Note: All of the new SanDisk SDHC cards--regardless
of the price--are bundled with a free SDHC card reader, a $20 value, suitable
for use with any SD card. The Extreme III series also includes ESP Technology
to streamline data transfer, RescuePRO software to recover accidentally deleted
files, a tech support telephone hotline, and a limited lifetime warranty.
Sony: The primary proponent of the Memory Stick format, Sony
has doubled the storage capacity of the PRO Duo series to 8GB ($299, list).
All Memory Stick PRO Duo media come complete with a Memory Stick adapter for
compatibility with older cameras and card readers. These are very durable cards,
with a temperature range rating of -13ÞF to 185ÞF. Sony is not publishing
speed data at this time, but in 2006, their 4GB cards were rated as 67x; frankly,
they seem much faster than that when used in recent prosumer-level Cyber-shot
Memory Stick PRO Duo
Since the Alpha D-SLRs also accept CompactFlash cards, Sony will start marketing
such cards with 66x and 133x transfer speeds in capacities between 1GB and 4GB.
These products will be branded as part of Sony's Alpha camera system;
price information not yet available.
Alpha 4GB CompactFlash
What's SDHC, And Will It Work With Your Camera?
In practical terms, SDHC cards are compatible only with certain recently built
digital cameras and memory card readers. On the other hand, an SDHC-compliant
camera or other device will work fine with the older SD cards.
In order to determine whether your current equipment is SDHC compatible, check
the detailed specifications on the manufacturers' websites. And if shopping
for new equipment, make sure that it's SDHC compliant if you want to use
the new high-capacity cards. As discussed in this report, some companies provide
a free SDHC compliant (USB 2.0) card reader with certain products, but you can
also buy one for as little as $15.
In order to provide some consistency as to actual speed, the SD Card Association
(an industry standards board) developed new "guaranteed ratings."
These denote the minimum sustained data transfer speed, abbreviated as DTR.
A Class 2 SDHC card provides a DTR of 2MB/sec, a Class 4 card provides a DTR
of 4MB/sec while a Class 6 card provides a DTR of 6MB/sec. Some preliminary
tests have already concluded that some--but not all--SDHC cards can
accept data at a much faster rate. Consequently the SDHC Class rating doesn't
tell you which cards are the fastest but at least it provides a guarantee of
The New UDMA Standard
There's a new standard in CompactFlash cards, too. At least two manufacturers
are marketing cards with a new data timing mode called Ultra Direct Memory Access
(UDMA). That includes the SanDisk Extreme IV series (available since late 2006)
and Lexar's new 300x Pro cards. The UDMA technology is complex, but in
practical terms, it's lightning fast. According to Lexar, their UDMA-enabled
300x Pro card can deliver "a minimum sustained write speed of 43MB/sec"
in a UDMA-compliant camera.
As of this writing, there were no suitable digital cameras; only a few medium
format digital backs were UDMA compliant. With current D-SLRs, the UDMA cards
employ only the slower, conventional (PIO) technology. In unscientific testing
with a Canon EOS Digital Rebel XTi, a preproduction 8GB Lexar 300x card was
very fast, but provided no obvious advantage over my already fast Lexar 133x
cards. We should start seeing UDMA-compliant digital SLRs by the end of 2007
and these will be able to take maximum advantage of the ultrahigh-speed CompactFlash
Note, too, that only a few memory card readers are UDMA compliant. That includes
the SanDisk Extreme FireWire model and two brand-new Lexar Pro models: the UDMA
Dual-Slot USB Reader and the UDMA FireWire 800 Reader. As well, Delkin Devices
makes a CardBus 32 UDMA CompactFlash adapter ($59, list) for Apple and PC laptop
computers for ultra-fast data transfer. (All of those accessories also work
fine with conventional memory cards.)
Manufacturers/Distributors' addresses can be found by visiting the Instant
Links section of our website at: