Don’t tell anybody, but a digital camera is really a computer that takes pictures. And like all devices based on the electronics paradigm, digital cameras, from pocketable point and shoots to high-end DSLRs, are subject to Moore’s Law, which states that capacity doubles about every 18 months.
This will come as no great surprise to imaging retailers who are now selling 12 and 14 megapixel compacts and 18MP consumer DSLRs, with 1080p HD video capability, but this seemingly inexorable law of motion has other important consequences for memory card manufacturers and camera stores.
To state it succinctly, memory card makers are engaged in a furious battle to provide cards with greater storage capacity and faster write speeds than anybody dreamed possible a year or two ago. Just as important, savvy retailers now realize that such cards are big-ticket items that can well spell the difference between sustainable profitability and squeaking by.
To bring you up to speed on this rapidly evolving technology, we’ve gathered the pertinent facts about high-speed, high-capacity memory cards and hereby present them, along with a selection of the latest products in this category.
Storage Capacity: Bigger Is Better, and More Profitable
The storage capacity of a memory card is generally given in gigabytes (GB) these days, and the number in front of the GB determines the number of images (or the recording time of movie files) the card can hold before the dreaded “Card Full” message flashes on the LCD. For example, since 1GB equals 1,000 megabytes, if you shoot RAW files of around 24.5MB each with an 18MP DSLR, you can store about 650 full-res images on a 16GB card.
The higher resolution (MP) ratings of today’s cameras, including camcorders, is the reason why 16GB is now considered the threshold of “high capacity” and 32GB, 64GB and even larger capacity cards are now very popular with pros and serious enthusiasts who tend to use higher res cameras and shoot more pictures.
It’s also an underlying factor that has ignited the memory card speed race—because the more capacity you’ve got the more important a higher throughput rate becomes, especially if you want to shoot extended bursts at 5 fps and faster, or record longer HD video clips without the camera shutting down, corrupting the files or taking forever to display them. Of course, the camera itself, and its buffer, must be able to take advantage of super-speed cards, but in general, camera technology is busy keeping pace with card technology. And this is all the more reason to sell your customers the latest cameras along with high-capacity, high-speed, high-margin cards.
SD Speed Class Ratings: More Megabytes per Second
The speed class rating of Secure Digital cards, the official basic unit of speed measurement defined by the SD Card Association, is defined as 8 megabits per sec, which is equivalent to 1 megabyte/sec, and all minimum write speeds are “based on the best fragmented state where no memory unit is occupied.” Since 8 megabits equals 1MB, a Class 2 card is rated at 16 megabits per sec, or a throughput rate of 2MB/sec; Class 4 cards can record at 4MB/sec; Class 6 to 6MB/sec; and the new Class 10 to 10MB/sec. Pay close attention to the units specified, since a megabit speed rating may seem faster than it really is.
While the class ratings listed by manufacturers are important, they aren’t generally verified by independent tests, so they may not always be attainable in devices that require sustained write throughput, such as video camcorders. If the actual write speed falls below the speed required by, say, a camcorder or a DSLR in HD video mode, the recording could suffer dropouts or corrupted video. The good news is that in many cases the camera can warn the user if an inappropriate card is inserted or if the card’s reported rate falls below the application’s requirements. Obviously, one way to obviate potential problems like this is to buy (or sell) a card having a higher speed rating than the minimum required—more expensive, but well worth it for critical applications.
X Ratings: Racing Throughput Speeds
Before there were speed class ratings there were numerical x ratings, still the most common system used for CompactFlash cards and also used by some brands of SD cards. Basically 1x is equivalent to 1.2 megabits per sec, the same speed as a standard CD-ROM drive. This is equivalent to a throughput rate of 155 kilobits per second (Kb/sec). It follows that a 100x card would have a theoretical maximum throughput rate of about 15MB/sec and one of the top-of-the-line 400x Ultra or Pro cards now on the market can save data at the impressive rate of 65MB/sec.
In short, to convert a numerical x rating into MB/sec, multiply the rated speed number by 155,000 and convert the result to megabytes by moving the decimal point six places to the left. If you think 62MB/sec is fast, consider that one of the new SDXC cards is rated at 625x. That works out to a blistering 97MB/sec—holy-moley, Captain Marvel, and it gets better!
Of course, if cards get even faster, everything from the cameras and processors to the card readers and data transfer protocols, and maybe even the internal computer RAM, may have to be updated to handle this amount of data at warp speeds. And Wi-Fi might have to be upgraded as well. Will all this require more current draw (read shorter battery life or bigger batteries), and will it generate enough heat to require countermeasures? As they say, time will tell.
SDXC: It’s Bigger and Faster, but You Could Lose It!
The Secure Digital eXtended Capacity (SDXC) format, launched at CES in January 2009, has its maximum capacity defined as 2TB (that’s terabytes, friend!), equivalent to 2,048GB. Older SDHC cards have a similar theoretical capacity but are limited to 32GB by the SD 2.0 specification.
