Memory Cards: How fast is overkill?

[DB83]

I'm looking to buy the canon 7d when it comes out which uses CF. These new memory cards just released by SanDisk can transfer up to 90MB/sec. That's great and all, but they cost hundreds for even the small capacity ones. So the question is: how much transfer rate in memory cards do I really need? I think the camera has its own buffer in which it stores continuous shot data while it transfers onto the card, so.. the faster the card the faster it gets cleared or is there a limitation in the camera itself? I'm looking to get the best performance that I can, even though I may not need it all the time.

 

[musicaleCA]

The faster the card, the faster the buffer gets cleared, the faster you can shoot. Definitely helpful in extremely fast moving situations, but more helpful in fast moving situations where the flexibility of RAW in post-processing is also extremely important.

In other words, get the fastest, most reliable memory you can afford. UDMA CF cards are the way to go.

 

[DB83]

First of all, I'd like to ask: If I get a memory card that can support transfer from camera to card faster than the camera can shoot and store in its buffer, can the camera shoot indefinitely until the card is full?
Now to show you guys some comparisons that I made of the results from Rob Galbraith DPI: Canon EOS 5D Mark II.



All these are involving the SanDisk Extreme IV 45MB/s Edition 16GB
Camera Burst Speed(fps) JPEG write speed (MB/s) RAW write speed (MB/s)
Canon 50D 6.3 23.6 31.6
Nikon D300 6 23.4 27.1
Nikon D700 5 20.3 27.6
Canon 5d Mark II 3.9 25.5 30.9
Nikon D3 9 21.1 27.7



With the cards able to be written on at a speed of 45MB/s and the cameras only using up to 31.6MB/s is it fair to say that with these cameras, it is the camera that limits the data transfer? Is it safe to say that even with the new 90MB/s cards from Sandisk, these cards would not show that much improvement if at all? Then is it fair to say that these cards are sufficient to make these cameras perform at the peak of their ability?
Obviously the camera that I will be getting (the Canon 7D) is not amongst the cameras tested, but it shoots at 8fps which is within a range covered by the above cameras.

 

[musicaleCA]

Mmm, no, not so much. The camera is the limiting factor to a marginal extent (e.g. the slow-down above between RAW and JPG is because of the conversion that takes place from RAW to JPG to output a JPG image). Non-volatile (meaning it doesn't lose its stored data when power is cut-off) memory is usually the slowest part of any system. Those write speeds are all in the same range, which allows for what I would call the strangeness factor (that is, I've given up trying to figure out why the darn speeds vary slightly between different pieces of equipment, but this is normal). You should note that RAW files are big puppies, and with the 18MP that the 7D spews out, they're going to be very big puppies. Easily, well, 18MB a piece.

A faster card will always be better for you. As for the card being faster than the buffer? Not going to happen. Ever, I suspect. That buffer is right on the circuit board, whereas the data to the card needs to go through a bunch of other annoyances (including dealing with a file system). And the buffer is using volatile memory, not non-volatile memory, and I've never seen non-volatile memory that is faster than the current volatile memory available. RAM will likely always be faster, if simply because RAM doesn't use a file system to store data.

 

[Village Idiot]

A faster card will always be better for you.

So you're saying using a UDMA card in a non UDMA camera will be more beneficial than using something like and EX III over an EX IV?

 

[Dao]

Another point is, the faster the CF card, the shorter time to transfer the BIG RAW files to the computer (via card reader). But is it worth it? Maybe yes for you. But no for me right now.

 

[DB83]

I'm not worried about the transfer time from card to computer at this point. I'm going to be using the camera for leisure, not professionally.

 

[musicaleCA]

A faster card will always be better for you.

So you're saying using a UDMA card in a non UDMA camera will be more beneficial than using something like and EX III over an EX IV?

Within reasonable limits. Obviously if the camera doesn't support UDMA you're not going to see much benefit. I'm speaking about using all current technology here. If you buy the latest and greatest camera, it's worth it to put in the latest and greatest memory too, and that's the case above.

 

[Garbz]

The fastest cards outperform pretty much most camera interfaces. There's a limit to how fast you can clear your buffer and the fastest memory card is not required for that.

Also I don't have the fastest card, but my computer Lightroom's import the speed limit of the transfer is governed by how fast my Core2Quad can generate previews for my images. This is also slower than the transfer speed of my card.

 

[FrankLamont]

I'd say that is overkill, that particular card... for most cameras.

The 8fps offered by the 7D is another factor. Or is it the movie you're worried about?

Weigh size vs. speed up, if price is a concern.

Otherwise, Extreme IV or V's have served pro's fine for these last few years.

 

[reng2009]

Another point is, the faster the CF card, the shorter time to transfer the BIG RAW files to the computer (via card reader). But is it worth it? Maybe yes for you. But no for me right now.

That's exactly what my plan is. I bought two UDMA cards for my 40D, even though it doesn't support UDMA. I'm going to buy a SanDisk ImageMate All-in-One card reader to let me upload files to my laptop as quickly as possible.

 

[Village Idiot]

A faster card will always be better for you.

So you're saying using a UDMA card in a non UDMA camera will be more beneficial than using something like and EX III over an EX IV?

Within reasonable limits. Obviously if the camera doesn't support UDMA you're not going to see much benefit. I'm speaking about using all current technology here. If you buy the latest and greatest camera, it's worth it to put in the latest and greatest memory too, and that's the case above.

So the OP should spend $800 on a 64GB SanDisk card that transfers at 90MB/s? I mean, it's probably more than their camera, but it's the latest and greatest. :er:

 

[reng2009]

Another point is, the faster the CF card, the shorter time to transfer the BIG RAW files to the computer (via card reader). But is it worth it? Maybe yes for you. But no for me right now.

That's exactly what my plan is. I bought two UDMA cards for my 40D, even though it doesn't support UDMA. I'm going to buy a SanDisk ImageMate All-in-One card reader to let me upload files to my laptop as quickly as possible.

I bought the SanDisk card reader. Very nice! Cool design, as in Apple-cool.

I can upload large RAW files at about 30MB/s. Not bad at all.

Highly recommended.