How to get rid of the "moire" effect in digital camera photos?

Question

My first question was accidentally deleted so I need to ask again. How do you get rid of the "moire" effect when taking photos with a digital camera. I am using a Nikon D40 and took some pictures of an earthquake damaged building and it has considerable moire effect. I have Adobe CS2 - what is the procedure to get rid of it in the existing picture and how do I set the camera to avoid when taking similar photos?

Answer 1

In CS2:

- Duplicate the background layer;

- On this duplicate layer apply the High-pass filter at radius (3.8)

- Apply a Gaussian blur to this at radius (0.9)

- Invert the layer;

- Set blending to Linear Light;

- Set opacity at 50%;

- Mask to show only where you want to take out the Moire.

Moire is caused by distance/focus/aperture combinations.  In real terms it has to do with the limits of what your sensor can resolve.  There's a ton of technical stuff here:

http://en.wikipedia.org/wiki/Moir%C3%A9_...

Keep checking your LCD or move back a bit and/or select a smaller/larger aperture to get rid of it if you see it.  

Answer 2

You only get a 'moire' effect when you copy an image from a printed page. The original dots of the image do note line up with the dots on your screen and then you get a moire effect.

Do you mean 'artifacts'? Coloured dots in the darker area of your image? These are caused when you use a very high ISO setting on your camera. These can also be caused in digital images when you repeatedly save the same image as JPEG's.

Nick