Tag Archives: card

SD Cards – how long do they last?

This came up on facebook the other day, how long do SD cards last?

First of all – I have found SD cards to be pretty reliable overall. Not as reliable as SxS cards or XQD cards, but pretty good generally. The physical construction of SD cards has let me down a few times, the little plastic fins between the contacts breaking off.  I’ve had a couple of cards that have just died, but I didn’t loose any content as the camera wouldn’t let me record to them. Plus I have also had SD cards that have given me a lot of trouble getting content and files off them. But compared to tape, I’ve had far fewer problems with solid state media.

But something that I don’t think most people realise is that a  lot of solid state media ages the more you use it. In effect it wears out.

There are a couple of different types of memory cell that can be used in solid state media. High end professional media will often use single level memory cells that are either on or off. These cells can only store a single value, but they tend to be fast and extremely reliable due to their simplicity. But you need a lot of them in a big memory card.  The other type of cell found in most lower cost media is a multi-level cell. Each multi-level cell stores a voltage and the level of the voltage in that cell represents many different values. As a result each cell can store more than one single value. The memory cells are insulated to prevent the voltage charge leaking away. However each time you write to the cell the insulation can be eroded. Over time this can result in the cell becoming leaky and this allows the voltage in the cell to change slightly resulting in a change to the data that it holds. This can lead to data corruption.

So multi level cards that get used a lot, may develop leaky cells. But if the card is read reasonably soon after it was written to (days, weeks, a month perhaps) then it is unlikely that the user will experience any problems. The cards include circuitry designed to detect problem cells and then avoid them. But over time the card can reach a point where it no longer has enough memory to keep mapping out damaged cells, or the cells loose there charge quickly and as a result the data becomes corrupt.

Raspberry Pi computers that use SD cards as memory can kill SD cards in a matter of days because of the extremely high number of times that the card may be written to.

With a video camera it will depend on how often you use the cards. If you only have one or 2 cards and you shoot a lot I would recommend replacing the cards yearly. If you have lots of cards either use one or two and replace them regularly or try to cycle through all the cards you have to extend their life and avoid any one card from excessive use which might make it less reliable than the rest.

One thing regular SD cards are not good for is long term storage (more than a year and never more than 5 years) as the charge in the cells will leak away over time. There are special write once SD cards designed for archival purposes where each cell is permanently fused to either On or Off.  Most standard SD cards, no matter how many times they have been used won’t hold data reliably beyond 5 years.

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Sonnet EchoExpress Thunderbolt Adapter SxS Speed Tests.

IMG_1165-300x224 Sonnet EchoExpress Thunderbolt Adapter SxS Speed Tests.
Sonnet EchoExpress

I have had this little box for a couple of months now, but until the recent release of SxS drivers by Sonnet you couldn’t use it as an SxS card reader. There are two versions of the EchoExpress, the standard one, which is the one I have and a “Pro” version that offers higher speed transfers when using PCIe 2.0 adapters. When Apple removed the express card slot from their MacBook Pro laptops, they severely restricted the ability to connect high speed external hard drives. I have a Convergent Design Gemini which records on to SSD’s and the fastest way to offload these on location (for me at least) was to plug an eSATA PCI Express card into the slot on may older MacPro and then connect the Gemini Docking station to one port and then an external eSATA drive to the other. However, the processing power on my older MacBook was falling somewhat behind the modern machines and when trying to transcode from the uncompressed Gemini DPX files to ProRes or DNxHD was taking ages. So I decided to upgrade to a new MacBook Pro, but this then meant the loss of the Express Card slot. This is where the Sonnet EchoExpress became a “must have” add on, as it provides an external ExpressCard slot connected to the computer using Thunderbolt.

By using the EchoExpress box along with a Sonnet eSATA express card adapter I can connect eSATA devices to my MacBook Pro. The transfer speeds with my original version EchoExpress are not as fast as when I had a built in ExpressCard slot, but it’s still a massive improvement over USB, about 4 times faster. Initially SxS cards didn’t work with the EchoExpress, but Sonnet recently released a dedicated SxS driver that allows the EchoExpress to work as a SxS card reader.

So how fast is it? One thing to consider is that when using the EchoExpress as a card reader, on a MacBook Pro or 21″ iMac you only have a single Thunderbolt port, so there is no way to connect a second EchoExpress to add an eSATA port. That restricts you to using either the computers internal drive or an external Firewire 800 drive. For my tests I made copies of a full 16Gb Blue SxS card to both the internal drive as well as an external Seagate GoFlex FreeAgent drive fitted with a Firewire 800 interface.  There was very little difference between the transfer speeds to the laptops internal drive and the Firewire drive, so I suspect that the transfer speed is limited to that of the Sonnet EchoExpress.

