Sony entered the solid-state arena late last year with it's XDCAM EX format. (Paying attention? That's XDCAM, XDCAM HD and now XDCAM EX). XDCAM EX is currently a solid-state-only format, shooting on a new memory card format called SxS (S-by-S) built on the ExpressCard interface format. It's a bit like the P2 you know, but smaller (physically) and faster, but not currently as widely available -- although if you have a recent MacBook Pro, or a nice new PC laptop, then there's a good chance you'll have a slot).
In looking at XDCAM EX we have three things to look at; the format (Long-GOP 4:2:0 MPEG, the media (ExpressCard high-capacity, high-speed sold-state flash memory) and the camera (the PMW-EX1 fixed-lens small form-factor 3-CMOS camera). So let's begin at the beginning, with the format.
The Format
XDCAM EX builds on XDCAM HD, which in turn builds on HDV. So it's a Long-GOP MPEG-2 codec, with 4:2:0 colour sampling.
For many people there's an immediate aversion to Long-GOP formats, as we associate it with the poor performance of Long-GOP formats like MPEG-2 DVD video where blocking can be immediately seen in fast motion and complex detail. But with more advanced Long-GOP codecs (like HDV, XDCAM HD and now EX) those problems become increasingly rare. Even first generation HDV exhibited very strong performance in trying conditions.
That was first generation, and only 25Mb/s – now we're at least a few generations down the line, and working at datarates around 35Mb/s. Even in trying conditions EX holds up very well.
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However it is a compressed format, and it can be seen if you look for it, but more on that later.
Previously HDV and XDCAM HD have supported thin-raster 1440x1080 video. This is pretty common for HD acquisition. But the EX format introduces support for full-raster 1920x1080, as well as 1280x720. It does this with a 35Mb/s variable bit rate codec (HQ mode in EX terminology).
The Media
Sony and SanDisk teamed up to produce SxS. It has immediate similarities with Panasonic's P2 – the most obvious being that is uses a computer-extension interface (like P2's Cardbus) rather than a memory-specific interface (like SD or Compact Flash). It's a sturdy and largish memory card, not easily lost – a little over half the width of a P2 card, and a little shorter.
SxS being a PCI-Express-based card is capable of very high data transfer rates -- up to 2.5Gbit/s, but limited by physical read/write speed limitations. Sony also plans to license the format to other third-party manufacturers, which should ensure good supply and competitive pricing.
ExpressCard is the replacement for the older Cardbus format. It is now the only external interface on new MacBook Pro notebooks, and many PC laptops. For computers without ExpressCard interfaces, Sony offers a USB reader for the cards, and the EX1 camera can also operate as a USB reader.
Sony has also announced the new PHU-60K, a 60GB hard drive unit designed to interface with the EX3.
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The Cameras
The cameras are the big thing in the XDCAM EX offering. The first offering is the PMW-EX1 - it's a handheld fixed-lens camera, not unlike Sony's own Z1 but it's a huge step up. The camera is branded as part of the Cinealta range alongside Sony's F23 and F900 digital cinema cameras. It features the same gamma curves and has been developed out of that end of the company, rather than the group that gave us the PD150 and Z1.
The most immediately obvious thing about the camera is its lens. It's a Fujinon 14x5.8 lens, featuring real manual zoom and iris rings, but even better than that, a genuine manual focus ring, with distance markings and everything. It's the lens we've always wanted to see on one of these cameras.
Beyond the excellent lens, the camera also features a large and vivid LCD screen, adjustable zoom handle, and an HD-SDI output. It is clear this camera has been designed as a scaled-down professional camera, rather than a scaled up consumer camera. Although the quality of the viewfinder is not great at all, this is probably made up for by the great LCD.
I should point out that it was widely reported that early model EX1 cameras featured a 'vignetting' problem. My friendly Sony rep assures me that the error was very limited and that that serial range of all potentially affected cameras was known. The issue can be corrected in service, but the error is apparently very hard to spot. While my camera is apparently within the range that may possibly be affected, I certainly didn't notice anything out of the ordinary. It seems that this problem is certainly a past issue now.
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But the EX1 looks likely to just be the beginning. Sony recently announced the next camera in the EX lineup. The PMW-EX3 (perhaps the EX2 never quite made it) has features that are very similar to the EX1, but with important differences. Most obviously, it is a little larger and has a physical profile that resembles the Canon XL1.
But beyond that, there are a few big bullet points for this camera. The much-maligned viewfinder is gone. Instead, the much-lauded LCD has become a unique LCD/Viewfinder hybrid. Perhaps the biggest and best feature of the EX3 is the lens. It comes with the same great lens as the EX1, but it comes off. And with a (probably supplied) B4 adapter you can use any existing 1/2” broadcast lens.
The Pros
There are many positive features of the format and the EX1 (and the EX3 when it arrives), but the ones that stand out most are:
*Full Raster* – With the ability to record full 1920x1080 images from a full 1920x1080 native chip, this camera stands alone in its field.
*Record Time* – Even on the basic 8GB cards, the camera will record around 28 minutes of 1080p footage on a single card, or nearly an hour with a 16GB card.
*Lens* – The EX1's lens, despite being a fixed lens, offers full manual control. The EX3 will feature a removable lens and the ability to use professional lenses.
*SDI* – With HD-SDI out the EX cameras offer full resolution monitoring, and also a raw 4:2:2 feed from the camera head for those more demanding situations. (Chroma key springs to mind.)
*Quality* Despite many people's misgivings about Long-GOP codecs, the EX codec seems to perform very well and certainly holds up well under normal conditions.
