Tuesday, April 12, 2011
Misinformation: Camera Tech
Size isn’t the only major feature of a memory card
The megapixel wars used to be the driving force behind ever-expanding capacities, and while that battle has more or less evened out, memory card capacities are still increasing, thanks primarily to the newly incorporated video capabilities of DSLRs. This also is due, no doubt, to Moore’s Law, which dictates that computers and the myriad technologies driven by conductive materials, in particular memory cards, will double capabilities every two years. This implies that product bought only two years ago will be half as effective as today’s products, and one only need to look at the ever-topping-themselves maximum capac-ities of modern memory cards to validate the theory.
Myth: Bigger Is BetterCompanies now are offering cards that measure in at astounding sizes, currently topping off at a massive 128 GB with CF cards and 32 GB for SDHC, as well as a theoretical top capacity of 2 TB with SDXC cards. (The highest capacity for SDXC cards is “only” 128 GB at this time.) While maximum read and write speeds have increased, as well, it’s often the minimum that’s most important to pho-tographers and videographers. With DSLRs that currently max out at 10 fps for bursting, the redundancy of these almost ridiculous levels of speed comes into question. (Video requirements are all over the board, depending on codec, bit rate and type of video. “Sustained” read and write times, which are different than “maximum” read and write times, are the most important spec when it comes to video.)
Companies that work with superconductors are extremely smart, and they’re aware of the direction in which their products will be most effective. The evolving capabilities of memory cards can reflect advancements in technology before the rest of the market even catches up. Available in SDXC and SDHC cards, the UHS-I standard employed in newer cards by Kingston, SanDisk and others, for example, offers possible transfer times of up to 104 MB/s. This translates to images and files that can be read at up to 60 MB/s and written at up to 35 MB/s with approximate speeds of 233x. The only camera currently compatible is the Nikon D7000, though the cards are backwards-compatible. (The announced but as yet unavailable UHS-II provides up to a theoretical 312 MB/s.)
So why are these cards available on the market if they’re actually too good for the products they’re designed for? Because times change. Memory cards used to offer one thing and one thing only, an efficiently designed storage device for the writing and transferring of digital files between common devices. As the convergence between photography and video continues, memory cards are offering more than ever before, including wireless capabilities and, in the case of the UHS-I format, a source that has enough transfer times to allow streaming of large video files, potentially providing a workflow that lets editors work with files that are still on the card. The UHS-I pipeline also would allow continuous high-burst still capture that exceeds current camera levels (but not future burst rates!), video-clip recording of files that are over 4 GB, thanks to the exFAT file system, and interestingly enough, enough "broadband" room to allow a variety of tasks to be performed simultaneously, or in other words, a card capable of multitasking, similar to a hard drive.
Will every photographer need these capabilities? Nope. Will every photographer need such huge capacities? Some photographers will, and some won’t. Just as with cameras, computers, cars, clothes and other commodities, memory cards now are available with a variety of features, speeds and sizes, and which cards you choose to purchase might be a matter of taste, need and economics. The uniform days of one similar product offered by a variety of companies at fairly congruous pricing might simply be over, making memory cards as much a buying decision as any other comparison-shopping experience.