The initial run of SDXC cards adheres to the SD 3.0 standard that still specifies the FAT32 file system. That limits its capacity and speed to a mere 104GB/sec (also known as UHS104 speeds). Forthcoming SDXC cards are expected to conform to SD 4.0 protocol that uses the exFAT (Extended File Allocation Table) file system that reportedly has the inherent capacity to attain read/write speeds up to 300MB per sec!
Is there a downside to all of this? Yes, and it can be stated in two scary words—compatibility issues. In the above-mentioned SD 3.0 spec, the electronic interface of SDHC and SDXC cards is the same, and the decision to label cards with a greater capacity than 32GB as SDXC is due solely to the limitations in certain versions of Microsoft Windows. However, SDHC devices, including cameras, will
not recognize SDXC cards that use the faster SD 4.0 system. And whatever you do, don’t format an SDXC card in a non-SDXC device such as a computer.
Once an SDXC card has been improperly formatted in a non-compatible device, essentially it is no longer an SDXC card and that indeed is a problem if you shelled out $300 or more for the sucker. Early adopters and retailers beware! Fortunately, SDXC devices are backward compatible with SD/SDHC cards, but the reverse is definitely not the case.
THE LATEST HIGH-CAPACITY
HIGH-SPEED CARDS
Now that you have a high-tech overview of what’s up in memory card land, here’s a quick rundown of some of the coolest high-capacity high-speed memory cards that have recently been introduced by top companies in the field.
Delkin Devices CombatFlash Card. Providing speeds up to 625x (91MB/sec) and manufactured with high-grade NAND flash and an advanced controller design, Delkin’s CombatFlash line includes the built-in Error Correction Code (ECC) claimed to detect and correct errors on the fly. They’re compliant with UDMA mode 6 and come in capacities from 4GB to 32GB. MSRPs: $84.99–$329.99. delkin.com
Kingston Technology 64GB SDXC UHS-1 Class 10 Card. With a minimum data transfer rate of 60MB/sec read and 35MB/sec write, it’s compliant with the SD Card Association 3.01 spec and uses the exFAT file system. It’s compatible with Windows 7, Vista SP1 or later, and XP SP2 or later with an exFAT update. $499. kingston.com
Eye-Fi Pro X2 Card. This 8GB card provides Class 6 read/write speeds (6MB/sec), RAW uploads, endless memory mode, geotagging and, of course, wireless upload via Wi-Fi networks when used with Wi-Fi enabled cameras. As soon as photos are uploaded, Eye-Fi is claimed to make room on your memory card—even if you’re out of Wi-Fi range. $149.99. eye-fi
Lexar Professional 600x & 300x CF Cards. With guaranteed sustained write speeds of 90MB/sec and 45MB/sec, respectively, these 32GB CompactFlash cards are aimed at power users of high-end DSLR cameras. 600x, $499.99; 300x, $249.99. lexar.com
SanDisk 64GB Ultra SDXC Card. Manufactured to SD 3.0 specs, it has a Class 4 speed rating and a read speed up to 15MB/sec. $349.99.
An even faster alternative for SD card users is the 32GB SanDisk Extreme SDHC card with read/write speeds up to 30MB/sec ($388.99). And, the recently announced SanDisk SD WORM (Write Once Read Many) cards are claimed to provide archival, tamperproof storage for 100 years. Aimed at the forensic/scientific market they may attract pros and serious shooters as well. sandisk.com
Sony 32GB Memory Stick PRO-HG Duo. Also offered in smaller capacities, such as 16GB, and developed in cooperation with SanDisk, this new media format uses an enhanced 8-bit parallel interface plus a conventional 4-bit parallel interface to increase interface clock frequency to 60Hz, thus increasing the data transfer speed to an actual rate of 15MB/sec for high-speed and video applications. $249.99. sony.com
Panasonic 48GB & 64GB SDXC Gold Cards. With Class 10 (minimum data transfer rate of 22MB/sec) speed and a “super intelligent controller” optimized for high-end camcorders and other sustained-high-speed operation, these cards are said to include a new technology designed to minimize accidental corruption even if they’re misused. 48GB, $449.95; 64GB, $599.95. panasonic.com
Hoodman Professional RAW CF Card. Claimed to deliver RAW file transfer at 675x or 100MB/sec (15 sec per GB downloads), these UDMA 6 cards are also designed to provide a 500,000-cycle life using SSD (solid state drive) flash inside—more than five times the life of a 90MB/sec card and more than 50 times the life of a typical 60MB/sec card, notes the maker. They’re made in the USA and are said to be super reliable. In capacities from 4GB to 32GB, MSRPs range from $89.99 to $499.99. hoodmanusa.com
PNY Technologies SDXC Cards. Slated for forthcoming release in capacities from 32GB to 2TB with claimed “massive storage at incredible speed,” they will complement PNY’s current line of 4GB to 32GB SDHC Class 4 cards, 4GB to 16GB SDHC Class 6 cards, and 2GB to 16GB microSDHC cards. pny.coms