What Is Lens Flare, and Why Does It Make Photos Look Weird?

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5 years ago

Lens flare is an optical effect in which light is scattered inside the body of a camera lens and appears in a photo as an artifact or contrast-reducing haze. It’s usually undesirable, but sometimes, you might want to use it for artistic or stylistic purposes.

What Causes Lens Flare?

Modern lenses are incredibly complex works of engineering. They aren’t simply concave or convex, but composites that use multiple elements for much better optical performance. The curved piece of glass you played with back in science class could never focus light enough for you to take a decent selfie.

When you look at anything, you see the light reflecting back from it. When you take a photo, the lens on your camera focuses this reflected light onto the sensor (or film). However, the reflected light isn’t the only light that hits the lens; rays are coming at it from all directions.

Most of these non-image light rays don’t matter for one (or more) of the following reasons:

They’re directed toward the body of the lens.
They’re absorbed by the lens elements or anti-glare coating.
They’re eliminated by the design of the lens and never reach the camera sensor.

However, if light rays come from a particularly bright source, they can be reflected, refracted, or bounced around enough through the different lens elements to reach the sensor. Or, they can interfere with other reflected, refracted, or bounced light rays. Either way, they’ll then appear in your photo as a lens flare.

Lens flare appears in the following two ways:

As a visible flare: Or, as a weird, polygonal artifact around, or opposite from, the light source.
As a bright haze: This reduces the contrast of the entire image.

Lens flare most commonly appears when you’re shooting directly at a bright light source, like the sun, street or concert lights, or a studio flash. It can appear both when the light source is included in the image or when it’s just out of frame.

The lens you use has a big effect on the amount and look of any lens flare. Modern lenses are mostly designed to minimize it and also have anti-reflective coatings. More expensive, professional and prime lenses are less prone to flare than consumer market and zoom lenses.

How to Avoid Lens Flare

Lens flare isn’t something you can always totally eliminate. However, if you follow the tips below, you can do your best to avoid it or minimize its effects:

Don’t shoot directly into bright light: This is, by far, the most common cause of lens flare. Avoid light sources that are either in, or just out of, a shot.
Use a lens hood: This will prevent as many non-image light rays as possible from hitting the lens, so leave it on your camera. It won’t prevent any lights in an image from causing flares, but it will massively reduce any from outside the frame.
Use prime lenses: They have simpler optical designs than zooms, so they’re generally less prone to flare.
Clean your lenses: Light can also reflect off of any dust or dirt on the elements of your lens and cause worse flares.
Avoid filters: UV or neutral density filters (especially if they’re low-quality) can make flaring worse.
Shade your lens: Whether you use your hand, a tree, or anything else, shading the front of your lens will block any out-of-frame light sources.
Move: In most situations, you can significantly reduce or remove lens flare by simply moving around. Change your perspective or reframe the shot.

How to Use Lens Flare Artistically

Again, lens flare is generally something you want to avoid. However, it can be used artistically— just ask J.J. Abrams. Accidental or unintended lens flare usually detracts and distracts from an image. If you deliberately include it (or add it afterward in Photoshop), though, it can enhance a particular vibe you might trying to capture.

Abrams might have taken it a bit too far in his Star Trek movies, but it was never the result of a technical misstep.

If you want to play around with lens flare in your images, here are some things to keep in mind:

Shoot directly at lights: If you’re including lens flare, you most likely don’t want to be too subtle. Point your camera at the biggest light source in the room.
Shoot during the golden hours: The hour just after sunrise or before sunset are the easiest times to get good lens flare. The sun is low in the sky, so you can easily work it into your shots. The light will also create a nice golden glow in your image.
Enhance afterward: Like any dramatic effect, you’ll get the best results from lens flare if you tweak your images later in photo-editing software.
Stop down the aperture: If you use a narrower aperture (like f/11-f/16), point light sources will render as cool starbursts. This is one of the best ways to include lens flare.
Shoot a few shots without it: What looks good on the back of your camera might not look so good blown up on your computer. Be sure to shoot some safety shots without any lens flare.
Embrace mood: Lens flare gives your images a specific look. Depending on how you use it, it can create a soft, dreamy, other-worldly look, or a dramatic, high contrast look.
Still try to minimize it: Even if you’re actively trying to capture lens flare, you still want to follow most of the tips we covered above. Keep your lenses clean, don’t use filters, and move around.
Don’t overdo it: Like any photography technique, lens flare loses its impact if you overuse it. Going full-Abrams in every image isn’t a good idea.