I remember well (although apparently not well enough) reading an article by Galen Rowell (yes, the other Galen) about how he was able to create a diffraction fringe around a fellow climber and his ice axe. It’s a fantastic photograph, his friend standing majestically off in the distance atop a rock jutting out into space, and this line of pure light encircling him. (I don’t have the rights to this image, but a quick web search should get it for you.) And I thought to myself… What a wonderful natural phenomenon to capture. And it’s tickled away in the back of my mind over the years, since I read his article. And over the years, apparently I’d forgotten one of the key factors that is apparently needed to recreate this effect. And no, I don’t mean that I’ve forgotten to carry a mountain climber and an ice axe with me wherever I go. What I’d forgotten is that you need exceptionally clear air in order to allow the light to diffract and bend around the subject in a coherent (visible) way, and you are ideally some distance below your subject.
Yesterday at sunset I did however manage to falsely recreate this effect with a sheep. It turns out all I’ve ever needed was a subject that was fuzzy (or wooly) enough, so that the fuzz could get lit up by the sun and I could pretend that I was diffracting the light around the subject (although this is also a form of diffraction, except that light is having to pass through something solid, instead of simply curving through air).
So to break down faux fringing for you. Get yourself a fuzzy subject. A sheep is ideal, although cows can work keep in mind that fuzzier is better… maybe one of those scottish highland cows… Next, get your subject silhouetted against the sky as the sun is going down. Place yourself a proper distance from your subject so that its body will just block out the entire sun. This will likely be forty to sixty feet away, although it will depend on the size of the sheep. Adjust your aperture and shutter speed so that your subject is a silhouetted shape and so that the sky is not blown out. In the case of the above photograph, I had the aperture set to f/9 and the shutter speed was 1/2500 (all of this at ISO 320). You will get similar effects, even at apertures that are stopped down farther, as long as you adjust your shutter speed or ISO accordingly.
Here is a cropped down version, so that you can see the wool more closely. Observe that this is not a true “diffraction fringe.” Fuzz was required.