At last weeks Broadcast Asia trade show in Singapore, Sony revealed that they are working on a new highly compact XDCAM camcorder. They showed a prototype camera that was under a glass cover (which was a working unit).
Very few details are available at this time. The camera shown appears to be based on either the Sony AX100 4K camcorder or the similar CX900 HD camcorder. These both use a 1″, 20MP CMOS sensor that produces really rather good images (although it does suffer from a fair bit of skew/rolling shutter) and have 8 bit XAVC-S recording to SDXC or SDHC cards in 4K and HD in the AX100 and HD only in the CX900. This new camcorder will be able to record using 10 bit 422 XAVC long GoP, probably at 50Mb/s like the new PXW-X180. Whether it will also be able to record the XDCAM Mpeg2 codec is less clear, personally I suspect not.
This camera follows on from the Sony tradition of taking a top end compact consumer model, tweaking the recording codecs, adding a few more pro style features and adding an XLR input. So it’s no surprise to see this really. Given the great images from the CX900 and AX100 I would imagine that this new camcorder will pack quite a punch for such a small unit. The AX100/CX900 have a 12x optical zoom with image stabilisation and the ability to digitally increase the zoom range to 18x in 4K(AX100) and 24x in HD with very little loss of image quality.
EDIT: I Note that 1: There are no 4K badges on the camera body as the AX100 has. 2: The zoom range is noted as 24x on the camera body. This makes me suspect that this camera will be HD only.
Here are some pictures of the unit shown in Singapore.
Considering that 8-bit 4:2:0 4K XAVC S has a data rate of 60 Mbps, it’s hard to imagine that 10-bit 4:2:2 4K XAVC would have a 50-Mbps data rate. Most likely it is somewhere around 150 Mbps.
The bit rate for the 4K XAVC-S is 60Mbps, the bit rate for HD XAVC-S is 50Mbps and the bitrate for 10bit 422 XAVC Long GoP IS 50Mbps (see PXW-X180 etc). The bit rate for 10 bit 422 XAVC I-frame is only 100Mbps in HD.
You cannot possibly record 150Mbps to SDXC cards, the limit is around 70Mbps so there is no way this camera is likely to go above the 60Mbps of 4K XAVC-S.
But given that the bit rate for 4K XAVC S is 60 Mbps for 8 bits vs 10 and 4:2:0 vs 4:2:2, it’s unlikely that 4K (as I mentioned) 10-bit 4:2:2 long-GOP XAVC will have a lower bit rate (i.e., 50 Mbps). In any case, I’ve never seen any published figure for it (and in fact Sony has been pretty vague about that flavor of XAVC). Therefore, if the 10-bit 4:2:2 long-GOP is indeed limited to 50 Mbps, the camera probably doesn’t record 4K, at least not in that format.
Unless I’m mistaken, the UHS-I/II class 3 defines a 30-MBps — that’s megabytes per second — or 240-Mbps constant minimum write speed. UHS-I/II class 3 cards were developed for 4K recording.
If you bothered to read the article, I was talking about HD “50Mbps like the PXW-X180” – an HD only camera. The HD rates are already published (see PXW-X180), so the rates for HD will be 50/35/25Mbps.
We do not know for certain yet whether this camera will do 4K or not, if it does, it will probably be limited to XAVC-S due to the media restrictions. I suspect this camera will be HD only as there are no 4K badges on the camera body and the electronic zoom is labelled as 24x, which is the same spec as the HD only XC900.
UHS card speeds are interesting. I note Lexar’s maximum write speed is now 90MB/s for their Pro SDXC cards, but they also state a guaranteed minimum write speed of 10MB/s (80Mbps). The minimum write speed is important as this is the speed the card may slow down to when getting full or when the data write pattern is not sequential. While you might be able to hit a peak of 240MBps, sustained writing of video clips and metadata requires a huge overhead of at least 300% for reliable recording as the write is not completely sequential but in very rapid bursts which puts a lot of extra stress on the card. There are plenty of tests of this that show that as they start to fill up, high end SDXC cards will max out at between 80Mbps and 120Mbps with a typical video plus metadata write. Plus you never want to be too close to those limits, as for a pro camera your recordings must be 100% reliable.
Sony have already made it clear with the PXW range of cameras that they will not currently support bit rates as high as 100Mbps to SDXC, limiting the maximum rate for the current XDCAM cameras to SDXC at 50Mbps. You cannot record HD XAVC-I or any other codec above 50Mbps to SDXC on the the PXW-X160 or PXW-X180, so it is almost certain that this camera will have the same restriction.
I did read the article, and because you referred to the AX100 several times, it wasn’t clear you were talking about HD only. As no camera yet that I’m aware of has 4K long-GOP 10-bit 4:2:2 XAVC (although in their literature Sony implies this could happen) and it wasn’t originally clear that you thought the new camera was HD only, I inferred that if it did have 4K, its long-GOP XAVC would have the same bit rate as a known implementation, that of the X180, which I’m aware is HD only. Your edit cleared up the confusion.
As far as I’m aware, UHS card speed classes are minimum sustained write speeds. The base speed (class 1) is 10 MBps, and class 3 is three times that. So a UHS class 3 card can record at a sustained rate of 30 MBps (240 Mbps).
The PMW-Z100 4K camcorder currently records XAVC intra frame 422 10 bit at close to 600Mbps to XQD cards. The FDR-AX1 records XAVC-S 420 Long GOP 8 bit at 60P 150Mbps , lowest 30P at 50Mbps to XQD cards. Both are rumored to get a firmware upgrade this summer ( at least I look forward to that on my AX1 !!! ) I expect a 30fps 4K version of 10bit 422 Long GOP will be closer to the specs on the AX1 for data rates. My guess about 100Mbps.
Ron Evans
This looks the same as the new X70 , do you know what the difference is ?