If I'm happy with the speed, do I really need a faster class 10 or 30MB/s card for my DSLR?

Question

My camera came with 4GB class 10, 30 MB/sec card. I wanted to upgrade to high capacity memory card but I was skeptical, a lower speed card such as class 10, 20MB/sec will cripple my camera when I use it at its highest setting. I checked reviews online for super fast cards. I found this review quite useful. When I did the same test on my camera, I would notice it would stop in the middle (quite long pauses) and I really did not get the full 4 f/s picture that my camera is capable of.

Recently I went to NYC and used up all the memory of my 4GB card in one day so I got worried, I need a high capacity card esp because I want to shoot in raw. Instead of buying an new fast card first, I tried my 16 GB, class 2, micro SD card from my phone and put it test :)

It could shoot continuously (with no delay) at 2 or 2.2 f/s.This was in RAW format. I was actually very happy with that! I thought it would just totally cripple my camera. I did video test too on High Quality, 25 fps and it came out good, no jerks. So I am really happy that I can use my 16 GB class 2 card in my camera.

My question is, am I missing something? Do we really need a 30MB/sec card for the DSLR? Will the photo and video quality be the same with both the cards?

One thing I noticed with class 2 card is that browsing in camera was slow (noticeably slow), but as long as the camera captures the moments right, I am happy with it. Am I missing anything?

This question is more intended to ward, is it kind of myth that you have to use 30MB/sec card?

Answer

This other question covers how to figure out what speed you really need. But to answer the other part of what you are asking: No, card speed does not affect image quality in any way. The image files are digital, and it's not like analog cassette tapes where the composition of the media can make a difference. The only case image quality could be affected is when the slower speed forces you to choose a lower-quality setting in order to make smaller files. But that's a choice you'd make intentionally.

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