Memory cards-a cautionary tale
Tuesday, October 28th, 2008I guess most of us buy our memory cards on price. Well, why not? I mean they are all much of a muchness (that looks terrible in print).
Wrong.
I am asked from time to time which brand of cards they should be using. I know I have tended to stick to the big names (Sandisk and Lexar) and buy them from someone I can have a discussion with when/if they go wrong/fail. So far it has worked. But there is more to it than that.
Firstly, you need to consider write-speed, the time it takes your camera to write the file to the card. This will vary according to the make and model of camera. If you have a camera that takes 2 different forms of card (i.e Compact Flash and SD), then you find that performance varies.
Brand is another issue. One manufacturer’s 200x card may well differ from another’s. And don’t believe that a card with an advertised write speed of 30Mb/sec (e.g Sandisk Extreme III) will actually deliver that. The culprit here is not the card, it is the camera. As an example is my Canon 1DS MKIII. A SanDisk Extreme III 30MB/s Edition 8GB ($NZ180.00) has an actual write speed for RAW files of 17.966MB/sec, in other words a little more than 1/2 the potential performance. A Sandisk Extreme 8.0Gb CF Ducati($325.00) has a write speed of 19.808MB/sec. Nearly twice the price, but not 2x the performance. Bang for the $$$, The former card represents better performance value. A Transcend Class 6 8GB SDHC card for the same camera has a write speed of 9.795MB/sec.
So how do I know all this? Because there is a cool site which has tested a whole array of cards with different cameras and published the data. You can access it here.
Read-speed is the time it takes to get the data off the card, and here the issues are the speed of your card-reader and the bus speed in your computer. If this matters, then buy a really good card reader. I recommend the Lexar Professional UDMA Reader. Quick and effective.
Lastly, how do you know that card you ordered online is the Real Deal? My friend SSG ordered one while overseas, A 16Gb Transcend. When he went to download it, it turned out to be only 8Gb in capacity. He was able to return it to the dealer who had sold it to him. Would it be that easy if he had ordered it from www.fornexttonothing.com? I wonder.
I note the Big Two are using holographic logos in their packaging. How reliable they are I am not certain.
Caveat emptor.