Copying 16Gb from the SxS card via the EchoExpress took just a shade over 4 minutes. That’s pretty good performance and only marginally slower than when I had an express card slot built in to the computer. Typically with a built in slot it would take about 3 1/2 minutes. Compare that to copying the exact same data from the camera using USB which took 11 minutes! So, as an SxS card reader the Sonnet EchoExpress works really well offering transfers around 3 times faster than USB which is a big time saver. Imagine you have been shooting all day and have 5 hours of footage. With USB it would take you at least an hour to transfer your data, with the EchoExpress just 20 minutes.

I give the Sonnet EchoExpress a big thumbs up. Now all I need is a Thunderbolt hub.

Sonnet SDHC to SxS Adapter Review.

I recently reviewed the rather excellent Sonnet QIO I/O device that allows you to very quickly ingest material from SxS cards, P2 cards as well as SD cards to your computer. Along with the QIO I was sent a Sonnet SDHC to SxS card adapter to take a look at. Now I’m going to lay my cards on the table here and say that I strongly believe that if your going to shoot with an XDCAM EX camera you should be using SxS cards in order to get the best possible reliability. However as we all know SxS cards are expensive, although a lot cheaper now than they used to be, I remember paying £600 for an 8Gb card only 4 years ago!

So ever since the launch of the XDCAM EX cameras, users including me have been trying to find alternative recording solutions. I found that it was possible to use an off-the-shelf SD card to express card adapter (the original Kensington Adapter) to record standard frame rates on class 6 SD cards in the EX cameras.  However the SDHC cards stick out of the end of the generic adapters so you can’t close the doors that cover the card slots in the cameras. Following that initial discovery various companies have brought out flush fitting adapters that allow the use of SDHC cards. Then about two years ago Sony openly admitted it was possible to use an adapter in the cameras and released their own adapters (MEAD-SD01 and MEAD-MS01) as well as making some firmware changes that made using adapters more reliable. The key point to consider when using an SxS adapter and SD cards is that the media, the SD cards, are consumer media. They are produced in vast quantities and the quality can be quite variable. They are not made to the same standards as SxS cards. So I choose to shoot on SxS whenever possible and I’ve never had a single failure or unexplained footage loss. BUT I do carry a couple of adapters and some SD cards in my camera kit for emergencies. You never know when you might run out of media or find yourself in a situation where you have to hand over you media to a third party at the end of a shoot. SDHC cards are cheap and readily available. You can buy an SDHC card just about anywhere. I’d rather switch to SDHC cards than try to do a panic off-load to a backup device mid-shoot, that’s a recipe for disaster!

Sonnet-SxS-300x295 Sonnet SDHC to SxS Adapter Review.
Sonnet SDHC adapter for SxS Camera Slot

Anyway… on to the Sonnet SDHC to SxS adapter. It feels as well built as any other adapter on the market. It is mostly metal with plastic end pieces that are made from a nice high quality plastic. I have other adapters that use a very brittle plastic and these can break quite easily, but this one appears to be well made. The SDHC card slots into a sprung loaded slot in the end of the adapter making a reassuringly positive sounding click when it’s latched in place. Once inserted the SDHC card is slightly recessed into the adapter. This is good as it helps prevent the SDHC card from being released from the adapter as you put the adapter into the camera. It means that as you push the adapter into the camera you are pushing on the end of the adapter and not on the SDHC card like some other adapters I have used. To remove the SDHC card you simply push it quite firmly, further into the adapter until you hear another click and it then pops out far enough to be pulled out. This is certainly one of the better made adapters that I have come across.

To test the adapter I used some Transcend class 6 SDHC cards as well as some Integral Ultima Pro class 10 SDHC cards. I used the adapter in my PMW-F3 with firmware version 1.10 as some user have reported problems with other adapters and this firmware revision. I was able to completely fill the cards shooting using S&Q motion at 50fps or 60fps using long and short clips with lots of motion. This is I believe the toughest test for these adapters as the recording bit rate is close to 70Mb/s. I had no issues at all with either type of SDHC card and there was very little delay between finishing a recording and being able to start the next, a good indicator of the cards high performance. I also tested recording very long clips to ensure that there would be no issues when the camera breaks the recording into 4Gb chunks. Again, no problem.

So if you are going to use SDHC cards and an SxS adapter I would suggest you consider the Sonnet SxS adapter. It’s certainly cheaper than the Sony adapter. Sonnet are a large business with a wide range of products and a global distributor and dealer network, so you should have no problem finding a local supplier.