After reading a number of the notes on digital photography I felt I must weigh in on the issue.
First of all no digital camera on the market today, under $6000, will yield a photograph with the information in film of comparable speed. If one wishes the
optimum digital image the best way is to use existing photographic equipment and get a good film scanner, for under$1000, to convert the negative or positive to digital. The result will be a very high resolution, ~2700 pixels per inch, digital, non-interpolated image. Also one has the original slide or negative as a permanent record. Images of this resolution allow significant cropping and other image manipulations. Using existing equipment, usually an SLR with a macro lens, one can control depth of field, lighting and composition better than any point-and-shoot digital camera.
If one needs a digital camera for publication quality images then the best choice is a through the lens camera, SLR type, with focus and aperture control. Both Canon and Nikon make professional quality digital cameras with interchangeable lens and the supporting hardware to go with them. Yes they are expensive. The Canon D30 body alone is $3000. But these cameras take the high quality lens most schools already have.
Some things to keep in mind:
For close-up or macro photography autofocus is not recommended. One really has no idea where the camera is focusing and the LCD display on a digital camera is not sharp enough to check focus under these circumstances.
Aperture and lighting control are critical for high quality close-up photography.
For field photography one can get excellent pictures using a modern point-and shoot camera for significantly less money than a digital camera.
If you plan on publishing the image, stay away from JPEG until you are storing the final image. JPEG is lossy compression and discards information in the image. This information is reconstructed to work with the file. Any manipulation and subsequent storage of the image result is discarding different information. As a result one might get into compression artifacts. For this reason all presses that I am aware of that work with digital files insist on TIFF files.
Having said all this I am personally mostly digital. The reason is because of the control over the final image which is available. The "digital darkroom" is a great advance to working in a chemical darkroom and this control over the final image is real deciding factor.
When buying equipment one should remember that the rules of photography haven't changed, only the way the image is recorded and manipulated.
Tom Whiteley
tomw@rochester.rr.com