The JVC GY-HM700U camcorder accepts two SDHC cards. Mary Ellen Dawley
Videotape has faded into the mists of history. The acquisition format of choice for camcorders today is now either hard disk or solid-state "flash" memory, with flash memory pushing hard for the prime spot.
by Bob Kovacs
Both storage types have their advantages, with hard drives taking the lead in storage capacity and flash memory winning out in size, weight and power consumption. The big activity lately is in flash memory, particularly with the new SDXC format now becoming available.
The current generation of SD memory is SDHC (Secure Digital High Capacity), which has a practical upper limit of 32 GB. That's still a hefty amount of memory in a highly compact space, and you can buy a 32 GB SDHC card for $80 or so if you shop around.
What is SDXC? It stands for Secure Digital eXtended Capacity, which theoretically has a maximum capacity of 2 TB-in the same size and shape of a current SD card. Can you imagine 512 GB of storage on something the size of an SD card?
Believe it or not, there is an SD Card Association that develops standards for Secure Digital (SD) card memory, and it has a blueprint for the development of SDcompatible memory, including capacity, speed and size. (There is a microSD card format that is popular with cell phones and MP3 players, and this format is compatible with standard SD memory in much the same way that VHS-C videotape was compatible with the VHS format.) The blueprint for SDXC has standards to take it to 1 TB and possibly beyond.
SanDisk is now shipping its 64 GB SDXC memory card. SD memory cards have been making inroads into professional video equipment for some time and are now common in prosumer video gear, such as the Canon Vixia line of HD camcorders. At a significantly higher level, the JVC GY-HM700U HD camcorder is targeted at broadcasters and high-quality content producers, and it ships with two SD card slots.
Other manufacturers have SD-based acquisition gear targeted squarely at government users, such as the Panasonic AG-HMC150 HD camcorder. Sony now produces professional camcorders that accept SD memory, of which the HXRNX5U is one example.
Some manufacturers have already announced and delivered products that will work with SDXC memory, including Canon's latest Vixia HD camcorder models and all its new PowerShot still-image cameras. Panasonic is making its new still-image cameras compatible with the SDXC format, including some (such as the new Lumix DMCZS7) that can shoot HD video in the AVCHD format.
Some camcorders are addressing the storage issue in a different way: If one flash memory card slot is good, two must be better. Thus, the JVC GYHM700U has two SDHC slots (for a maximum of 64 GB) and the Canon Vixia HF S21 has two SDXC slots.
Panasonic recently announced 48 GB and 64 GB SDXC flash memory cards. Don't get too excited about the possibility of 2 TB SDXC cards for sale at Walmart anytime soon, as 64 GB SDXC cards are just starting to dribble onto the market at prices that will have you wondering what all the fuss is about. For example, SanDisk has its 64 GB SDXC card priced at $350, and it is only available on SanDisk's Web site at the moment. Still, the company sees the sunny side of a new, highercapacity memory product.
"The SDXC card format offers exciting possibilities," said Susan Park, director of retail product marketing for SanDisk. "The card is an ideal complement for recently announced SDXC-compatible cameras and camcorders."
Besides SanDisk, other manufacturers now offering SDXC cards include A-Data, Panasonic and Toshiba. In addition to a 64 GB card, Panasonic has also announced a 48 GB SDXC memory.
Competition among these companies and others should bring prices down but it might take some time. Of course, economies of scale are what will lower the cost of a new technology like SDXC, but it's easy to wonder just how big the market is.
For example, AVCHD (and Panasonic's twin, AVCCAM) is a popular video format for the new class of professional HD camcorders. At its highest data rate of 24 Mbps, a 32 GB memory is good for nearly three hours of record time. If you have a camera with two card slots, that's more than 5.75 hours-certainly enough for a day's shooting and then some.
If you need more record time, it's a no-brainer to bring more 32 GB memory cards, as they are inexpensive, as well as so small and lightweight that it's easy to forget you're carrying them. They're also just about impervious to shock and can withstand a fall over the Grand Canyon without any damage.
HEAD OF THE CLASS
There's another interesting recent development with regard to SD flash memory, one that has to do with speed. Starting with SDHC cards, the data transfer rate of this type of memory has been rated by "Class."
For example, "Class 1" means that the card can transfer data at a minimum rate of 1 Megabyte per second (MBps). SDHC cards that are rated at Class 4 are common and Class 6 can easily handle the data bandwidth needs of any AVCHD or HDV camcorder. After all, a Class 6 card can transfer data at the rate of 6 MBps, which equals 48 megabits per second (Mbps).
Class 10 cards are now available in both SDHC and SDXC varieties, with a minimum data transfer rate of 80 Mbps. With that amount of bandwidth available, as well as the increased storage capability of SDXC cards, will manufacturers create new compression algorithms that offer higher quality and gentler compression?
History demonstrates that they will. That means that a 64 GB flash memory now good for nearly six hours at AVCHD's highest data rate will shrink to perhaps three hours once "AVCHD-Plus" is developed.
The move to solid-state flash memory, often built into camcorders and therefore always available, has driven a minor revolution in camcorder design and production workflow. Flash memory is small, so cameras can be smaller. Flash memory uses less power than mechanical drives, so batteries can be smaller and lighter. Slip a flash memory card into your computer's card reader and the files are right there, reading for editing.
The development of SDXC memory, with its larger capacity and faster speed, is another step in the revolution. Manufacturers want to be seen as innovative, so you can expect announcements regarding compatibility with SDXC.
"The pace of new camera model introduction supporting the SDXC format is accelerating," said SanDisk's Susan Park.
As the latest iteration of the popular SD flash memory format, SDXC will almost certainly be going mainstream in the next year. Since nature abhors a vacuum, manufacturers will figure out ways to fill all those empty bits, and some of them will be highly desirable.