SanDisk "Extreme Pro" 16 GB CF and Canon 7D?

TangoJuliet

I was on B&H earlier looking for another CF card for my Canon 7D. I saw the SanDisk "Extreme Pro" 16GB with a 90/mbs write speed. I have an 8 GB 30/mbs and two 4 GB cards, all SanDisk, and I've never had any issues. Do you think I'd have any issues with this new card in my 7D? My experience tells me no, but I've seen many posts where people seem to have problems with some 'faster' cards in the 7D. :dunno

ziggy53

Flash card compatibility boils down to 2 basic issues:

1. Compatibly of the card with the intended camera.
2. Compatibly of the card with the intended transfer method into a computer.

I agree that you need compatibility with the intended camera, but ignoring compatibility of the card with the intended transfer method into a computer can be just as troublesome and leads people into thinking that the camera may have caused the problem, when it was the transfer method causing the problem.

Getting back to your question I do not see people having problems with the Canon 7D and the SanDisk "Extreme Pro" 16GB, 90MB/s speed rating, compact flash card. It is my opinion that the the 7D probably cannot realize much advantage over the SanDisk "Extreme" 16GB, 60MB/s speed rating, compact flash card. I suggest that the SanDisk "Extreme" cards are probably a better value for your camera, unless you purchase an extremely fast CF card reader that can allow the extremely fast transfer speeds that the faster card allows and you wish the fastest possible transfer into a computer.

Rob Galbraith tested the Extreme Pro cards with a number of cameras back in 2009 and the Extreme Pro cards were compatible with Canon cameras even back to older cameras like the original Canon 5D and the 10D. Most of the compatibility with camera problems relate to Nikon cameras.

You can read the review here:

http://www.robgalbraith.com/bins/content_page.asp?cid=7-10043-10255

TangoJuliet

Thanks for replying. My current 8 GB card has a write speed of only 30/mbs. When I was out shooting fireworks on Monday night, it seemed to take forever to buffer. My thought was that the 90/mbs would speed that up. Am I wrong?

I normally transfer images to the computer using an external card reader, and yes, it's a bit slow also, but I can live with it because I usually do other things while the images transfer.

ziggy53

TangoJuliet wrote: »

Thanks for replying. My current 8 GB card has a write speed of only 30/mbs. When I was out shooting fireworks on Monday night, it seemed to take forever to buffer. My thought was that the 90/mbs would speed that up. Am I wrong?

...

The Canon 5D MKII is probably very similar in real write and read speed rates compared to the 7D.

According to the Rob G. site the SanDisk Extreme III 30MB/s Edition 8GB has "measured" write speeds of 20-23 MB/s on the 5D MKII (JPG and RAW respectively). The SanDisk Extreme 16GB measured write speeds of 35.6 MB/s for RAW, and the SanDisk Extreme Pro 16GB measured write speeds of 40.8 MB/s for RAW files (only 5 MB/s more), but the "Pro" cards cost a lot more.

Assuming that the 7D measured similarly the SanDisk Extreme 16GB will give you most of the potential speed benefit at a better price.

TangoJuliet

ziggy53 wrote: »

The SanDisk Extreme 16GB measured write speeds of 35.6 MB/s for RAW, and the SanDisk Extreme Pro 16GB measured write speeds of 40.8 MB/s for RAW files (only 5 MB/s more), but the "Pro" cards cost a lot more.

Assuming that the 7D measured similarly the SanDisk Extreme 16GB will give you most of the potential speed benefit at a better price.

Good point. I'll be renting a 5DmkII later this month along with a wide angle lens. I'll probably put my 8 GB card in it, and buy a new 16 GB Extreme for the 7D.

NeilL

I had an idea that camera bodies/models had a characteristic buffer speed(?).

How does that fit with all the card speed options?

Neil

ziggy53

NeilL wrote: »

I had an idea that camera bodies/models had a characteristic buffer speed(?).

How does that fit with all the card speed options?

Neil

Correct! The image buffer fills first and then transfers the image files to the memory card for storage. "Smart" image buffers, which most modern dSLRs have, will allow shooting until the buffer fills completely and then the shooting rate slows considerably, depending upon your shooting mode. (Small JPGs tend to clear the buffer fastest and RAW + largest JPGs tend to clear the buffer the slowest.) With smart buffers you can continue shooting even at a reduced speed, where older normal buffers would force you to suspend shooting until all image files cleared from the buffer.

Some cameras will even allow continuous shooting of JPGs at full speed until the card itself is full, assuming a fast enough card. (The Canon 5D MKII has this capability, for instance, using very fast UDMA cards.)

In short, buffer speed and buffer capacity tend to be the biggest factor in overall continuous shooting rate, followed by a fast card transfer write speed to clear the buffer.

For video-capable dSLRs, used in video mode, all you need is a card fast enough to carry the video throughput of the system. The buffer still has some potential impact, but the card write speed is more of the limiting factor.

Again, a faster card can be a tremendous aid in getting files to the computer assuming a faster card transfer mechanism as well.

TangoJuliet

I took into consideration what you said about the price versus the minimal gain in write speed, and have decided instead on another 8 GB card. In one day at a model aviation contest, I could fill an entire 8 GB card, but probably just, even at a full scale airshow. So I've decided instaed that two 8 GB cards and my other 4 and 2 GB cards can cover my needs. I think several smaller cards might be better than one bigger card anyway, for insurance purposes.

ThatCanonGuy

TangoJuliet wrote: »

I took into consideration what you said about the price versus the minimal gain in write speed, and have decided instead on another 8 GB card. In one day at a model aviation contest, I could fill an entire 8 GB card, but probably just, even at a full scale airshow. So I've decided instaed that two 8 GB cards and my other 4 and 2 GB cards can cover my needs. I think several smaller cards might be better than one bigger card anyway, for insurance purposes.

Yes. It's better to have 2 8GB's than 1 16GB IMHO. I personally don't like going over 8GB with my cards. I have three 8GB's and a 4GB, and more backups if needed. I'll probably hold off on the 16GB's until I upgrade to that 1D Mark VII... or maybe 32GB would be better for that?

Overfocused

For reference I get 45MB/sec write with Lexar 600x (90MB) cards in the MKII

ThatCanonGuy

Why? That doesn't make sense. That's why the cost so much... their speed! Have you ever tried a Sandisk, Kingston or Hoodman as a comparison? I thought the 5DII was UDMA... maybe the buffer is the bottleneck? Hmm...

ziggy53

Overfocused wrote: »

For reference I get 45MB/sec write with Lexar 600x (90MB) cards in the MKII

How does your testing methodology compare to that at the Rob G. site? (... write 20 Large Fine JPEG and then 10 RAW .CR2 photos to the memory card. Timing commenced when the camera's card status light illuminated, and stopped when the light went out. Each test cycle was performed 3 times ...)

Overfocused

ziggy53 wrote: »

How does your testing methodology compare to that at the Rob G. site? (... write 20 Large Fine JPEG and then 10 RAW .CR2 photos to the memory card. Timing commenced when the camera's card status light illuminated, and stopped when the light went out. Each test cycle was performed 3 times ...)

That's where I originally got the reference for the 600x card (And used that method)

It can write 2 RAWs/second indefinitely after the buffer fills

[Deleted User]

Rob Galbraith also tested the Lexar 600x CF card on the 7D and other cameras in October of 2009. It tested faster than the other cards. I bought two 16GB cards and have been happy with them. Also like the 32GB 400x Transcend card after two months of use.

http://www.robgalbraith.com/bins/content_page.asp?cid=7-10044-10297