Monday, February 20, 2012

Best SD or CF Card for Video

Because technology changes by the second, this post will likely be outdated the moment I post it.  Hopefully, however, you will still be able to glean some useful information to help you select a good card for your shooting purposes. (p.s. I will NOT be covering cards with wi-fi capability in this post; neither will I cover micro and mini cards).

There are two different data storage cards currently being utilized by Canon (and most other manufacturer’s): the SD card, and the CF card.  Canon T2i &T3i, and 60d use the SD card.  The 7D and 5D use a CF card.

The CF card is larger, thus easier to handle.  Most people also agree that the card is “sturdier” (it’s thicker and made of stronger materials) and less likely to fail for physical reasons.  The technology used to store the data is also different between the two.

SD card
CF card

The SD card can be SDSC, SDHC or SDXC.  DO NOT try to utilize the SDSC card for your HD Video.  It is too slow and will absolutely fail you.  While SDHC and SDXC cards are faster, the terms don’t necessarily have to do with speed but instead the capacity.  SDHC has a maximum capacity of 32GB (the common sizes are 8GB, 16GB, and 32GB).  SDCX have a capacity of 2TB, but we aren’t really seeing anything much over 128GB on the market at this time.

SD card speed can be defined by several standards.  One is by “class” (2, 4, 6, 10) and is intended to correspond to the MB per second rates for minimum sustained writing (i.e. Class 6 achieves 6MB/s).  The “x rating” is a multiple of the CD-ROM speed rating standard (1.2Mbit/sec) and will be shown as 100x, 133x, 266x, etc.  There is a relatively new standard called UHS that actually supports a higher clock frequency and starts out around 50MB/s.  At the time of posting, only a few devices support this new SD standard, however.

It is important to note  that these standards are governed only “in house,” so many manufacturers will claim their cards adhere to a class 10 speed, for instance, while real-world tests clearly show that they only achieve speeds in the class 4 range.  You can spend hours and hours (I have) trying to make sense of various brands and class ratings, comparing cards, reading reviews on various websites where people have actually done speed tests, etc… this is exactly why I’ve created this post.  Note also that even among cards that appear to be exactly the same (same brand, same model, same class) there can be wild variance with read/write speeds.  The better the brand, the greater the standards, and the less likely this is to happen, but of course, the more expensive the card.

An example of the above is a class 4 SanDisk 16GB card blowing a class 10 Transcend 16GB card right out of the water with both read and write times.  Theoretically any class 10 card should be absolutely acceptable for shooting HD Video, but many users report many cards failing in this regard.  While sometimes cards rated at class 4 report stellar performance shooting HD video.

The discrepancies in standards is extremely frustrating.  Bottom line, prices, speeds, and capacities are ALL OVER THE PLACE, and can vary greatly from brand to brand, and even WITHIN each brand.

The “best” brand (the one the pros use) in the business seems to be SanDisk.  Their cards consistently meet their published speeds, often exceeding the published speeds (sometimes even doubling speed claims).  Of course, there is always room for error, but this is the card that most people will swear by.

Another popular brand is Transcend, but I think their popularity is largely due to price point, as reviews show that these cards also vary wildly in meeting the published speeds.
I have had good luck (price to performance and cards achieving the advertised speed) with PNY Professional (20MB/s), and others report success with Lexar Professional/Platinum (133x) and Kingston.
UPDATE: My PNY 32GB class 10 fails constantly trying to shoot video with a T3i.

With SD cards the general price rule is around $1 a gig for most brands at the class 4 & 6 levels, and the faster you go, the higher the price. Sometime 32GB cards are a little more than 8 and 16 GB capacities.

“Better” cards like SanDisk Extreme (30MB/s) often doubles this rule ($2 a gig), and going with the “super pro” cards like the Extreme Pro (90MB/s) can triple or quadruple the price, but all the reviews suggest that the price is worth it when shooting HD video.

The CF card you will want should utilize the UDMA (Ultra Direct Memory Access) standard.  Most regular shooters advise getting a SanDisk “Extreme Pro” UDMA 6 card.  This means it can achieve 90MB/s speeds.  However, at nearly half the price, the “Pro” is probably fine at 60MB/s.  Just know that you’re less likely to lose a shot if you spend the cash on the (much) faster card.

You will see Type I and Type II when looking at CF cards.  This corresponds only to physical thickness.  The Type I card is 3.3mm thick, and the Type II card is 5mm thick.

Canon cameras can only shoot clips up to 12 minutes, thus I would suggest having multiple smaller cards is better than having one huge card.  Lots of data on one card means greater risk for loss of all data, and since you’ll never be able to utilize the space for one long recording… go the safer route!

CF adapters are meant to utilize SD cards in devices requiring the CF form-factor.  These will be tempting to users upgrading from devices that utilized SD cards (because you spent a lot of money on fast SD cards and you want to keep using them).  Unfortunately most CF adapters create a bottleneck.  The bus speed of the adapter is nowhere near as fast as the SD cards themselves, thus they prohibit the device from reading/writing as fast as necessary.  Note also that there are Type I and Type II adapters, just like with CF cards (type I and type II).  This corresponds only to size. Type I is 3.3mm thick, while Type II cards are 5mm thick.


Anonymous said...

Great - thanks for your advice!

Anonymous said...

Thanks for your blog. I just shot a job on the Nikon D800 which is brand new. It has both SD and CF slots. I bought 2 Sandisk 16gb SDHC Extreme cards. After about 5 hours of work, the SD card failed! Never happened to me before and this was the first time shooting with SDHC cards. We carried on with the 2nd SDHC card and it failed shortly after! Now I'm really getting frustrated. I had 2 CF cards with some space on it. We ended up shooting again and no issues. Fortunately, I downloaded recovery software and was able to get all the files off the SDHC cards - thank God! So I'm returning the SD cards and going to shoot with Extreme Pro CF cards. One last thing: I don't think I formatted the SD cards before shooting, so it could be that? Not sure. I have formatted the SD cards once I retrieved the data and have been recording onto them to see if they fail again. So far all is normal. If this happens to you - be sure not to try to record on the failed card. Instead try to recover the files. If you do record on them again, you will be re-writing over the lost stuff.

The Invisible said...

Good to hear you were able to recover the data. And yes, always good to put a card on the shelf until you can run recovery options if it fails. Once you use it again, you're writing over potentially recoverable data.

Surprising that the Sandisk cards failed, especially two. I think that's almost unheard of. Not formatting them with the device (i.e. your D800) could definitely have been a contributing factor.

When given the choice between SD and CF, I would ALWAYS go CF. They are just SO much more durable (bigger, sturdier, harder to break), and the transfer technology is also more stable.

I have been using mostly 16GB Extreme Pro CF cards from Sandisk (90MB/s), but recently purchased a Transcend card with the same specs (they say 600x on the front). It was significantly cheaper (about half, at $50 instead of $100 for the Sandisk), and I have been using it with success, but I anticipate the Sandisk cards proving to be more durable (a silicone coating inside makes them dust proof, shock resistant, and water resistant).