Just imagine: all the technique we learn and equipment we use comes down to writing a video and/or audio file to a tiny memory card. I get asked to help when things go wrong. I was asked about card problems so frequently in one week near the end of a recent term that I wanted to write what I know in one place. I’ll go into a bit more detail on memory cards in the Sony HXR-NX100 camera, but the principles apply to cards in other cameras, as well as other types of devices, such as portable audio recorders.

It’s really important to get in the habit of following QuickStart and Premiere tech handouts carefully. This info is covered there as well as verbally, so it should not be news.

What can I do to protect my footage on memory cards?

In addition to obvious points about not losing cards or putting them through the washing machine:

  1. Turn off the device before putting in or taking out an SD card.
  2. Let the device finish writing the file to your card before turning it off.
  3. Format memory cards as often as possible in the device you’re going to use them in.

What kind of card should I buy?

Talk with your instructor about this, but I urge the conversation toward multiple SDSDU-016G SanDisk cards. If you can’t find that specific model, at least buy SanDisk 16 GB Class 10 SDHC cards. I’d much rather have two 16 GB cards than one 32 GB card. More on the why of all that below.

The Production Office does not check out headphones, hard drives, or SD cards. If the cost of those items would cause financial hardship, the Class of 1973 endowed a fund for such purposes administered by the Dean of Students Office.

I can just take my card out of a device any time, right?

No! You need to turn the camera off first. (Same goes for audio recorders.) And, when you’re done copying footage from it onto a computer, you need to eject/unmount it before unplugging it, just as you would a hard drive, for all the same reasons.

If you forget once and remove a card while the power’s still on, it probably won’t corrupt your data or damage your card–or maybe it will, first time out. It’s luck of the draw. If it happens enough times, sooner or later: Blam.

Why should I format my cards?

Every time we shoot footage to a card and delete files from it, the card’s storage system gets a little more fragmented. It becomes a little less efficient at writing files. When you format a card, this defragments it, restoring it to peak efficiency as a storage system.

How often should I format my cards?

As often as you can remember. The best habit to get into is this: before you put a card in the camera, transfer all the footage from it and use the camera to format it. Then you know you’re starting with a nice, clean slate. If you never format the card, at some point it will become so inefficient that it can no longer keep up writing your video files properly. Maybe around when final projects are due.

Does it matter what I use to format my cards?

Definitely. Make sure you’ve backed up everything you want from the card first, then format your card in the camera or recorder you’re going to use it in.

Formatting actually does three things:

  1. erases what’s on the card
  2. defragments the card as a storage device, and
  3. sets up a new file structure.

Each device you use a card in needs the card to have a specific file structure.

What happens if my card is corrupted?

A bad kind of randomness has introduced itself to the card so it can’t be read correctly. If just one segment of memory was damaged, maybe you can read some but not all files from it, or maybe the card mounts on a computer but appears to have nothing on it. You should definitely try running RescuePro on the card, SanDisk’s free card recovery tool for macOS or Windows.

Is there anyone else with a magic wand who can fix that sort of thing?

You can email helpdesk@carleton.edu. They have some more tools in their kit–though not endless tools. To appreciate how important the care and feeding of memory cards is, ask Helpdesk staff or the data recovery company SanDisk recommends how much it costs to send something out for full forensic disc recovery… and even specialists can’t always recover data lost in this way.

I’m shooting with a Sony NX100. It’s saying there’s a problem with the database/image management file and would I like the camera to attempt to repair the database?

Short answer: yes, but let your instructor know first.

The camera writes your video to your card but also it writes a tiny database about your footage, listing each piece of footage by name, duration, and so forth. Two things can be damaged: a video file itself or the database. If this database can’t be read perfectly, the camera might act as if nothing can be read at all.

The camera has the good grace to recognize there might be a problem with the database and is offering to repair it for you. If only the database was the problem and the camera can reconstruct it, you’re on track again. If the footage is the problem (and it could be just one last little part of the video file didn’t get written), as Sony Product Manager Ichiro Sudo says, the “NX100 can recover [the] image database file but not the clip itself.” Yohan of Sony’s Imaging Support Program says, “The database recovery message typically appears if the camera was turned off or the card removed while writing. This can also happen when hidden files are left behind after viewing files on a computer, this is why it is recommended to format in-camera before recording.”

Even if the camera tries to reconstruct the image database and it looks like it didn’t work, it’s well worth turning off the camera, taking out the card, putting it in a computer, and asking Adobe Premiere to try importing footage from it. It will import what it can.

What might cause either a video file or database record to be written incompletely?

If a card becomes so inefficient as a storage device that it can’t keep up with the high-speed demand of writing video, file segments are going to get missed in an effort to keep up. Maybe the camera tried to write part of a video to a corrupted sector of the card and couldn’t find a free and uncorrupted sector before it was time to write the next part of the video file. Video files are fussy things that require everything to be just so and don’t tolerate being incomplete.

Camera and card work together to write files quickly, but not instantly. Video files are big, especially long takes. Did the camera get turned off or switched to playback mode, or did the card get pulled, while the camera was still writing a video file? Let the camera finish writing your file.

How often does disaster happen with memory cards?

Depends what kind of disaster. For what it’s worth, in well over a decade of using memory cards of all kinds, I can think of two instances when one simply wore out, both in gear that was in continuous use. One was in a lighting controller after about eight years; another in a piece of digital signage equipment after about three years. So, they are prone to eventual breakdown, but I don’t think that explains any of the shooting/recording card disasters I’ve been asked to consult on.

I’ve lost or damaged a couple but (other than the long-term use cases above) none have failed on me. I attribute this to taking good care of SD cards:

  1. letting the device finish writing the file before turning it off,
  2. turning the device off before removing the card or putting it in, and
  3. formatting the card as often as I can remember in the device I’m going to use it in.

