SD/MMC and CF cards for Digital Cameras

[Freehold Fred]

Help me out on this one:

Does SD = Secure Digital?
MMC = Multimedia

Are they compatible?

What ever happened to CF (Compact Flash)? Is it compatible with the above?

[Terry Hanushek]

Being curious myself, I got the following definition from whatis.com. The seem to perform a similar function but with different specifications. It is unlikely that they are interchangeable (that would be too easy.) It also seems like is is another VHS / Betamax thing.

Terry

http://searchstorage.techtarget.com/sDefinition/0,,sid5_gci837971,00.html

http://media.techtarget.com/digitalguide/images/Misc/sdef_definition.gif - A Secure Digital (SD) card is a tiny memory card (http://searchstorage.techtarget.com/sDefinition/0,,sid5_gci836184,00.html) used to make storage portable among various devices, such as car navigation systems, cellular phones, eBook (http://searchmobilecomputing.techtarget.com/sDefinition/0,,sid40_gci492555,00.html)s, PDA (http://searchmobilecomputing.techtarget.com/sDefinition/0,,sid40_gci214287,00.html)s, smartphone (http://searchmobilecomputing.techtarget.com/sDefinition/0,,sid40_gci330613,00.html)s, digital camera (http://searchmobilecomputing.techtarget.com/sDefinition/0,,sid40_gci211950,00.html)s, music players, camcorder (http://searchmobilecomputing.techtarget.com/sDefinition/0,,sid40_gci283966,00.html)s, and personal computers. An SD card features a high data transfer rate (http://searchvoip.techtarget.com/sDefinition/0,,sid66_gci213492,00.html) and low battery consumption, both primary considerations for portable devices. It uses flash memory (http://searchstorage.techtarget.com/sDefinition/0,,sid5_gci212130,00.html) to provide nonvolatile storage (http://searchstorage.techtarget.com/sDefinition/0,,sid5_gci212679,00.html), which means that a power source is not required to retain stored data.


An SD card is about the size of a postage stamp and weighs approximately two grams. It is similar in size to a MultiMediaCard (http://searchsmb.techtarget.com/sDefinition/0,,sid44_gci837119,00.html), but smaller than older memory card types such as the SmartMedia (http://searchstorage.techtarget.com/sDefinition/0,,sid5_gci837127,00.html) card and the CompactFlash (http://searchstorage.techtarget.com/sDefinition/0,,sid5_gci836292,00.html) card. Both MMC and SD cards provide encryption (http://searchappsecurity.techtarget.com/sDefinition/0,,sid92_gci212062,00.html) capabilities for protected content to ensure secure distribution of copyrighted material, such as digital music, video, and eBooks, but SD cards are available with storage capacities as high as 128MB, with a 512MB SD card expected to be available by late 2002.

SD cards are more rugged than traditional storage media. They have an operating shock rating (basically, the height you can drop them from and still have them work) of 2,000 Gs, compared to a 100-200 G rating for the mechanical drive of the typical portable computing device. This translates to a drop to the floor from 10 feet, as compared to a single foot for the mechanical disk drive. Both MMC and SD cards use metal connector contacts, instead of the traditional pins-and-plugs, so they aren't as prone to damage during handling.

The SD card was jointly developed by Matsu****a, SanDisk, and Toshiba.

TH Note: The last line is the vBulletin censor chip at work. :mad:

[Freehold Fred]

Thanks, Terry,

But when they designate SD/MMC literally, does that mean they are the same or that the camera can take either?

Fred

[mylanta]

Fred I don't think so I think apart from how they work they are all different sizes and I thiink the MMC is considerably smaller...I think you need to consult the camera maker for that.

[compusimple]

I have a 1 gb sd card. purchased in 2005.

Elliott

[Terry Hanushek]

Fred

But when they designate SD/MMC literally, does that mean they are the same or that the camera can take either?
I think that Rich is right about checking the camera specifications. I looked at several cameras currently available from Staples. Most had a memory type of Secure Digital. One used Compact Flash and another (a Canon) had a memory type of Secure Digital / MMC. A couple (Olympus and Sony) appeared to have their own memory systems. Gee, imagine Sony with proprietary media.

I also got the following quote from a memory supplier (Memory Ten) site:

At about the size of a postage stamp, the MultiMedia Memory Flash Card is an ultra-small, high storage solution for MP3 music players, digital video, cellular phones, and global positioning systems (GPS). A 64MB MultiMedia Memory Card holds 64 minutes of MP3 or about 40,000 book pages.

A number of consumer portable device companies manufacture their products with slot(s) supporting both MMC and SD formats. Beside price, the biggest advantage of the MultiMediaCard standard —it was developed for all the leading open systems platforms. This technology is an open standard available to any company who wants to improve upon it or develop products for it. This includes Linux and all other Unix variants. Linux companies will easily be able to develop products for MMC cards. The SD standard was developed essentially for the Microsoft Windows platform. Sometimes, to get at the real difference between two competing standards, one must also view the forces driving their adoption.

HTH

Terry

[Freehold Fred]

Thanks to all who responded.

I have concluded that some cameras CAN use SD or MMC when designated SD/MMC, though SD is preferable. From SanDisk:

"New SD Card slots will accept existing MultiMediaCards, allowing an easy migration path for future SD Cards"

Also, need to consider transfer rate and max size compatibility.

From Inet sources:
================================================== ==============

SD and MMC (MultiMediaCard) cards are nearly identical on the outside but
technically different on the inside. Not all cameras that use SD can also
use MMC cards, check your camera's user manual. SD cards are generally
faster than MMC cards. Lately we have seen many new 2GB and 4GB size cards hit the market - most cameras, even the new ones, won't work with cards larger than 2GB unless specified by the manufacturer.

SD cards range in size from 16MB up to 4GB. As with other flash media,
SD cards come in different transfer speed ratings. Most SD cards not marked
"High Speed" or "Ultra High Speed" are probably only ~2Mb/s capable. The
latest cards are capable of transferring data at up to 20Mb/s such as the
ATP 150x or Pretec 133x cards. Transfer speed is an important factor if
you record high framerate motion video or high quality audio tracks. Many
digital camera makers only certify their 30fps VGA motion video capability
when using "high speed" SD cards.


Fred

[snip]
One used Compact Flash and another (a Canon) had a memory type of Secure Digital / MMC.

[snip]

[I]A number of consumer portable device companies manufacture their products with slot(s) supporting both MMC and SD formats.

HTH

Terry

[Freehold Fred]

Another confusing issue: transfer rates (faster is better, but is there a point of diminishing returns?).

60X = 10 Mbps and is called "hi-speed"

Some "hi-speeds are only 10X."

Kodak rates their SD chips as optimized for '30fps' referring to video, but also calls them hi-speed.

Then there is ultra hi-speed.

What is the standard here for EXTRA LARGE EGGS :lol:? Are these rates RW during a photo shoot also applicable to transfer rates in uploading to PC. JTOL (Just Thinking Out Loud).

Any clarity of explanation from anyone would be appreciated.

Fred