Possible solution to moire problems :))

A

ajbazalo

Member
Hi guys:

I'm new with Canon 60D and it's horrible to see moire effects in buildings and clothes. The solution is not to defocus or to set the camera out of sharpness, but moving the aperture to f22, so the lens can obtain more precise information about shapes and lines. If you set the camera in another f value under or above 22 you will have moire.

You can see a sample in this link: http://vimeo.com/26437296

Regards from Barcelona!
 
Setting the camera to f/22 introduces diffraction to the image. It's an overall blurring of the image. It does, inherently, help cut down moire, because it cuts down all detail. It makes the image softer, throws things out of focus, and therefore cuts out the aliasing that leads to moire.

Try it yourself in stills. Shoot at f/5.6 with a high shutter speed, and at f/22 with a lower shutter speed, and you'll likely see there's a big difference in resolved sharpness.

Stopping down to f/22 is like throwing the camera slightly out of focus.

It is, therefore, a valid technique for combating moire, by lowering the lens' sharpness down to a level where the sensor can cope with it better.
 
Barry Pretty much said it all.

You can reduce the moire by by doing this but it has other negative impacts such as introducing softness (which is what eliminates the moire) as well as Chromatic aberations.
 
Heh. This reminds me of golf. Any "fix" has nothing to do with the REAL problem....it just gets you into a position that addresses the REAL problem. :) It's always better to know that the REAL problem is and the REAL fix. :) Thanks Barry!
 
Another solution is to use cheap lenses which can be had for as little as $20 used. I know someone who swears by brands like Kiron, Soligor etc. The lenses are well made, mainly metal construction, but too soft for stills photography but seem to work well for video.
 
Well another solution is to lock down your shot if possible. Yes, you will still have the same amount of moire but it won't be dancing all around and will be much less noticeable.
 
Yep, excellent point. Aliasing calls attention to itself in motion, because it moves opposite to the camera direction. Locking down your shot will make a lot of the aliasing effect less noticeable. Won't eliminate it, but it won't call attention to itself quite like a moving shot would.
 
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