You can make or buy a card caddy to help keep from losing them or putting them through the laundry.

What I really care about is the footage, so I get it off the card and back it up right away, rather than putting it off for later. That hints at a different, totally human error, of potentially formatting a card I haven’t backed up, etc. Taking good care of your SD cards will go a very long way toward none of this happening to you.

Why do you recommend such a specific card?

If all SD cards were equally good for the purpose of recording video and audio, manufacturers wouldn’t bother saying what to use and that they can’t guarantee others will work. If there’s ever tech trouble and a manufacturer needs to be contacted, I want to say I followed their recommendations.

I started with our three main devices: the Sony NX100, Canon C100 mkII, and Tascam DR-100 mkIII, reading each manufacturer’s guidance on SD cards, looking for cards on all three “approved” lists. Sony indicates general requirements for SD cards in the NX100. Tascam lists list specific cards tested in the DR-100 mkIII, as does Canon for the C100 mkII. SanDisk model SDSDU-016G card meets Sony’s criteria and is on both Canon and Tascam’s lists. Here are the details.

Page 26 of the Sony HXR-NX100 manual indicates all but one format it shoots will record to a Class 10 SD, SDHC, or SDXC card, but that its XAVC S HD format (50 instead of 28 mbps) requires an SDXC card.

Page 40 of the Canon C100 mk II manual indicates all formats that camera shoots will record to a Class 10 SD, SDHC, or SDXC card, and refers to a list of specific cards Canon has tested, including the SanDisk Class 10 Ultra SDHC 16 GB (SDSDU-016G-J35).

Page 5 of the Tascam DR-100 mk III manual indicates, without mentioning speed class, that SD, SDHC, and SDXC cards can be used. It does not mention speed class. It refers to a list of specific cards Tascam has tested, including the SanDisk Class 10 Ultra SDHC 16 GB (SDSDU-016G-J35).

Why would you rather have two 16GB cards than one 32 GB card?

I’d like at least one card for each device and, often, we want to shoot video (with reference audio) to the camera and record audio to a portable audio recorder at the same time. You can keep one card formatted for each device and reduce confusion by labelling them. If you’re only using one device, you’ve got a spare card. It wouldn’t hurt to have a third card on hand in case one gets full in the middle of a shoot.

What does Class 10 mean?

It’s a speed rating. Class 10 means something can write to the card at a minumum of ten megabytes per second (10 MB/sec). That’s megabytes, not megabits. (There are eight bits in a byte.) Class 10 SD cards work in all three of our main fleet devices: Sony NX100 and Canon C100 mkII caneras, and Tascam DR-10 mkIII audio recorder.

How does Class 10 compare with the video we shoot? 10 MB/sec is 80 megabits per second (mbps), which you can compare with the data rates in the Sony and Canon manuals. 24 or 35 mbps is a common figure, so you’d typically use less than half the throughput a card is capable of. That’s a comfortable margin to prevent speed-related mishaps.

What’s SDHC?

Secure Digital (SD) cards were introduced early in the year 2000. By current standards, the original SDSC (Secure Digital Standard Capacity) card family was slow and small–the largest would eventually hold two gigabytes (2 GB). (They were also expensive. I found a news release from 2004 announcing a 1 GB SD card with a suggested retail price of $500 which, adjusting for inflation, would be $826 in December 2021 dollars.)

In 2003 and 2004, two new form factors (sizes, basically) were introduced: MiniSD and Micro SD. Both are ideal for cell phones, but not used in shooting video or recording audio.

In 2006, faster, bigger SDHC (High Capacity) was introduced: up to 32 GB. In 2009, SDXC (Extended Capacity) was introduced, with capacities up to two terabytes (2 TB). In 2019, SDUC (Ultra Capacity) was introduced–up to 128 TB. Documentation for neither Sony NX-100, Tascam DR-100mkIII, nor Canon C100mkII mentions SDUC cards.

All are available in the marketplace today, and any of them might be referred to generically as “SD cards” so when shopping, it’s important to double-check whether you’re about to purchase SDHC cards. The fact that SDHC as a card family was introduced before the iPhone, doesn’t make it old and bad. It is fast and capacious enough to record the digital video and audio we do.

What about shooting in the very highest bit-rate format the Sony NX100 can shoot?

What if it’s not that important? The second-highest bit-rate format the NX100 is capable of is terrific for introductory assignments, which is what that camera is used for around here. But, if you wanted to, you definitely would need an SDXC card. I put an SDHC card into the NX100 and chose XAVC S HD, its highest bit-rate format (50 mbps). When I pressed the record button, the camera showed an error message letting me know it wouldn’t even let me try to record that format of video to an SDHC card.

What do memory card model numbers mean?

I was asking Harold of SanDisk Global Customer Support about two cards that had very long model numbers identical but for the last three characters: -JU3 and -J35, they happened to be. He said, “…the Part numbers are technically [the] same and there is no difference in performance or specification between the two. However, the suffix part JU3 or J35 of the part numbers are the region codes designed by the marketing department for distribution and marketing purposes…” Good to know while shopping.

Won’t other cards work?

Some will. It really matters at troubleshooting time to be able to tell a manufacturer, “I followed your memory card recommendations.” Canon and Tascam each list lots of other cards they’ve tested in our two devices, and plenty more meet Sony’s broad requirements for NX100. And you could have different makes and models of cards for different devices, although that would introduce needless complexity.

How much does this card you’re recommending cost?

As of January 2022, the SDSDU-016G was available for as little as $6.79. It’s possible to inadvertently pay a good deal more than that for an off-brand/no-name card.