Choosing....

Why you might want one:-

Some reasons not to consider one :-

A bit of background - how these cameras work :-

Digital cameras don't use film. Each image is stored as a computer file either on the camera or on a removable memory device.

The cheapest cameras record the number of dots required to cover the smallest workable resolution of a computer screen. This is 640 dots wide by 480 dots high.

Multiplying 640 x 480 equals 307,200. This is the number of pixels (or points) recorded in the image. A MegaPixel is one million Pixels. The cheap camera above, therefore has a rating of 0.3 Megapixels.

More about these megapixels later, in short for now, understand that the higher the megapixel rating, the more detailed the image recorded is. The megapixel rating is the number of pixels that are used to record the image inside the camera.

The most desirable memory is the removable type. This is because if your chosen camera stores all its images on its own internal memory, once its full you cannot take any more pictures until you transfer images to a PC or delete some. If your memory is removable you can always buy a few more 'cards'.

This brings us on to what happens to the images once we have filled our memory or memory cards. Images can be :-

• Transferred to your PC after connection via a lead. Then edit, print at home or at a web based photo lab (eg jessops.co.uk).
• Printed from your memory card directly at a digital lab (nearest one, Asda in Birchwood)
• Memory card images can be transferred to PC via a card reader device

What do I want to use a digital camera for? How many Megapixels do I need?

The table below summarises what Megapixel rating is required for common uses:-

*Sealife Reefmaster DC100 (underwater camera 1.3MP)

**New Canon 11MP EOS 1DS Digital SLR

To print, the above table assumes that images are resized to 200 dpi (dots per inch). The use of larger print sizes will affect print quality.

As can be seen, Megapixel rating and size of image that can be recorded has a major influence on cost. Several 'own brand' and unbranded models are available at discount, but expect well known makes (such as Nikon, Fujifilm, Canon and Olympus to sit within the middle (to the upper) of the above price bands.

Comparison of a 6MP & a 0.3MP images

Notice the vast difference in image size !

Note too that the table above assumes that you are going to print from the full dimensions of the image. If you intend to crop your image then your print size is reduced too. This means that if you are intent on making larger prints, then you may need to consider a larger mega-pixel rated camera.

Digital Cameras above 1.2 Mega-pixel allow several image sizes to be recorded. This is because you may not always want to record images at full size. As can be guessed, lower resolution means that each image takes up less space in memory. Therefore, at a low resolution your memory card can hold more images.

A Raw 640x480 image takes up approx 307K while a 2832x2128pixel image takes up approx 6MB of memory.

Memory comes in various sizes. Usually 16,32,64,128,256 or 512 MB. On a 16 MB memory card, we could hold 52 low resolution images or just two high resolution images if they were stored in this format.

Usually when you purchase a digital camera, the make and model usually determines the type of memory it uses.

Fujifilm / Olympus cameras use Smart Media or xD memory cards

Nikon / Kodak / Casio cameras use 'Compact Flash' memory cards

Sony uses 'memory stick' which is also used in Sony's digital video camcorders. Your new camera will come with a small (if not the smallest!) memory card. Be sure to budget for another £40 (or £65 for Sony memory stick) for an additional 128MB of memory.

So, how many images can I store on my 128MB memory card?

Hold on I hear you say.... "I thought you answered that above?"

Remember earlier, the word 'Raw' was used above.

The answer is not as straightforward as it sounds. A number of factors affect it, including:-

• Capacity of the memory card (in Megabytes MB)
• The Resolution at which pictures were taken (eg 640x480 or 2400x1600 pixels etc)
• The amount of compression applied when storing the photos (JPEG compression number)

Quite often cameras will allow compression level to be set under a 'quality' setting ranging from Hi (Raw/TIF format), Fine (JPEG 10), Normal (JPEG 6), Basic or low (JPEG 3).

Note that using a lower quality setting will store more images on your memory cards, but prints may show some degradation!

Image content has some slight bearing on storage size. I have heard that shop assistants selling digital cameras have come up with rubbish such as "images taken on bright days take up less image space as white doesn't take up as much space". With quality & storage, there isn't really any such thing as a free lunch!

Note the detail in this image compressed at the 'Fine' setting on the Right, and 'Basic' on the left. The former takes up 1MB and the latter only 330KB.

If you have any other equipment (like MP3 players) that use a particular type of memory cards, it might be useful to select a camera that uses the same type so all devices can share the same cards.

What sort of PC do I need and how does the camera connect to it?

Your PC does not need to be of a particularly high specification. It must be at least a Pentium 2 (post 1998), running at least Windows 98 or better, 300 Mhz processor or better, 128 MB of RAM (memory) or higher with a USB (universal Standard Bus) port.

Digital images take up a lot of space. At least 2GB spare on your hard disk drive for storing images is useful and a CD writer drive very useful for storing your images.

The majority of digital cameras link to your PC via a USB lead. Firewire is a new interface type and may need an interface card adding to your PC. If you use an Apple Mac chances are you will already have this interface on your machine.

Some models, notably Kodak and some Fuji models come with a docking station that your camera clips into to download / recharge camera batteries.

You plug it in & your computer sees it as a new 'removable disk drive'

Usually your digital camera will come with a CD of software to help you view, print and organise your images. It is not necessary to have a copy of Adobe Photoshop or an alternative photo editor on your PC, but for in-depth editing and manipulation of your images you may wish to obtain it (or Photoshop Elements which is easier to start with) or similar software. Several photo editors come as shareware or trialware with many magazines as cover CD disks.

Once images have been moved to the PC from the camera, the memory card can be re-used.

A good method of managing your images is to have a folder on your hard disk called 'Images' (or similar) and within that, date each set of images you download to enable you to easily locate images later. From the camera, images will be allocated a sequential number (eg DSCF0045 etc). Be sure to rename / add descriptions to images so they are easy to find later!

Some printers now allow direct USB connection to compatible cameras. This can eliminate a PC completely if image quality is not an issue. One example is the Epson Stylus Photo 935. this connects with Epson and other digital cameras.

What features should I be looking for or be aware of?

Power Sources.

Check expected battery Life. Most digital cameras use AA (or AAA) size batteries, some use an internal rechargeable (Lithium ION low memory effect) battery which is recharged when the camera is attached to a mains transformer. Budget (approx £30 extra) for a spare LION battery or a spare set of high capacity rechargeable MNH type batteries and a charger.

(Lithium Ion Battery) (Ni-Mh AA cells)

Digital cameras are heavy users of battery power. Flat batteries mean that your camera cannot be used. Existing images will be securely stored on its memory card, but only when fresh/charged batteries are inserted can the contents be transferred to your computer.

As can be seen, SLR functionality and a respectable zoom comes at a price.

Other functionality that you may want to look for in a digital camera is listed below:-

Where to see what people think of the digital camera I am looking to buy..

Where to find the best deal

So now you've bought it, some top tips..