My first digital camera came with an 8MB card, good for 20 pictures -- not even equivalent to a roll of chemical-based film. I shopped locally for a 64MB card, and was amused by the recation. At the London Drugs photo counter, the saleman mused, "64MB? I've heard of them." At the time (Summer 1999), 20MB was the largest they carried. At Future Shop, the saleman insulted me: "Why would you ever want that much memory?"
(Future Shop insulted me again recently, when I wanted to buy the Canon S1iS. They were out of stock: "If you care to leave a deposit, I can get in some more tomorrow or the day after." Leave a deposit? I got the camera at London Drugs, where it was $30 cheaper.)
I resorted to buying the 64MB card mail order from the United States. By the time it arrived at my door in Canada, it cost me CDN$330. Later, I also got a 96MB card.
How much memory is enough?
Most digital cameras are limited to a maximum of 2GB, because they use FAT16 ("file allocation system," which determines how data is stored on the card. Read more here.) Newer cameras use FAT32, which, in theory, can handle 2TB (2 terrabytes = 4,000 gigabytes). In practice, however, other other limitations of the camera's programming code limit the maximum memory that can be accessed.
I find that the 64MB and 96MB cards are adequate for everyday shooting. My daughter just got a Pentax camera, I got her a 256MB SD (secure digital) card for US$60. That'll hold about 600 photos, ideal for her France trip next Spring.
When I don't want to worry about limits, I take along my 1GB Microdrive. It's limited to use in cameras that accept CompactFlash Type II slots -- usually found only in "prosumer" cameras, like Canons.
Rules of Thumb
I use these rules of thumb to determine capacity and need.
* Typical pictures are 400KB in filesize. That's for 3-megapixel images at normal JPEG compression. To find the capacity of a card, divide its MB memory by 0.4. For example, the 96MB card holds 240 photos (96 / 0.4 = 240).
* On trips, I typically take 100 pictures a day. For a two-week vacation, that's 1,400 photos -- roughly.
* Combine the two rules-of-thumb to find the size of memory card you need to take on vacation. For my 2-week vacation (1,400 photos), I would need at least a 512MB card -- 1,400 photos x 0.4MB per photo = 560MB. Your milage will vary.
Does this work in practice? During last summer's 2-week trip to New Zealand, I took 1,600 photos, which fit comfortably on the 1GB Microdrive.
The number of digital photographs that fit a given size of memory card is a frustrating calculation that varies according to: (1) the resolution; (2) the level of compression; and (3) the subject matter. While I use 400KB based on the average of all my photos, the actual values vary from under 50KB (a night time photo that consists mostly of black) to 2.8MB for a highly textured photo of berry-bearing tree and grass.
Moster Capacity Cards
SanDisk said it would start selling its 4GB CompactFlash memory card for US$999 in April. But the Web site shows 2GB ($440) as the largest size.
How much is 4GB? SanDisk says the card could hold eight hours of MPEG4 video. (MPEG4 is heavily compressed.) Most cameras use AVI or MOV format, however, which are not as heavily compressed; this card would hold about about 30 minutes of video. Here is another comparison. Since August, 1999 I've taken just over 20,000 dgital photographs, which consume about 10GB on my computer's external hard drive.
Lexar has an 8GB flash memory card for $5,500. This card requires the slightly-wider CompactFlash II slot, and works only with devices that support FAT32.
Pretec predicts it will ship by year's end a 12GB CompactFlash memory card for US$9,999 (works out to $833 per gigabyte). Their cheapest 3GB card is $1,599, and the 6GB card costs $4,318. They currently offer a free MP3 player with the purchase of the 1GB card ($299).
IBM's 4GB version of its MicroDrive (with PC Card adapter) is $499. I have the 1GB model for my camera. Miniature hard drives are cheaper than flash memory, but require that your camera be able to handle the Type II slot for CompactFlash cards.
We tend to forget that flash memory is really quite slow. Lexar, for example, considers 6MB/sec "high speed," designating it 40x. Compare that with the 400-480MB/sec speed of FireWire and USB 2.
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At the other end of the scale, SanDisk has 32MB ($15) and 64MB ($25) memory cards that the company hopes are cheap enough to become digital negatives. People don't like the hassle of transfering pictures from camera to computer, and so SanDisk's idea is that you leave your photos on the cards, and repeatedly buy more of their memory.
If the 32MB card were priced like the 4GB card, it would be under $8. If the 4GB card were priced like a desktop hard drive, it would be four dollars.
My first computer, a Victor 9000 PC, came with 128KB RAM. To upgrade to the full 896MB (the Victor wasn't limited to 640KB, like the IBM PC) would have cost me $10,000 in 1984.
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