Lowest Read/Write Speed for 1080P

I saw a 64MB class 10 UHS1 Sony SD card on sale from a reputable retailer that seemed like a great deal. The read write speed is 40MB/sec

Is this enough to handle the buffer on a 70D shooting in 1080P?

The card I currently use has a faster read/write speed.

I remember reading somewhere where a class 6 card is about the bare minimum for 1080p and even there it is somewhat card dependent. Class 10 cards are meant for 1080p.

The 40mbs is typically the read speed on a fast 3.0 reader. Write speeds are typically less.

I would look for that card online and read the reviews. Many times people will do speed tests that can be helpful for deciding if you want to purchase one.

I have a sandisk extreme 80mbs card that writes to my t3i at 20mbs. Plenty fast for video. Would think the buffer is larger and faster on the 70d. And I think the 70d takes advantage of uhs-1 where my t3i does not.

Unless the card you are looking at has poor write speeds you should probably be fine. Am sure others on here are far more knowledgeable than I am on this topic. Hopefully they will chime in.

gjl711 wrote in post #16387966
I remember reading somewhere where a class 6 card is about the bare minimum for 1080p and even there it is somewhat card dependent. Class 10 cards are meant for 1080p.

Awesome... When I first got the camera, I had a class 6 card laying around and it couldn't handle buffer. Luckily I had a back up. I never want that to happen again.

Sometimes having a 64 gb card isn't a good thing. That's a lot of data to lose if it gets corrupt. Just a thought.

Have a look at Sandisk Extreme series, Class 10 with 45mb/s read and write. I have been using two 16GB ones with my 60D and there is no issue with 1080p or even burst mode. Even 30mb/s 8GB extremes I have, work well.

My 32GB Transcend Class 10, 17MB/s write speed card is not fast enough.
My 64GB Wintec UHS-I, 50MB/s write speed card is fast enough.

nyc2sd wrote in post #16387941
I saw a 64MB class 10 UHS1 Sony SD card on sale from a reputable retailer that seemed like a great deal. The read write speed is 40MB/sec.

There is a manual that comes with the 70D. You don't have to read very far (Page 3) to find the info you require -

It depends on the compression method used (explained on p. 265) IPB requires a write speed of 6 MB/s; ALL-I needs 20 MB/s.