I'm shopping for my first digital camera. Presently, I'm interested in two. The Nikon 900s and the Olympus 400z. They seem to be very close in features and performance. I don't understand when comparing your test images the Nikon in all cases had a larger file. Since they have identical resolution 1280 x 960 shouldn't they produce similar file sizes in their high res. mode? Some of the images i've downloaded from the Nikon web page to show the Nikon 900s to be better at capturing images. Their sizes are about 525k. Still much larger than what you have for the Olympus 400z. Correct me if I'm wrong but I equate file size with resolution and quality. Why are the 400z images 25-35% smaller?

-- Phil Patrick (patricks-hv@worldnet.att.net), January 24, 1999

Answers

This question comes up a lot, we really need a FAQ to deal with it. The differences have to do with tradeoffs mfrs make on the image compression. Yes, in general, more kilobytes will mean more data/fewer artifacts, but doesn't necessarily have anything to do with resolution, which is more strongly related to the sensor size. All the cameras use JPEG to throw away "irrelevant" information in the images and compress them to a smaller file size. Different mfrs use different amounts of compression. At the highest quality/lowest compression ratio, you'll probably find the Nikon and Oly 400z pretty close in image quality. Possibly Oly went with a bit more compression, since they also offer a completely *uncompressed* mode, in which the images remain at their roughly 3.5-4 megabyte original size on the memory card.

-- Dave Etchells (web@imaging-resource.com), January 24, 1999.