Bela

Hi:
My hobby is genealogy and I use the built-in camera on my Nokia N8 smartphone to quickly copy documents when doing research. The 12 MP digital camera has Carl Zeiss optics, a focal length of 5.9 mm and an aperture of f2.8. I have also used a Canon PowerShot G11 10MP digital camera.
I have used both cameras at an archive, where the USB port was de-activated on the microfilm scanners, and tried to shoot still photos of the images displayed on the microfilm reader display. Photos with either camera demonstrated moire patterns, which were quite variable from image to image. Is there anything I can do to minimize / eliminate the moire patterns if I find myself in the same situation in the future?
Will I have the same issue when using traditional microfilm readers, if I try to take a photo of the displayed image on the base of the reader?

Many thanks.

snowbear

Try moving the camera closer to, or farther from the subject. The issue is the resolution of the sensor(s) or the absence of anti-moire filters.

source: http://dpbestflow.org/camera/sensor

les_stockton Loc: Eastern Oklahoma

I checked http://www.oberonplace.com/dtp/moire/index.htm.
It suggests using gausian blur to remove it. You might also check on youtube to see if moire patterns are mentioned, because a lot of photographers put videos there on various subjects.

http://www.youtube.com/watch?v=uFmJjvWYQ7M is a good one.

Ann B Loc: Northeast Indiana

I don't know for sure about photographing the films, but at the publishing company I worked at when I scanned an image from something that was printed (i.e. from an old newspaper clipping or a yearbook) I found that if I put it in the scanner at a slight angle the moire pattern was diminished significantly when I straightened it. Might be worth a try to see what happens with the film.

ephraim Imperio

"When the moon hits your eyes with a big pizza pie, thats a moire`" Joe Kronin.

Just kidding! Here is a link from the Mansurovs on how to avoid moire.

http://mansurovs.com/how-to-avoid-moire?utm_source=rss&utm_medium=rss&utm_campaign=how-to-avoid-moire

RMM Loc: Suburban New York

Similarly, I did some work for a company selling stamp collections. They scanned the stamps at an angle, then cropped and realigned. Not sure if this will work on a microfilm screen, though.

Les Stockton's suggestion may also work. I've sometimes created a duplicate layer, used a Gaussian blur to remove the moiré, then sharpened again. You may try lowering the opacity on the second layer if you lose too much detail before flattening and resaving the image.