Megatest: Memory cards

Memory cards are getting faster and more capacious – but how much speed and space do you really need?

Memory cards are getting bigger and faster, but which ones are better?

In the early days of digital photography, you’d have to spend an arm and most of a leg just to get a memory card with the pace of a snail and a paltry capacity of around 128MB. Today, cards with massively fast transfer speeds of 300MBps or more are widely available, offering cavernous storage of up to 512GB, with even larger-capacity cards on the horizon. One thing remains the same, in that the fastest, highest capacity cards can be fiendishly expensive; so what kind of card should prove adequate for your needs, without forcing you into spending over the odds?

Naturally, digital cameras themselves have come a long way over the last couple of decades. While early DSLRs like the Canon D30 and the Nikon D1 only had around three megapixels,

some of the latest cameras have up to 50 megapixels or more under the bonnet, generating massively larger data files. Recent cameras are also able to shoot 1080p or even 4K UHD movies, really bumping up the need for storage capacity. A single 45-50MP raw file can be around 50MB in data size, and a minute of 4K UHD movie capture can generate around 4GB of data.

If you’re shooting with a 24-30MP camera, raw files will only tend to be around 30-40MB each, and 1080p video capture is relatively low-rent, generally at less than 400MB per minute. With that in mind, a 64GB memory card is sufficient to store around 2,000 raw files or three hours of Full HD movie clips. Cards of this capacity often hit the sweet spot in terms of value for money. We’re therefore testing and quoting pricing for the 64GB capacity of each memory card in this group test, although a wide choice of other capacities is usually available.

From CompactFlash to XQD

The type of memory card you need is, of course, a prime consideration when buying. The once-popular CompactFlash (CF) memory card has largely fallen by the wayside, although it’s still used in some current cameras; most of these are DSLRs with dual slots, which combine CompactFlash with another type of memory card, usually SecureDigital (SD). Originally launched in 1994, the two main categories of CompactFlash are Type I and Type II: the latter is thicker, based on miniature hard drives rather than flash memory. Various updates to the CF standard included the introduction of UDMA 7 cards in 2010. More recently, Video Performance Guarantee ratings have started to be applied, equating to the guaranteed minimum continuous write speed. It’s a ‘need to know’ specification for high-end video recording.

The direct successor to the CompactFlash card is CFast, although in stills cameras it is only currently used as one of the dual slots in the Canon EOS-1D X Mark II. It is neither physically nor electronically backwards-compatible with cameras that have CompactFlash slots. If you need one, the Integral ultimaPRO X2 CFast 2.0 card is a great performer. Write speeds are about the same as in the fastest CompactFlash cards, but read speeds are three times quicker.

CFexpress is the faster future of CompactFlash, and will be available in the same physical format as XQD cards. Speaking of which, XQD was first announced in 2010 by Nikon, SanDisk and Sony. The revised Version 2.0 of the format enables super-fast transfer rates of up to 1,000MBps. Take-up for XQD in stills cameras has been thin on the ground, although they’re in some of Nikon’s high-end DSLRs, as well as its new Z mirrorless cameras. Currently, you’re essentially limited to Sony XQD cards.

SD Card

SecureDigital (SD) is by far the most common type of memory card featured in stills cameras. Small, light and super-slim, these cards were originally launched in 1999, with a maximum capacity limit of 16GB. SDHC cards followed in 2006, with a 32GB limit, and 2009 saw the launch of SDXC cards, with capacities of 64GB and, theoretically, all the way up to two terabytes. Older cameras that have SD Card slots may not be compatible with SDXC cards.

The UHS-I data bus standard, launched a few years ago, increased maximum transfer speeds to 104MBps, while the latest UHS-II standard gives a further potential increase to 312MBps. There’s full backwards-compatibility, so UHS-II cards are fine for use in UHS-I and original non-UHS enabled card slots. However, you’ll need a UHS-I or UHS-II device respectively to use that type of bus card. UHS-II cards tend to be more expensive than UHS-I cards, so there’s no real point buying a UHS-II card if your camera can’t take advantage of it.

The type of memory card you need is, of course, a prime consideration when buying