Cave Cardem

OK, that is rather a lame wordplay on the Latin “Cave Canem”, which means “beware of the dog”. So I mean “beware of the (wrong) memory cards”.

How so?

Bit of background. I always use only Sandisk or Lexar cards – they do work more reliably. And my images are important since I get paid for them, so why try to save? Better is, well, better. That does not mean I buy fast or large cards – but I buy brand names only.

So. My second shooter used an 8GB eye-fi card in her D90 camera the other day to shoot a wedding. This is a card that can connect to WiFi, but it also writes to local storage.


The moment I inserted this card into my card reader, my iMac crashed. Hard. Grey screen of death. That happened twice. And now the card is unreadable on any machine.

Or not?

Part of a wedding is something you must never lose. And yet this happened. Perhaps Eye Fi ( can help restore the images? Perhaps, but so far, over 24 hours later, they have not responded to my email support request.

And this, my friends, is why I use only Sandisk and Lexar cards. And cameras that write to two cards at once (my 1Ds Mk3 and 1D Mk4). Live and learn, never again will I allow anyone who shoots with me to use anything except a freshly formatted Lexar and Sandisk. If your images are of equal importance to you, you will do the same.

And the wedding? Well – that is why we have two shooters and four cameras (with another in the car as a backup). The wedding couple will be happy. But I am not.


Card Speed

A question I get often is “what memory card speed do I need”. The ratings are confusing and the offering even more so. So this is a good question. A reason to explain card speeds.

I have explained before why and when you need fast cards (in short, when you shoot high-def video, when you shoot sports, and when for simple convenience you want to be able to review the pictures on the back of your camera as quickly as the camera will allow).

But what do the ratings mean?

  1. CF Card ratings. The original CD-ROM had a transfer rate (“how fast can data be moved off the device?”) of 150 kByte/second. That is what we call “1X”. So 10x = 1.5 MByte/second, and “40x” means “6 MByte/second”. This is how CF cards are rated.
  2. CD card ratings. These are usually rated as a “Class”. This expresses the minimum transfer speed in MByte/sec, so class 6 means 6 MByte/second.
  3. Manufacturer ratings. Oh, well, these are mainly (but not all) marketing. “Extreme this or that”. You need to Google these and translate them back to real numbers.

Be aware of a few things.

  • Just like Megapixels, a simple number does not tell the whole story. Is the data rate continuous or “burst”? Does the card do more error-checking and correcting while it is doing the transfer?
  • And be weary of large sizes: if you lose a 16 GB memory card due top failure or theft, you lose hundreds or even thousands of pictures all at once.

Michael’s tips: Buy a few good brand-name memory cards (Sandisk and Lexar are the class leaders). Own at least one fast card. For hi-def video, you need a class of at least 6 (6 Mbyte/sec).

Memory cards Q&A

A quick Q&A note about memory cards today.

Q: How many of them do I need?

  1. Get many.
  2. Get more.
  3. Now get more.

Memory cards, I have said for years, are just like baskets. Photos are like eggs. Need I say more?

Q: Do I need fast cards?

Not necessarily. For video and for fast shooting as in sports a fast card is needed. For everything else, there is little need. Fast cards are convenient (faster review, faster writing of the buffer) but not necessary.

Q: Should I buy brand names?

Yes. Lexar, Sandisk, etc are in fact electronically better.

Q: What size?

It depends. I like 16 GB for the big cameras but only because I can write to two cards at once, and because my big cameras write big files. Normally I would say 8-16 GB, no larger.

And when travelling, 4GB cards. Why? Because a 4GB card will write in its entirety to a DVD. An 8 GB card, on the other hand, has to be written to two DVDs which will increase the confusion factor.

Take care of your memory.. and memories

A regular reader asks:

Good morning Michael,

I’m going on a 2 week vacation soon, and am thinking about how I manage the cards to keep my risk as low as possible. I plan on nightly backing up the cards to a laptop and to usb sticks. I won’t be deleting any pictures off the cards until I get home (if at all possible). This way I should have 3 way protection. A little crazy, but we’re dropping 10k into this. I don’t want to lose anything. My big worry would be losing the camera bag and laptop due to theft. The usb sticks will always be kept on me or in a different location at least.

Anyway, I’ve a question about handling memory cards. I have always left them in the plastic containers they came in and then put them into slots in my camera bag. I find that cumbersome, but I don’t want to damage them. These are SD cards if that matters. Is it okay just to forget about the plastic cases and tuck the cards into the elastic slots? What about card cases? Do you have any recommendations?

Thanks for any thoughts. I’ve been enjoying your down to earth photography discussions.

Thanks for the compliment, and yes, I have some thoughts:

  • First, the idea of backups makes a lot of sense to me. Things fail and get stolen. I always keep backups, multiple backups if possible, while travelling.
  • If a laptop is big or expensive, consider a Netbook and external drives. A netbook is useless at most things but great for things like backing up pics from an USB-mounted card to an external drive or two – and they’re cheap.
  • I like 4 GB cards. Why? Because they avoid “too much on one card” and because a 4GB card fits in its entirety onto a DVD! Then you can burn DVDs (or go to a camera store to have it done) and mail yourself a copy at home. That’s real safety. And a DVD costs just a few pennies.
  • Cards in the bag without cases is fine – I do that too, as long as the bag is not a flexible type you will sit on. Camera stores sell little card-wraps/containers; many of these have a clip you can use to secure the container to your camera bag. This is an essential step.
  • After backing up a memory card, before reusing it always format it – and in the camera. It does not have to be a low-level format – but I do that too every now and then, just to keep the card fresh.
  • Avoid 800 pictures of Rome on one card. Someone grabs your camera: the pictures are all gone. I swap cards regularly whether I have to or not.

Finally: shoot RAW so you can save sub-optimal pictures, and bring a lot of memory. Your $10k is ephemeral: it is gone as soon as the trip is over – but by securing the trip in pics that $10,000 becomes a lasting investment. That’s worth some extra memory cards!