We modern digital photographers are a bunch of goofballs who might one day wonder why we spent so much time and energy intentionally trying to screw-up a photo with flare. And I will number myself amongst those who chased after the flare! [grin]
Engineers have worked hard to create expensive lenses that are impervious to chromatic aberrations such as sun flare. Lens hoods with non-reflective interiors have been created specially for each individual lens. Tutorial after tutorial after tutorial has been written to help us avoid sun flare. Expensive anti-reflective lens filters are available to decrease flare.
But. I've got to tell you: Sun flare is IN right now. It's hip. It's current. It's hot! But. I've also got to tell you: the rest of the world is going to think you screwed up when you show them your awesomely flare-endowed picture. I was thrilled last year to find flare on my tri-pod-achieved family portrait for our Christmas card. But my own mother (Hi, Mom!) wanted to know why I hadn't photoshopped out that green spot -- that green spot that was sitting squarely on my handsome husband's face, nonetheless. And she wasn't the only one who wanted to know why I hadn't fixed that "problem". :-)
So, in the spirit of trendy-ness (because, I fully acknowledge flare is "in" now, but might again be a photographic faux pas tomorrow), I hereby offer up the following tips for catching the flare. And, by the way, I accumulated this list by working backwards from the abundant tutorials describing flare avoidance. ;-)
1. shoot directly into the sun.
2. wiggle/tilt your lens around until you can see the flare.
3. cheap lenses are more likely to catch the flare (because of lack of anti-reflective coating on lens) than expensive lenses.
4. do NOT use a lens hood.
5. zoom lenses are more likely to catch flare than prime lenses (because they have more lens elements).
6. smaller apertures are more likely to give you better defined flare and detailed sun rays.
7. cheap UV/polarizing/neutral density filters can increase flare by introducing additional surfaces from which light can reflect.
8. and one more (from Aunt Tea in the comments): it's easier to catch flare in the early morning and the early evening when the sun is lower to the horizon.
So here's one of my recent attempts to catch well-defined flare. I was using my zoom lens (24-105mm), hood off, wide open 24mm, shooting right into the sun, with apertures ranging from f/4 to f/16.
It's pretty clear that f/16 gave much better definition to the flare (you can see it all the way to the bottom of the frame) and the sun rays than f/4. If I'd had a cheap filter for this lens I would have popped it on for good measure.
Here's one more experiment. I had my 85mm lens (prime, no zoom), a cheap UV filter, no hood, and an f/16 aperture.
Try as I might, the 85mm just didn't deliver much in the way of spectacular flare.
So, what do you think? Like flare? Not like flare? Think it's a weird current trend? Either way, you can use my list to chase after it, or avoid it like the plague.