Most cameras, even the entry level 3.2 megapixel point-and-squirt cameras, take pictures that range from acceptable to excellent. However, there is one fundamental feature that separates the good from the bad in digital cameras and that is the viewfinder.

It is wrong to assume that if the camera has a Liquid Crystal Display screen on the back then that is all that is needed. There are a number of cameras that have no other method of framing and composing pictures -- the Canon Ixus i , the Olympus AZ-1, Pentax Optio MX and the Nikon Coolpix SQ are cameras recently tested by dpexpert that have only LCD screens and no optical viewfinder.

LCD screen images become invisible in bright daylight, so framing and composing with these cameras is sheer guess work. These little cameras are all fashion accessories intended for use at parties. Any camera that has only an LCD screen and no optical or electronic eye-level viewfinder cannot be taken seriously as a general purpose camera.

In the expensive 8 megapixel range of cameras from Canon, Olympus, Sony, Minolta and Nikon the viewfinders are all electronic devices, much the same as those used in video cameras. The view is displayed on a tiny video screen with low resolution and poor brightness and contrast rendition. At least they are useable in bright light, but the resolution of the viewfinder screen is so crude that they cannot show much more than the general framing of the shot.

There is another problem with the current crop of electronic viewfinders -- they appear to be related to intolerable shutter lag. The image is read from the camera sensor, converted into a video image, sent to the viewfinder and rendered on the screen. When the picture is composed and the shutter release half depressed to set focus and exposure the image that is seen in the viewfinder is a fraction of a second behind the picture that the camera takes. dpexpert finds these camera types to be frustrating, particularly when following a fast moving subject.

The best viewfinders are in single lens reflex cameras, using an arrangment of prism and mirror in the better SLRs and all-mirror systems in the lesser models. SLRs don’t even display the image on the LCD screen before taking it. They eschew gadgetry.

For those not wanting to pay the high price of a SLR or preferring the portability of the all-in-one zoom camera there are alternatives in good optical viewfinder cameras from Canon, Sony and Pentax.

These cameras have LCD screens and the Canon G6 has a swivelling screen which can be useful. Canon’s cheaper Powershot A95 also has a swivelling LCD, but the Powershot S70 is fixed. All three cameras have excellent optical viewfinders, as does the Olympus 5060 which is in the same price/quality range as the Canons.The Sony DSC-V3 is a particularly fine, if somewhat expensive, camera that we recommend highly. The Pentax Optio 750Z is also an excellent viewfinder camera.

The G6, Sony and the Olympus 5060 have the added refinement of dioptre adjustment to fit the viewfinder to people who are long or short-sighted.

Optical viewfinders generally have one small drawback -- they don’t show the entire image that will be captured by the sensor. Typically they show between 70 and 85 per cent of the picture. It means that there is some guesswork in framing a picture to fill the entire image area.

Cameras with optical viewfinders tend to have shorter shutter lag times. Note the qualifying “tend to”.

A single lens reflex gives the best, most accurate view of the image. Next best is a good optical viewfinder with dioptre adjustment. After that any camera with a good, bright, straight-through viewfinder is better than any camera with no optical viewfinder at all. Electronic viewfinders are, as one wag has decribed them, “designed by video game players for other video game players”.

So, our advice to buyers is hold the camera, check the viewfinder and give it high priority in the criteria of choice. A 4 megapixel camera with an optical viewfinder is almost always better than a 5 megapixel camera without one.

*