. This technological convergence is no great surprise, although this is the first time we've seen the sensor married to a 4:2:2 10-bit recording system, which should be as able as anything to demonstrate the successes – and failures, if any – of the imager. The camera has other interesting design features, but before we go into its ergonomic layout or any further numbers, I should point out early on that this article is an analysis of the specification, not a review. I'm reliant on a few minutes' handling of the camera, as well as the test material Sony showed on Monday 28th July at the John Barry Theatre at Pinewood Studios, the complex west of London that's currently hosting production on, among other things, the next Star Wars. The documentary-style material shown did not appear to have been shot in circumstances which would have allowed any kind of problem-obscuring trickery to have been employed, and had been blown up rather unfairly onto an enormous cinema screen, so it's probably a reasonable, if not actually quite trying, test case.
That big sensor gives us, potentially, several things. Photosites on a big chip are bigger, and thus more sensitive and lower in noise, than those on a smaller chip for the same resolution (or, perhaps, the bigger chip can have higher resolution without suffering the problems of small photosites). Depth of field is reduced for a given f-stop, and wide angle is easier to achieve. The X70's sensor does boast a fairly considerable 20-megapixel resolution, which is enough that it can't really claim to have big photosites in the same way that the 12-megapixel A7S stills camera enjoys given its full-frame 35mm sensor. What the X70 does have, however, is lots and lots of excess resolution. This is used in several ways, perhaps most prominently to allow for oversampling of the HD output image. As we discussed recently, oversampling is very nice. It reduces noise and increases sharpness on single-chip cameras, and both characteristics look very good on the X70. The demonstration included a 200% still-frame blowup – I'd have liked to see it move – of the HD output which looked very acceptable, perhaps because of the low noise and high level of natural detail in the frame, without reliance on the edge-enhanced artificial sharpening of other technical approaches.