A number of users on rec.photo.digital have reported small white spots appearing on their images intermittently. This was first reported to me by Charles Hemstreet in mid-November, 1997.
At the time, I hadn't noticed any spots on my pictures but when I went back and looked more closely at some of them, I saw the spots too. I guess I had just never noticed. Now that I know what to look for, I see them all too frequently.
The spots appear to be randomly-placed, and only on flash photos. The spots resemble dried water spots left on drinking glasses by a dishwasher. Charles did extensive research and concluded that the spots seem to be dust reflected by the flash. Stirring up dust before taking a photo increased the chance of seeing spots on the image.
According to a posting in rec.photo.digital, dust spots as the cause of the problem has been confirmed by a technician at Olympus in Europe, but I'm not sure whether this was official or unofficial. I attempted to get information from someone described to me as "head of tech services" at Olympus America but my email was not answered. However, Steve Maller talked to an Olympus rep at MacWorld Expo who confirmed that the problem was dust very close to the lens being illuminated by the flash.
The problem is aggravated by lightening (increasing brightness) or gamma-correcting an image. Lightening an image may reveal spots that were previously too dark to be seen.
Charles has a page describing his results at: http://www.pacifier.com/~marmot/d320l/ .
This problem apparently isn't unique to the D-320L or even Olympus cameras. It has also been reported on the D-220L and D-300L and also on Kodak and Canon digital cameras. What makes this problem so frustrating is it can strike at any time and there's nothing that can really be done to prevent or reduce it. It just happens sometimes.
There seems to be nothing that can be done to stop or reduce the problem with the current line of cameras. It is not clear whether Olympus has officially acknowledged the problem and is planning on doing anything about it in the short or long term (assuming anything can be done).
One theory is that it is related to the small CCD size and the close depth of field of the optics in digital cameras relative to a film camera.
Ryan Weal sent me email: he found that these spots are not restricted to digital cameras; he found similar spots on photos taken with a cheap ($15-20) 35mm film camera.
Shown below are key sections taken from a larger image illustrating the spots problem. The images on the left and right in each row are the same area of the image with and without gamma correction. The full-size images are also available with and without gamma correction.
Allyn's note: This site is no longer actively maintained. It is retained online in hopes that most of the information is still useful, but links to other sites may be broken.
Send some email: Allyn Fratkin <firstname.lastname@example.org>
Want to know more about me? Visit my web site.
The text and images shown on these pages are Copyright © 1997-2000 Allyn Fratkin and Teri Fratkin. References and links to other sites are for informational purposes only and do not constitute an endorsement of those sites.