Читать книгу Collins Complete Photography Manual - Collins Dictionaries - Страница 30

Memory cards come in several different types. These are SD (Secure Digital), CompactFlash, xD Picture Card and Memory Stick. There is also an older ‘Smartmedia’ format which is no longer in use.

All these types offer broadly similar value for money and performance, so you do not need to choose a camera based on the type of memory card it uses, unless you already have a stock of memory cards or you already have another camera and you want to stick to the same cards.

Memory cards vary in storage capacity. This is measured in megabytes (Mb) in the same way as computer storage. You will typically get 16Mb or 32Mb supplied with the camera, but this is not sufficient for longer photographic assignments. Each digital photo will take up around 2-4Mb of space and, if you use a digital SLR to shoot RAW files, these can take up 5-25Mb, depending on the camera.

You should consider buying a 256Mb card at the very least, since this will be enough for around 100 shots with an average compact digital camera. However, 512Mb and even 1Gb (1000Mb) cards are also comparatively inexpensive, and letyou take many more shots.

Some memory cards are marked with a speed rating (for example ‘40x’). This describes the speed at which the card can store the image data supplied by the camera. However, the processing hardware in the camera is usually the main bottleneck. High-speed cards can offer better continuous-shooting performance or longer movie sequences in some instances, but in most cameras the advantages of’fast’ cards are minimal.