Speed, CF Card and your Needs
The speed of your CF card may be just as important as the storage. The first question in terms of speed is; how important is speed to your photography mission? If you are the type of photographer that does a lot of sport photography or children while playing and likes to use the burst feature on your DSLR, then the transfer rate is very important to you. The transfer rate is the speed at which the CF card is able to write from the camera. Remember though that the camera has a speed at which it is able to transfer data to the card as well. Both need to be considered. If your camera only has the ability to transfer data at 6 MB/s, then paying for a compact flash card that has the ability to transfer data at 30 MB/s doesn’t make much sense. Understanding how the transfer rate works with a certain piece of equipment can help you save some money by not buying a card that was built for a much faster camera.
For instance; the Nikon D3200 claims a burst speed of 4 frames per second. Also the D3200 has a buffer of 18 RAW images. The buffer can be thought of as a temporary holding place for the image in the camera’s memory before it is transferred to the CompactFlash card. The camera can write to its own memory faster than to the card, so this allows you to take the next shot quickly rather than waiting for the transfer to complete. Beings that the camera’s image processor itself limits the camera to 4fps (frames per second), a faster memory card will not increase this performance at all. And since the buffer can hold 100 frames, you most likely need not worry about exceeding it. However, this is only for jpeg files. If you have a Nikon D3000 and want to shoot NEF (RAW) files, the buffer only allows 6 frames to be held before you are dependent on the speed of the card. Once the buffer is full, your speed is dependent on how fast the camera and CF card work together to get the files onto the card. So if you burst those first 6 frames, you will get 3 frames per second for 2 seconds but then the burst rate will fall dramatically depending on the performance of the camera and card.
So if you own a D3000 and you are going to shoot RAW files and you think you will need to burst more than 6 shots in a row, then you will want to invest in the fastest and best compact flash card for your camera. Whereas if you know that you are going to shoot jpeg always or you know that you really don’t need burst speeds that carry over 6 shots, you can save some money and get away with a slower card and not notice a difference.If you are using an older camera, you know who you are! Often a faster card may be an impairment and not an asset in your needs, older models aren't capable of utilizing advanced cf cards higher speeds effectively if not at all. Always consult the seller before buying if this is you.