• Minimum of 3 Megapixels resolution
• Large LCD preview/review screen
• Replaceable and/or rechargeable batteries
  (digital cameras are power hungry)
• Removable memory card with fast write speed
• A lens with a zoom range of x3 or greater
• Multiple exposure modes with manual override
• Built-in, full feature flash

Broadly, there are three types of camera that should be considered: a basic point-and-shoot model that will fit into the shirt pocket or hand bag, an upper mid-range and beyond all-in-one compact model that looks a bit like an SLR, or a full single lens reflex (SLR) system, either amateur or professional. The factors will depend on your budget, level of photographic experience and what you want to use the images for.

The compact model is a very versatile beast, being lightweight and portable. It could be used on holiday as well as for business.

Some compact models at the top end of the market work like SLR cameras, letting you frame your picture through the lens rather than via a viewfinder. This is very helpful for close-up and macro work. This class of camera is sometimes referred to as 'prosumer'.

A true SLR system is for the experienced photographer. Different lenses can be fitted to the digital camera body and they offer the most control over the image. Digital SLR cameras also record the image in a special 'loss-less' file format called RAW. This records all the image information and allows the user to manipulate the image on a computer using special software without loosing any image quality.

If you already have a 35mm SLR system, it may be worth considering a digital camera body from the same manufacture, as in many cases your existing lenses will be compatible with your new body. However, there is one important difference. Only the very top of the range models are likely to have a full 35mm sized (36 x 24mm) charge-coupled Device (CCD), the component in the digital camera that captures the image. Most will be smaller and the effect of this will be to extend the focal length of your existing lenses by a factor governed be the ratio of the CCD/35mm size difference. See Lenses for more information. link..