I've been looking at the 32gb Sandisk Extreme 3's, but I'm wondering if the more expensive 16gb Extreme 4's would be better for the 7d. I know the 4's are more pro but maybe not so much better to justify the price.
I haven't noticed any issues. But then again, I'm ashamed to say that I haven't subjected my gear to a lot of use, either.
Kingston's a good brand, and the transfer rates of today's memory cards don't even saturate USB 2.0. 44 Mbps (5.5 MB/s) recording bandwidth is not very demanding at all. I don't see the point of using expensive SanDisk cards with the 5D or 7D.
Thanks a lot for the quick responses guys. I think I'll order one too - can't beat it for the price. Plus, I'm also a big Kingston fan - all my USB sticks are Kingston, I just haven't used any of their CF cards.
Ordering this so I should have it when the 7D arrives. 4GB = 12 minutes at 720 or 1080p, right? So that should give me 96 minutes worth of footage. That will work out nicely I believe. Keep the couple 2 and 4GBs I already have for photos and stuff.
I think I'm going to go for the 16gb Sandisk Extreme IV's. Maybe I'm just superstitious but with heavy continous and repeated HD video recording, I don't want to take any chances. With the rebate, if you buy three IV 16gbs seperately on Amazon, they only cost US$118.00 each.
I doubt that a SanDisk card is much less likely to fail than a Kingston. If a card fails, it fails, no matter what the brand. The end result is the same. A lower quality card might fail sooner. But with ANY card, you'll still lose everything that you have on it, without warning, and it could be in the middle of a shoot.
"Premium" brands like SanDisk use FUD in their marketing. To what extent does the price premium translate into real-world gains? How do you justify spending at least double the price? I don't think that a competently manufactured card would last only half as long as a "premium" card.
I haven't worn-out a card. But I'm just trying to address the concerns of those who choose the expensive cards because of worries about "reliability" and "lifespan." Poorly manufactured cards might spontaneously die after weeks or months, but a competently manufactured card should last a long time indeed.
But a card with half of the capacity of another card would go through double the number of write/rewrite cycles given the same amount of data, so the card would last about half as long. It's not like there's a huge difference in durability between different makes of flash memory.
I'm still debating. The Sandisks seem to have the best reputations, and I've always been happy with them. But for all I know, the other brands may be just as good.
Keep an eye on the bits (b) and bytes (B). Someone please check my math/reasoning.
Lets just overestimate and say the 7D puts out a consistent 50 Mbps (that's megabits).
That translates into 6.25 MBps (that's megabytes) because there are 8 bits in a byte (50Mbps/8=6.25 MBps).
So, theoretically, a card that has a 6.25 MBps read speed would be sufficient. However, listed read speeds often aren't spot on as inefficiencies exist within the card.
The 133x card should do 25 MBps - which is four times the necessary theoretical read speed of 6.25 MBps. That should provide more than enough room for inefficiency.
If you want to get some to try out, order Extreme III 4GB cards from Amazon. They offer them cheaper than anyone, they're about $30, and they're sold through Adorama, which makes them eligible for the rebate. Get two cards, pay $60, get $30 back from SanDisk, and you've got 8GB of storage for $30 total.