Summary: CF memory cards are faster than SD cards for capturing raw images on the Canon D5 mark IV camera. Don’t use speed alone as an indicator of whether an SD card would outperform a CF card. A 50 MB/s CF card out performs a 90 MB/s SD card in my tests.
I’m a photographer that enjoys shooting wildlife and baseball pitchers, so burst mode is very important to me. I asked other photographers which of the two supported memory cards was better at bursting, and they used the memory speed printed on the card. I heard other photographers say that they thought the CF card was faster. I decided to test it.
Setup: I used my D5 set to shutter priority of 1/250 in high speed burst mode shooting continuous with a 24-70 mm canon lense sitting stationary on my desk. The camera was set to shooting RAW, the largest and most difficult image.
The tests: I recorded the number of shots taken in 10 seconds, then I recorded the number of shots taken in 20 seconds. At 20 seconds, I recorded how long it too to stop writing to camera memory (seconds to clear the buffer), this ranged from 5.9 seconds to 44.2 seconds. I also recorded the number of shot in burst mode, plus 1 shot (so your camera bursts then slows for that last shot). Finally I computed when the shooting rate from 10 seconds to 20 seconds in shots per second.
|Type||Manufacturer||Speed||10 Second||20 Second||Burst + 1||Full Buffer Rate||seconds to clear buffer|
|(shots per second)||(after 20 seconds)|
|CF||Sandisk Extreme||160 MB/s||38||64||19||2.6||5.9|
|CF||Sandisk Ultra||50 MB/s||24||36||15||1.1||13.0|
|SD||Sandisk Extreme Pro||95 MB/s||30||48||17||1.8||8.1|
|SD||Sandisk Extreme Pro||90 MB/s||23||33||16||1.0||15.3|
|SD||Sandisk Ultra||80 MB/s||17||20||15||0.3||36.5|
|SD||Sandisk Ultra||30 MB/s||16||19||15||0.3||44.2|
The key result was that the slower CF card out performed the faster SD card, so transfer speed is a factor but not the only one.