"Moiré problem " Wed 15-May-13 01:39 PM by Kropotkin
I've taken some shots of a guy in a suit.
OK. So here it looks ok. On the camera LCD it looks terrible; both sides of the suit have a massive moiré effect. In Capture NX it looks fine though. Then I've put it into Photoshop Elements to do some final edits and the moiré effect is back. This is what it looks like in Photoshop when I've done Fit to Window. (This is a screen capture).
It took me a while to understand what is going on. Basically viewed at 100% and whatever size NX puts it in it is fine. The moiré effect occurs when I choose Fit To Window in Photoshop. So it is the result of scrunching it up. Same explanation for what is happening in the camera LCD.
But my concern is that the image has some kind of potential moiré effect. E.g. if you take this image which is attached and do Fit to Window in Elements you see the effect (only not so strongly as in the original).
If there was moire present in the image from the camera, would it not show up at 1:1 magnification?
From your description I understand the effect is being created when you're viewing at smaller magnification that 1:1, which makes sense to me. I'd say it's the "scrunching" which causes you to see it, but it may not actually be there in the original image.
If you downsample the image (save it smaller than original) so that it fits fully on your screen at 1:1 magnification, is the effect there as well?
That's exactly right. There is no moire in the image - it's created through resizing for display. We've seen the same thing come up with downsizing images - even a print that had no moire in the NEF.
The cause is a related to interpolation during resizing. You can resize and use a different interpolation routine. In Photoshop/Lightroom there are something like 6 different options - just experiment with the other choices.
In Capture try downsizing to an alternative size and quality. Reduce quality if needed.
>Moiré problem on screen is due to miss match of image >resolution and screen resolution which causes the aliasing >effect to appear. > >And if moiré is not visible at 100% magnification there is not >any moiré problem on the image anyway. > ^^^^This. The moire is an artifact of the re-scaling to a size that is not a power of 2 of the 100% image. You will likely find that the moire is not apparent at 50% or 25% or 12.5% but will show up at 33% or 67% which are not 1/n scaling where n is a power of 2.
As has already been mentioned, the problem is not the image but rather a function of mismatch between image and screen resolution which you cannot match as there is no way of knowing the specs of the viewer's monitor or how much of their screen the image will occupy.
If the image is to be printed there will be no problem. If the image is to be posted to the web or displayed on a monitor you can take one or both of two actions.
1. Increase the size and hence resolution of the image. The more pixels in the image the less moire patterns will be visible.