--- Fred <[EMAIL PROTECTED]> wrote:
> > and uses SecureDigital cards rather than CompactFlash cards
>
> Please pardon my ignorance here (since I'm not yet a DSLR
> user), but:
>
> 1. Which is the more commonly used type of card on DSLR's, in
> general?
CompactFlash is the most commonly used card today. It was the
first flash-memory card type standardized, based on PCMCIA/PC
Card and CardBus hardware protocol standards, and has been in
the field longer than any of the others.
> 2. Are there any technical and/or functional advantages of
> one type of card over the other?
There aren't many differences in function.
SecureDigital cards were designed with much the same ideas in
mind that MultiMedia card and Memory Stick card formats were: to
make the cards smaller, allowing more compact devices through
smaller/more compact reader assemblies; to make the cards more
robust and easier to handle through lack of fine gauge pin
connections and a springloaded/push-push reader locking
mechanism; and to provide a hardware write lock switch. SD and
Memory Stick cards were also designed to have features salient
to authentication features deemed necessary for commercial music
providers, but these are irrelevant for the users of digital
cameras.
At first, SD media cards were relatively expensive for their
capacity and were limited to a 1.5Mbyte per second IO speed, but
that's changed rapidly as more manufacturers have adopted the
format, creating a much larger market, and as the card
manufacturers have competed on capacity and speed. Now, SD cards
are on par with CF in terms of speed (both are much faster than
nearly any digital still camera hardware is able to take
advantage of), and only a small differential exists between CF
and SD cards of similar capacity and performance spec. SD card
slots are noted for higher reliability because of their simpler
and self-cleaning connector design: no fine-gauge pins to bend,
more flexibility with 'approach angle'.
Currently SD and CF are the most widespread flash media cards in
the business, I'm not sure which is gaining ground more quickly
but it seemed that a few months ago SD was eclipsing CF in most
new products, due primarily to the smaller form factor. SD cards
with 2Gbyte capacity and high speed data rates will be available
within a month or so, there are several vendors already taking
pre-orders for 2G Sandisk Ultra II and ATP 60x cards. 4G and 8G
prototypes are also rumored to be right around the corner.
In the end, storage media is simply a commodity that gets
cheaper every year. I have cameras that use Memory Stick, CF,
and SD ... Yea, it cost a bit a couple of years ago to acquired
adequate storage to be useful, but now with inexpensive 1G
high-performance cards easily available, it's not something to
worry about too much unless you require one memory format for a
large number of devices.
However, if you're specifically in need of a system camera
backup, it only makes sense to buy a backup that uses the exact
same storage, battery and accessories as your primary camera.
Godfrey
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