The mysterious green blob that sometimes shows up in photos, especially older photos, is a phenomenon known as “lens flare.” Lens flare occurs when non-image light enters the camera lens and reflects off the camera’s lens elements, creating shapes, circles, and colored blobs in the resulting photograph.
The green color of the blob comes from the optical coatings used inside camera lenses. Most quality lenses have special anti-reflective coatings to improve image quality. These coatings are precisely designed to reduce internal reflections and flare, but they are not 100% effective. The coatings used often give reflected light a greenish hue, and that gets picked up in the photo as a green flare.
Lens flare is generally considered an unwanted artifact in photography. The blobs, shapes and haze reduce image contrast and quality. However, some photographers intentionally use lens flare creatively, often for a retro, dreamy or sci-fi look. J.J. Abrams famously added lens flare effects to Star Trek and other films he directed.
What Causes Lens Flare?
Lens flare occurs when stray light enters the lens and bounces around between the glass elements before hitting the camera’s digital sensor or film. This typically happens when a bright light source, like the sun or a lamp, is inside or close to the camera’s field of view.
Light rays reflect and scatter off the rounded edges and interior surfaces of the lens glass. These reflected rays land on the camera sensor in oval shapes, rings, starbursts and colored blobs. The location and look of the flare is determined by the path the light takes as it reflects around inside the lens barrel.
Green lens flare is common because most quality lenses use green-tinted optical coatings to reduce internal reflections. As stray light bounces around, some of it reflects off these greenish coated surfaces, picking up a green color cast.
Types of Lens Flare
There are many types and shapes of lens flare:
– Blobs – Random colored blobs, usually circular in shape. Most often green from lens coatings.
– Rays – Streaks or lines radiating outward from a bright light source.
– Polygonal shapes – Often hexagons or octagons from light reflecting through round aperture blades.
– Rings – Concentric rings around a light source.
– Veiling flare – Overall haze reducing contrast.
– Starbursts – Multi-pointed stars from a bright light source.
– Ghosts – Out of focus replicas of a bright object like the sun.
So in summary, the green blob flare is just one of the many possible lens flare artifacts. The green color comes specifically from internal reflections off the anti-reflective optical coatings used in most lenses.
What Factors Cause More Lens Flare?
Certain cameras, lenses, settings and shooting conditions make lens flare more likely to occur:
– Wide angle lenses – Their wider field of view makes it more likely to catch a bright light source.
– Lenses with more elements – More glass surfaces for internal reflections.
– Lenses without lens hoods – Hoods block stray peripheral light.
– Smaller aperture (higher f-stop number) – Creates starburst effects around bright points.
– Shooting into the sun or bright light – Main cause of flare.
– Backlighting and strong side lighting – Puts bright lights in frame or near edge.
– Reflective surfaces – Bodies of water, windows, metal, etc.
– Old, damaged or lower quality lenses – Degraded coatings allow more internal reflections.
So lens flare tends to show up more in wide scenic shots, night photography, shoots into the sun, and images with reflective surfaces. Using a lens hood helps mitigate flare substantially by blocking stray light from striking the front element.
How to Prevent Lens Flare
Here are some tips minimize lens flare when shooting:
– Use a lens hood – Blocks stray peripheral light from entering front element.
– Avoid aiming at light sources – Keep sun, lamps, windows out of frame.
– Shoot at low f-stops like f/2.8 or f/4 – Creates shallower depth of field and less starburst patterns.
– Use prime lenses – Generally have fewer lens elements than zooms.
– Clean lens elements – Smudges contribute to flare.
– Add a filter – Can help protect front element and reduce flare.
– Shade the lens – Use hand, hat or other method to block light.
– Change angles and compositions – Move so bright lights are not near frame.
During post-processing, lens flare can sometimes be reduced or removed using editing software tools like Photoshop, Lightroom and plugins.
However, when shooting, the best way to avoid heavy lens flare is to be aware of bright light sources in or near the frame and compose shots to exclude or minimize them. Using a lens hood also goes a long way in blocking stray light from causing flare issues.
When is Lens Flare Beneficial?
While lens flare is traditionally seen as an unwanted artifact, some photographers intentionally use it for creative effect.
Small amounts of flare can add atmosphere and a dreamy look to images. Anamorphic lens flare creates oval bokeh and streaks that can look cool, especially for urban night shots.
For a retro feel, lens flare creates effects reminiscent of older lenses and film days. The soft flare glow evokes a warm, nostalgic vibe.
Science fiction movies like Star Trek, Star Wars and others use lens flare to give a futuristic look and atmosphere. Many movies add lens flare effects digitally in post-production.
So whether lens flare adds or detracts from an image depends on the type of photo and creative goals. It’s generally avoided in commercial photography that requires clean, crisp images. But flare can be embraced for artistic effect in more stylized shoots.
Examples of Good and Bad Lens Flare
Here are some examples showing lens flare used both positively and negatively:
| Good Lens Flare Example | Bad Lens Flare Example |
|---|---|
|
|
| This night cityscape uses lens flare creatively to add atmosphere. The streaks direct the eye and add interest. | Harsh sunstar flare reduces contrast in this landscape, overwhelming the image. A lens hood could have prevented this. |
As you can see, lens flare can be used to artistic effect in some situations while being distracting and unwanted in others. Learning to control flare takes practice and experience.
Frequently Asked Questions
Here are answers to some common questions about green lens flare blobs:
Why is lens flare usually green?
The green color comes from lens coatings. Most quality lenses have specialized anti-reflective green coatings to reduce flare. Light bouncing off these coatings produces the green hue.
What is ghosting and how is it different from flare?
Ghosting creates clear copies or “ghosts” of bright objects like the sun in photos. It comes from strong reflections between elements. Ghosting is a type of lens flare.
Can lens flare be fixed in post processing?
Sometimes but not always. Software tools like Photoshop can reduce or remove lens flare artifacts using cloning, healing and masking techniques. But results vary based on the image. Preventing flare when shooting is better.
Should I intentionally add lens flare in post processing?
Digitally added flare can look cheesy if overdone. Subtle real flare from shooting often looks better. But for sci-fi shots or anamorphic looks, added lens flare can help achieve the desired stylistic effect.
Does aperture size affect lens flare?
Yes, narrower apertures (higher f-stop numbers) can exacerbate flare, especially starburst patterns around bright lights. Using a wide aperture minimizes this.
Conclusion
In summary, the mysterious green blobs that show up in some photos come from a phenomenon known as lens flare. Flare occurs when stray light bounces around inside the camera lens off the multiple optical elements and anti-reflective green coatings.
While traditionally considered an unwanted artifact, lens flare can be used creatively for stylistic and atmospheric effect. Photographers intentionally add flare for dreamy, retro and sci-fi looks.
To control lens flare, use quality lenses with optical coatings, lens hoods, avoid aiming at light sources, and watch for flare when composing and shooting. Post-processing can also sometimes reduce unwanted flare artifacts.
So next time you spot some green blobs in your images, you’ll know what causes them and techniques to minimize or utilize them artistically. Lens flare can be both friend and foe to photographers, depending on the situation. Mastering this optical phenomenon will give you greater creative control.
