I have tried to stay on top of Secure Digital memory cards issues as best as possible. Additionally, I have conducted extensive manufacturer product compatibility beta testing.
First, this past week, while looking over the M8, I spoke with three Leica representatives who all adamantly assured me that the Leica M8 does indeed support SDHC cards in addition to traditional Secure Digital memory cards. However, there has been a ongoing record of inaccuracies in published Leica documents regarding digital specs, which have fueled confusion, and the latest Leica issued sheet on “Compatible SD Memory Cards for the Leica M8” speaks nothing to SDHC memory cards.
Second, there is a bit of confusing in the market place over SD and SDHC memory cards and host devices due mainly in part to the fact that many card manufacturers, popular bands included, have failed to follow the
SD Card Association standards.
Basically Secure Digital and SDHC products fall with in four categories:
• SD Specification Version 1.0
• SD Specification Version 1.1
• SD Specification Version 2.0
• Non-compliant SD memory cards
SD Specification Version 1.0 provides for data transfer of 4bits at 25MHz.
SD Specification Version 1.1 allows for data transfer of 8bits at 50MHz. SD Spec v.1.1 Secure Digital memory cards are usually denoted by speed ratings greater than 100X. One memory card manufacturer, of extreme popularity, as had a card out on the market that is neither spec v. 1.0 or v. 1.1. It runs at the faster 50MHz but with only 4bits of data transfer, not 8bits.
SD Specification Version 2.0, aka SDHC, officially supports FAT32, which enables recognition of capacities beyond 2GB. Actually, to be more exact, FAT16 covers up to 2.2GB. Of significant note is the fact that SDHC cards use sector addressing as opposed to the traditional byte addressing of previous SD cards. All SDHC memory cards are denoted by the SDHC emblem.
Properly designed SD Specification Version 2.0 host devices accept all previous SD spec version memory cards. Therefore, the latest SDHC compliant cameras and readers will host all previous version cards that adhered strictly to one of the SD Card Association standards.
There are a number of 4GB Secure Digital memory cards that have been introduced in the past year. Theses are not SDHC memory cards and were designed and released to market before the SD Specification Version 2.0 was completed. They do not adhere to any industry standard. They do not provide sector addressing. They may or may not work in various host devices and this has lead, in a large part, to the current round of confusion. My advance for long term reliability and usability with future devices would be to steer clear of this product.
SDHC memory cards are not speed rated by an “X factor” but rather denoted as fitting into a “Class.” The Class rating was implemented as a more faithful indication of what type of performance a given card could safely be expected to delivery. Previous X factor ratings were fairly misleading at times to what could actually be achieved.
Personally, I am awaiting the release of the new 8GB SDHC memory cards from ATP, a company known for it’s steadfast adherence to SD Card Association standards, selection of top quality components and industrial strength manufacturing and durability.
Properly designed memory cards that are properly used and maintain are of little cause of concern for failure. This includes always reformatting the card, in said camera, after each session and utilizing a card reader, in place of the camera, to transfer images to the computer.