*Cinealta Gamma* – Eight Cinealta gamma curves provide good options for 'film look' shooting.
*Variable Framerate* – Depending on record mode, the EX1 supports frame rates from 1 to 60fps.
*Card Availability* – While only Sony-made SxS cards are currently supported, Sony assures us that support for third-party cards will be available soon, and increasingly other manufacturers will offer SxS cards after Sony's initial development partner SanDisk).
*New Interface * - The ExpressCard interface on which SxS is built is the new standard for external bus interface, and is increasingly the only extension slot offered in new laptops. It can be easily incorporated to modern desktop computers.
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The Cons
Nothing is perfect, and of course XDCAM EX has its drawbacks. A few are:
*New Format* – This will become less of a problem, but right now the fact that EX is new means that it can be difficult to work with.
*Solid-state* – Generally a benefit, it should also be considered that solid-state recording in general can increase the complexity of production and post-production.
*Ergonomics* – While the EX1 is a very well developed camera, there were a few ergonomic issues that bothered me – most notably the zoom handgrip, which has a bit that digs into my thumb. Many of these issues will cease to be a concern with the EX3.
*Compression* – The relatively low bitrate does mean that compression must be quite heavy. While not visibly obvious, the evidence of compression is certainly there to be seen.
*Color Sampling* – 4:2:0 sampling means that the effective chroma resolution is only half the full frame resolution. However this method does deliver very good results in most situations.
*New Interface* – The ExpressCard interface on which SxS is built is quite new, and certainly not as widely available as the CardBus format.
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The Nitty-Gritty
In general, looking at the footage from the EX1 on a Sony LMD-2450W 1080-native monitor, the images from the camera were very impressive. They look sharp and vibrant and exhibit no obvious motion or compression artifacting, even on rapid movements.
However on close examination of still frames from the transferred images there is clearly some mosquito noise within the frame and on areas of high details and contrast. However in practice this noise is not at all evident in playback or at regular sizes.
One big concern with EX1 (and CMOS cameras in general) is Rolling Shutter. Essentially, because the sensor is read one line at a time, top to bottom, it is possible to have unusual motion or strobe artifacts.
On a fast pan, for example, vertical objects can look slanted because the image as moved horizontally in the time it takes to read from the top to bottom of the sensor. With strobes and flashes the effect is quite different. Depending on the length and timing of the flash the image can appear in only part of the frame. With a strobe light this may result in the lower half of a frame exhibiting the result of the light flash, while the upper half is still dark. Overall the rolling shutter issues are fairly specific and don't tend to have any impact on most shooting situations.
Transfers from the cards, even reading via USB2 from the camera is fast and easy. In a native ExpressCard slot the speeds should be eve quicker. Copying the raw card data from the card to a local hard drive is easy and works well with provided XDCAM management software.
NLE support is still in development, but at present it is supported in Final Cut Pro 6.0.2 (with a Sony-provided transfer tool.
Native support for Avid is not yet available but it's been promised. In the meantime, one crafy EX1 user has found a way to create Avid media from the EX1 files using a freely available opensource tool. The process is detailed on his blog (http://www.bolanski.com/ex/home/ffmpeg-is-your-friend). While this is a useful solution for small numbers of clips, it becomes difficult and ineffective on any larger projects as in converting the media any timecode or metadata connection to the original footage is lost.
Support in Adobe Premiere Pro is available through third-party tool, MainConcept MPEG Pro 3. Canopus Edius Broadcast has native support from version 4.6 onward. Sony's own Vegas Pro also offers native support.
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Working with EX
As far as getting the media into your editing workflow, there are a few options. You can use the camera. It can operate as a USB2 device, visible to your computer as a simple external drive. Or, buy Sony's SBAC-US10 SxS USB2 reader for about $250.
If you've got a modern notebook computer, there's a good chance you have an ExpressCard slot already. If you want to add support to your desktop computer, it is easy an inexpensive assuming you have a PCI-Express slot free – you can pick up a standard PCI-Express to ExpressCard adapter for around $60 which will add an ExpressCard slot to the back of your computer. Or for about $140 you can get front-mounting ExpressCard reader.
If you are purchasing third-party hardware to work with SxS it's important to make sure it supports PCI Express-based ExpressCards, as the SxS cards are not compatible with USB-only ExpressCard hardware.
In Summary...
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XDCAM EX takes the HDV concept a few steps further with a higher bitrate, an improved codec, full 1920x1080 raster and a solid-state acquisition. It implements a MPEG2 4:2:0 Long-GOP codec at 35Mb/s VBR (HQ) or 25Mb/s CBR (SP), and offers resolutions of 1920x1080, 1440x1080 and 1280x720, and supports the full range of framerates in both 50Hz and 60Hz systems
The EX1 camera brings professional lens features to a fixed-lens camera, and captures the image on 1/2” 1920x1080 native CMOS sensors and offers the pedigree of the Sony Cinealta range at a very affordable price. The EX3, due Q3 2008, offers all the same features, with improved ergonomics, a larger form factor and support for interchangeable lenses.
XDCAM EX's SxS memory card format is designed around the most currently external bus interface and offers very highspeed data transfer using a native bus interface. With additional manufacturers licenced to produce the media, it's likely that media cost will drop in the future and help to avoid supply issues.
The XDCAM EX format is a big step in for cameras in this area of the market. The EX1 marks the same sort of big change that other groundbreaking small cameras before it have, including Sony's own VX1000 and PD150.
All footage grabs in this article are courtesy of Lance Wordsworth. |
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