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Cards, Readers, and Batteries

The Digic III processor in the Rebel XS/1000D supports both Secure Digital (SD) and Secure Digital High Capacity (SDHC) memory card formats. Memory cards are priced based on their Data Transfer Speed (DTS). Cards with a Class 2 rating are guaranteed to sustain a DTS of 2 megabytes/second, whereas Class 4 and Class 6 cards sustain rates of 4 and 6 megabytes/ second, respectively. The DTS numbers for the Digic III are not available from Canon. Suffice it to say that it’s very fast. I made a simple and totally unscientific test to determine how inexpensive SD cards compare to their faster, more expensive brethren just to see what would happen. The inexpensive card was a free 2GB giveaway from a local office supply store, whereas the other was a 2-GB SanDisk Extreme III card that reads/writes at a minimum DTS of 20MB/second. I set my Rebel to Continuous Shooting and began firing. The free card was slow enough that the buffer filled after 40 frames and then required approximately 20 more seconds to write the remaining images to the card. The SanDisk card was not able to overpower the buffer, registering more than 100 continuous frames before I stopped shooting. The camera needed less than a second to write remaining buffer data. What does this mean to you? First, any card will work perfectly well for basic, snapshot applications. There’s no need to spend a lot of money (and you can certainly get great results

with a freebie). However, if you plan on shooting sports or any subjects that require continuous shooting, spending more for a better card is a good idea.