Sure, anamorphic lens flares (and lens flares in general) can be overused. As can extremely shallow depth of field, vintage color grading, or any number of stylistic approaches that catch on, see a lot of use, and eventually get labeled as a gimmick. But they can also be used creatively and selectively to enhance the visual experience of a story.
True anamorphic lenses aren’t the easiest to attain or use, factoring in price and the ability to mount to your camera. So a handful of companies have started selling anamorphic streak / flare filters that simply screw on to the front of your lens.
However, if aesthetics (read: “professional appearance”) don’t matter much to you, there is a super cheap alternative to achieving a very similar result. Best part of all, there’s no glass involved in this do-it-yourself method, so no worries about degrading or softening the image.
At minimum, you’ll need a short section of fishing line. How you attach it to the front of the lens is up to you. Ideally, you’ll want some way to mount this so that it can be easily attached and removed. In my case I drilled two holes on opposite ends of a cheap step-up adapter and knotted the fishing line at both ends.
This is only one way to mount the filament, so get as fancy as you’d like. I chose this particular step-up filter because my Variable Neutral Density filter threads onto the opposite end.
(If you prefer a ready-made solution with a professional appearance, have a look at the CineMorph filter from Vid-Atlantic.)
Notice the line runs vertically for a horizontal flare. This can be adjusted to change the streak direction.
The filament thickness makes a difference so you’ll want to experiment. In my case, I went with a rather thick 30LB test line. It can be colored to vary the color of the streak, but I prefer to leave mine clear. For a more exaggerated effect, try multiple lines spaced parallel.
Here are some color-graded test images (with 2.35:1 crop):