Old film guy wants to know: is there is any sure-fire way, in the field and on the fly, to eliminate moire from certain songbirds wingbars/tail? From what I gather, the best chance is to back up and stop down. Any certainties out there? (I'll settle for 95%).
I'm not sure what has prompted your question - are you seeing moire in some of your images?
I've been shooting digital now for 10 years and have only seen moire in a single subject, a Mourning Dove shot with a Nikon D70. See my blog for the image and particulars.
Are you seeing moire patterns from your D800E? It is more likely to produce the problem since it does not have th AA filter, but I have not seen this be an issue for any subjects.
Looked at your photo, Richard. Think that I should know moire before I speak. But it's this sort of stair step appearance that's driving me bonkers.. I see it fairly commonly. If it were just on mine, I'd blame it on motion or a blast of flash. In retrospect, it does seem to happen on mine most obviously in well lit scenes. Is it overexposure, that is, tiny blown whites that are unresolvable against darker? Sure would like to get rid of it, forever.
And thanks, Keith. I will one day not allow my shutter speed to fall below 1/500th sec and keep my iso over 400. I'm stubbornly knuckleheaded, sometimes. (I won't let it fall below 1/125, now. It will probably take a blurry U.S. mangrove warbler shot to fully convert me. Or as Thomas Payne put it: "time makes more converts than reason". Thanks, fellas.
Another extreme example. See it fairly often, to a lesser degree, on otherwise quality NPN photos. Have a "gut feeling" it will subside with shade, but I'd like to be sure. And if I knew what it was, it would truly help me and others avoid it.
I think this really is another example of moire; at least in terms of the spacial frequency of the data (alternating dark and light parallel lines) that don't quite line up with the rectilinear layout of the individual photo sites on the camera sensor. You are trying to make a clean sharp diagonal line when your "pen" can only move north-south and east-west - you end up with tiny steps instead of a smooth line.
The effect will be more pronounced as the contrast increases (either direct light or too much contrast increase in post processing). Sharpening the image does exactly the same thing as the various sharpening techniques rely on increasing the contrast between adjacent pixels.
You can avoid/minimize this by:
- using a lens with less resolution
- missing focus on the critical areas
- being careful how to apply sharpening in post processing (apply it selectively, and use less on these areas)
- applying a small amount of blur
- limiting the amount of crop/magnification to reasonable degree - you're working with a camera and not a microscope after all.
Todd,
I think the problem you are seeing is mainly due to the raw converter and the settings in the raw converter. Try a different raw converter, or a different algorithm within the raw converters (most raw converters do not give that choice), and/or back off on the sharpening settings in the raw converter.
Richard resolved this case with an easy to understand explanation. Thanks. (Only cropped this tightly for this question. I notice it full frame on the RAW file of the camera's viewfinder).
Discussion
7 repliesI've been shooting digital now for 10 years and have only seen moire in a single subject, a Mourning Dove shot with a Nikon D70. See my blog for the image and particulars.
And thanks, Keith. I will one day not allow my shutter speed to fall below 1/500th sec and keep my iso over 400. I'm stubbornly knuckleheaded, sometimes. (I won't let it fall below 1/125, now. It will probably take a blurry U.S. mangrove warbler shot to fully convert me. Or as Thomas Payne put it: "time makes more converts than reason". Thanks, fellas.
The effect will be more pronounced as the contrast increases (either direct light or too much contrast increase in post processing). Sharpening the image does exactly the same thing as the various sharpening techniques rely on increasing the contrast between adjacent pixels.
You can avoid/minimize this by:
- using a lens with less resolution
- missing focus on the critical areas
- being careful how to apply sharpening in post processing (apply it selectively, and use less on these areas)
- applying a small amount of blur
- limiting the amount of crop/magnification to reasonable degree - you're working with a camera and not a microscope after all.
I think the problem you are seeing is mainly due to the raw converter and the settings in the raw converter. Try a different raw converter, or a different algorithm within the raw converters (most raw converters do not give that choice), and/or back off on the sharpening settings in the raw converter.
Roger