The memory card you already know you have purchased for your camcorder, extend the storage capacity of your camera, your smartphone or tablet. Storage is not the only criterion, the performance can be crucial. Review of main reasons to buy a high performance SD card.
Choosing the memory card is not as easy as it seems. There are two main criteria: the storage and performance that gave rise to a new range of cards.
Today, flash memory card format most commonly used is the SD (Secure Digital) and its smaller variants, mini SD (almost gone now) and micro SD. For each of these three formats, there are variations depending on the capabilities: SD (128MB to 2GB), SDHC (2GB to 32GB) and SDXC (32GB to 2TB). Attention formats are compatible in a sense, but not in the other, an SD card works on a SDHC reader, not the opposite.
A brief history of SD card
Memory cards are also distinguished by their performance, that is to say the rate in reading and writing guaranteed minimum. To differentiate, many resources are available through the sheet that is included. The most common is an even number surrounded by a C. This is the “classes”. There are four: 2, 4, 6 and 10 the larger the number, the better the performance. The meaning is simple: class 2 for a write rate of 2 MB / s Class 4 4MB / s, etc. Recently, two other classes have emerged, they are called UHS. These U1 and U3 class, first one is equivalent to class 10, while the second offers a rate of 30 MB / s. Note that the information is a minimum guarantee. They do not express the performance in real situations.
Another sign, closer to real performance, appear on recent maps. There is a Roman numeral “I” or “II”, which corresponds to the version of the interface. “I” is the UHS-I bus, which offers up to 50 MB / s write and 104 MB / s read. “II” meets the UHS-II bus that offers three times better performance. If no number is shown, then map based on previous bus speed provide maximum performance of 25 MB / s.
The price of a memory card varies from a few euros’ more than a hundred euro’s. The price increases not only as a function of the capacity, but also of the class. An example: a SanDisk microSDHC 32GB card costs € 17 in Class 2, Class 4 20 euro’s, 25 euro’s for class 6 and forty euro’s for class 10.
All cards are based on the technology of flash memory. If this format is less sensitive to shock than conventional mechanical hard disk, it remains sensitive to temperature, humidity and magnetic fields. The number of write and erase cycles is limited and some cards do not handle well wear. This exposes your content to the risk of fading. It is therefore important to remember that a memory card is a temporary storage space.
However, it is minimal risk that should not stop you from investing in a high performance card if your uses require this type of support. Here are five reasons that should be enough to convince you:
I – Photo size that matters
If you have invested in a digital SLR, you may have chosen to set your camera to save photos in RAW format. Each snapshot weighs about twenty MB. The operation of a camera is special: when the sensor snaps, it captures in a very short time the light, analyze information and transfer directly to the memory card. This process is extremely demanding on the map. If she does not write fast enough information sent by the image processor, some information may be missed. This will corrupt the picture and render it unusable.
II – Cadence burst mode
Also in the field of digital photography, you must have a burst mode. While every photo is saved in JPG format, the operating mode of a camera is the same: the image processor sends all images on the card. The flow must be sustained and sufficient for each photo.
III – New video formats, new needs
For Video, high performance card is equally important. If the task is less demanding than in the picture, it becomes increasingly difficult as the image resolution and frame rate are important. The flow of information in a video in Full HD is between 10MB / s and 40MB / s depending on the image quality, content and refresh rate. In 4K / Ultra HD , the flows are doubled or even quadrupled. For these definitions video, a UHS card is highly recommended. The risk here is also losing entire sequences. If a portion of the file is corrupt, the whole film is unusable.
IV – Access and work faster its images
Once the video is done, you may modify or cut directly on your smartphone or APN want. Again, the flow in reading and writing are important, first for a matter of time, each operation hogging resources, then as a matter of autonomy.
V – Who can do more can do less
Watching a video in Full HD and 4K is generally easier for a memory card, because the write speeds are always higher than those in writing (the ratio is about 1 to 2). Not however forget that flows to watch a video in full HD up to several tens of Mb / s. If the card is too slow, you will have stuttering on the screen that will make viewing difficult.