Copyright Michael Karbo, Denmark, Europe.
Chapter 12. Memory cards
Digital photographs consist of data, which has to be stored. This can be done on many types of media such as hard disks and CDs, but in a camera, as room is restricted, flash RAM is preferred.
RAM is an electronic component that can recall data. It is used in large amounts in computers but is also found in mobile telephones and all sorts of other electronic industrial products. But contrary to the usual RAM known from computers, flash RAM works when the camera hasn’t any power. The storage works both when the camera is switched on and when it is switched off (just like a hard disk does).
Flash RAM is in all ways a practical invention and very suitable for use in a digital camera. The only problem being that it is found in several different formats, which don’t fit into the same camera. There are many different types of memory cards – how are they different? And how big should a card be?
Figur 40. Three popular types of memory cards for cameras. At the top is a CF card, under that an xD- and an SD-kort.
Storage capacity on memory cards
Most cameras are supplied with a little memory card, typically of just 16 or 32 MB. This is great – so you can begin taking photographs immediately. But the card is not nearly big enough – you need 128 MB, 256 MB or more. Luckily, flash RAM is under fast development; the electronics becoming every year smaller, faster and cheaper, to it will be economically affordable for most people to buy a suitably large memory card.
The case is that with lots of room on a memory card, you take more photographs; it’s as simple as that. And this is exactly what you should do; take a lot of images – especially in the beginning. Because that’s the way to learn most effectively!
As a rule of the thumb a memory card should have enough room for at least 100 photos in the camera’s best resolution. A hundred images are quickly taken when you get going. The individual exposures don’t cost anything; the idea is to just keep on taking photographs.
So there has to be plenty of room on the memory card or else you can have an extra card in reserve. It’s not reasonable if you have a good camera, which can take photographs “free of charge” and at the same time have a storing capacity, which restricts you.
The table shows how many exposures you can roughly have on different sizes of memory cards with different resolutions. The calculations are based on average JPEG compression with the quality ”Fine”, and make it easy to find the right size of card for your camera.
If you use the more advanced types of file formats (like RAW and TIFF), you will require even more capacity. So there is no reason to practise economy with memory cards.
Figur 41. The size of the memory card should fit in with the image files’ resolution. You can see here how many exposures can be stored on a memory card when they are taken in the next best JPEG quality (”Fine”).
Several types of flash-RAM
So it’s a good idea to have a fairly large memory card for your camera. There should be enough room for at least 100 exposures (twice as much would be a good idea), and this means a card with a size of 256 or 512 MB. But what about the different types of memory cards that are to be found on the market?
Different manufacturers use at the present four types of flash RAM. Generally speaking the cards can do just about the same things. The difference is in the size of the cards, their price and their names. The three most important formats are Secure Digital, XD-Picture and CompactFlash. Or SD, xD and CF, as they are usually called.
The SD and xD format cards are very small and light; and are, therefore, mostly used in the smallest cameras. CF cards are big, robust and cheap, so they are used in most of the cameras that are a little larger.
Sony has developed its own format called MemoryStick; which hasn’t, however, been broadly used in other than Sony’s own cameras. Finally, older cameras have memory cards in the formats SmartMedia and MMC/MultiMedia, but they are, in fact, no longer in production.
The safest choice is a camera, which accepts CF cards. This is the cheapest and most widely spread memory card, which at the same time is robust and can be used in nearly all brands of camera. So it is seldom a bad buy.
There is often enough room for two memory cards in the
larger camera bodies. Sony’s biggest camera has room for both MemoryStick
and CF cards. Similarly some
Figur 42. Standards for memory cards.
Figur 43. There is enough room here for both the little and fast XD card and the robust and cheap CF card (Olympus 5060Z).