A Short Piece for MacUser (UK edition) 9 June 1995

by John Henshall

Colour pictures are created in the Kodak cameras by dyeing each CCD element red, green or blue and then calculating colour temperature from the difference.

Mark Twain defined a crank as 'a man with a new idea - until it catches on'. The first proposal for a workable system of electronic photography was put forward as long ago as 1908 by Alan Archibald Campbell Swinton, 'a crank' with an impossible dream Despite its immense electronic complexities, Campbell Swinton's idea took only twenty four years to become a reality as the world's first system of electronic photography - before the Second World War.

The camera was completely electronic, producing images without any mechanical assistance apart from focusing. The system enabled images to be sent from point-to-point by cable, or through the ether using invisible waves. All this was accomplished instantly - at the speed of light. The process produced twenty five electronic images every second and was true multi-media, being accompanied by synchronised sound.

The system is still around today. Colour has been added, many refinements made, but basically it is still the method which Campbell Swinton proposed almost ninety years ago. We all use it and take it so much for granted that it is easy to forget that this was the first workable system of purely electronic photography.

It is called television.

Television has had a significant effect on computer imaging. The reason computer monitor screens have a landscape format 4 to 3 aspect ratio is because they use television cathode ray tubes. Despite all the advances in computers over the last ten years, we still spend most of our time producing portrait format documents on landscape format tv tubes. OK, so a few use Radius' (now Portrait Display Labs Inc's) Pivot monitors. But even they are the same tv tubes, turned on end.


Twelve years ago, television had a profound effect on photography. Sony shook the photographic world by launching Mavica - the magnetic video camera - a camera for still photography which had a revolutionary difference: it did not use film.

Photographic manufacturers thrive on making consumables - film, photo-sensitive paper, processing chemicals and so on. Any move away from this is a threat to their business as a specialised chemical plant. Mavica alarmed photographic manufacturers, who had two alternatives: start research on electronic photography products, or face decline.


In many ways, Mavica was just another Sony television camera, for the pictures it produced were television pictures. But instead of twenty five television pictures a second (in Europe) or thirty (in Japan and the USA), Mavica produced single frames of video - a video still camera. 'Video stills' is almost a contradiction in terms: the camera produces video pictures which, taken as individual frames, are still pictures. In place of film, Mavica recorded still video images on a two inch floppy disks - looking just like miniature computer disks. A common misconception is that the recordings on these disks are digital, as on the larger floppies used in computers. In fact still video cameras produce and record a conventional analogue video signal. To use the images in a computer they had to be converted from analogue electronic to digital using a digitizing card.

Video stills became possible when solid state imaging devices known as Charge Coupled Devices, or CCDs, became available.

The charge-coupled device (CCD) is at the heart of any electronic camera. The CCD takes light and turns it into voltage. The bigger your CCD, the higher the resolution and the bigger the file.
The Kodak DCS 420 CCD is only about a quarter the size of the CCD of the Kodak DCS 460 .

CCD chips, in their infancy when the first Mavica was launched, developed rapidly for use in broadcast television cameras. Today, CCDs have completely ousted camera tubes from domestic, industrial and broadcast television cameras.

Although Mavica cameras were marketed in Japan and America, Sony never produced a 625-line PAL camera for the European market. They left that honour to Canon, who introduced the 625-line PAL Ion RC-251 still video camera through high street stores. With a digitizing card in the Mac, digital images can be obtained from these cameras.


The phrases 'Electronic Imaging' and 'Digital Imaging' may seem interchangeable but do they mean the same thing?

The truth is that all digital imaging is electronic but not all electronic imaging is digital. And, if we are to be pedantic, there is no such thing as a digital camera because CCDs are analogue. Confused? You won't be.

Most television cameras, and video still cameras such as the Sony Mavica and Canon Ion, are electronic but not digital. Digitization if any, takes place outside the camera. Those which we call 'digital' carry out the analogue-to-digital conversion inside the camera. No longer are special Nu-Bus cards required to digitize the image.

This report first appeared as "MacUser" magazine 9 June 1995.
This document is Copyright © 1996 John Henshall. All rights reserved.
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