Strange interference, looks like a Bayer filter!?

twinquartz · Expire: 2013-10-29

Here is the setup: Canon EOS 600D, lens Zuiko 50mm 1:3.5. On my desk I have an Intel SSD box which I use for focusing experiments because it has got a lot of high DPI print on all sides.

Tonight, when having the Intel box about 71 cm from the camera's "film plane" and f/5.6, I got some very strange interference when I was focusing on a grey dotted area. The interference is fully visible when I open the RAW file in Camera Raw (100%).
Does anybody have a good explanation for this strange behaviour?

philslizzy · Joined: 07 Aug 2012 Posts: 4748 Location: Cheshire, England

Its the halftone screen dots of the printing. They are usually arranged in patterns. If the dots are about the same size as a pixel there will be 'moire pattern' interference. read this*, it does tend to concentrate on straight lines but dot patterns have this effect. I'm sure someone will be along to explain better than I.

*http://en.wikipedia.org/wiki/Moir%C3%A9_pattern

David · Expire: 2013-01-25

Phil' answer is about as technical as you'll get. Here are ways to avoid this:

- Buy a Sigma camera with a Foveon sensor
- Buy an older non-Bayer DSLR
- Buy an K-3 which has no AA filter but vibrates the sensor to simulate AA filtration.
- Change your angle and see if that helps. It may not.

LucisPictor · Expire: 2013-12-03

Or get a Fuji X cam. Wink

skida · Posted: Wed Apr 23, 2014 10:45 pm Post subject:

Don't take photos of boxes which are printed. Wink