The Sports Photo Guy

Never believe the label when it comes to manufacturer speed claims – they are almost always based on unrealistic test conditions.  A reader wonders why his 533x card can’t achieve anywhere near 400x speeds.  See why below.

I received the following comment on the site today:

I have a Canon 5D MK2 and was told that I need 40mb/s write speed (about 300X) to get smooth HD video with the camera. My agent has a 300X card and it works great. Anything less than that produces a “choppy” movie. Per various recommendations, I bought the new 32gb CF Photoflash card (533x). I just shot video with it in my 5D MK2 and the movies are extremely choppy. The movie is worse than using a Kingston 133x card! Either this card does not write at the speed advertised or something else is going on? Any ideas? Thanks.  - Bob Jensen

Well, Bob, let’s see…533x equals almost 80 MB/sec, which PhotoFast claims as read/write speed for the 533x Plus card and read speed only for the standard 533x card.  So if you got “only” the standard 533x card, you have a claimed write speed of 40 MB/sec.  But according to your experience, you’re not getting that minimum 40 MB/sec write speed.

I don’t shoot or test Canon, but from what I’ve read, the 5D Mk II can record files faster than any camera that Nikon currently produces.  According to Rob Galbraith, the 533x Plus reaches 45 MB/sec in that camera, while the standard 533x only manages 30 MB/sec.  That may indeed explain the choppiness you are seeing.  (Note that 30 MB/sec is only about 200x – a far cry from the 533x on the label!)

If you got the standard 533x, you might see if PhotoFast will let you exchange it for a 533x Plus card.  Otherwise, I’d seek a refund and look for one of  SanDisk’s new 90 MB/sec Extreme Pro cards.