Our earliest encounters with lens flare are predominantly negative. As newcomers to the wonderful art of photography, we are often told that we should avoid lens flare at all costs. We become engrained with the thought that flare is not good.
Like many things in photography, lens flare has a dual personality. Yes, there are (many) times where we might wish to avoid it, where it could entirely ruin a picture. However, there are also plenty of times when we can and should embrace it. Not for nothing do the likes of Adobe have a lens flare filter in Photoshop. Big Hollywood productions will often use lens flare as a creative tool.
Today we are going to look at lens flare, how to control it and when you might want to embrace it.
What Is Lens Flare?
Our lenses are made up of multiple different glass elements. There are several reasons for that, getting the right focal length, minimizing distortions, improving contrast, and reducing lens flare. The latter, they are pretty good at, but not perfect. No lens design can eliminate lens flare 100%, it’s down to us to recognize and control it. But what is it?
We, I am sure you have seen the effect, streaks, or circular ghosts of light in inappropriate places in your images. It can be caused by a number of different factors. Chief amongst those is light hitting those internal elements of your lens at oblique angles. This light can then reflect back off of the internal surfaces of those elements and find its way to the sensor surface.
The sensor itself can also cause a lens flare. Most sensors have a protective glass filter covering them. If there is a direct light source hits that sensor at the right angle, it can, again reflect off of the internal lens surfaces and back to the sensor.
Any light source within the lens’s field of view capable of causing lens flare. The more perpendicular that light source is to the lens or sensor, the greater the likelihood of lens flare.
Now that we now what lens flare is, how can we control it?
Controlling Lens Flare
The first thing we should note about lens flare is that it is not one of those things that can be “fixed in post”. At least not easily. The random nature and form of lens flare can make it very difficult to remove using clone or heal tools. As well as causing the obvious blemishes on our images, lens flare generally leads to a reduction in contrast. Let’s look at what we can do to reduce the problem.
- Clean your lens. The more fingerprints or dust you have on your front and rear elements, the prone that lens will be to flare. A common mistake is to clean the front element but not touch the rear. You should make sure both are clean. Use a proper microfibre lens cloth and lens cleaning fluid, or something like a lens pen to keep those surfaces spotless.
- Use a lens hood. The wider the lens, the more prone it will be to lens flare. This is simply because the wider field of view increases the chance of the light source being in the image. A lens hood will greatly reduce the chances of lens flare when the light source is in the periphery of the image. Make sure that you use the right hood for the lens. An incorrect hood may not reduce flare and may increase vignetting in some cases.
- Physically shield the light. You can greatly reduce the chances of lens flare by using an object in the frame to prevent the direct light falling on the lens. This could be something such as a tree, or building. Anything opaque will work so long as it is placed between your camera and the light.
- Beware of filters. Adding external filters to a lens can increase your chances of getting internal reflections and hence lens flare. The more filters you stack the greater that chance becomes. The most problematic type is the square system filter. Because there is a gap between filter and lens there is a greater chance of light reflecting off of the surface of the filter, even if the light source is not directly in the scene.
- Block the light. If your lens hood is not cutting the mustard in reducing lens flare, look at using your hand, or better still a piece of opaque card to block the light. This is best suited when shooting on a tripod unless you are particularly ambidextrous.
One important thing to note is that lens flare can be very subtle. Often it is not easily seen on our camera’s small LCD screens. If you are shooting any scene directly towards a light source, it is best to assume there will be lens flare and to take measures to control it. However, there are times when you might want to embrace it.
Embracing Lens Flare
Lens flare can be a powerful way to convey emotion in photography. Think of the low golden light of a sunset and how the flare from the setting sun makes you feel about that image. It makes you want to be there, to feel the sun’s last ray of the day.
Equally, perhaps you are shooting a model. The lower contrast and ethereal look of the lens flare can make people's shots look emotive.
The key to embracing lens flare is to control where you want it. That means moving your, your subject, or both into a position where the flare looks good.
As an example when shooting a model, you can position their head so that the backlit sun is partially blocked, allowing some light to seep through. You will have to constantly readjust to get the flare correct, a few cm left or right and you could just end up with nasty-looking circular flare on the model’s face.
Aperture is a very important aspect of the way flare looks. A wide aperture will give a soft, halo-like flare to your image, a nice look for portraiture. The smaller the aperture becomes the more of a starburst effect you will get around your light sources. This can look attractive in landscape photography and especially in night cityscapes.
Controlling lens flare requires patience and practice but it has the ability to make your images look very attractive and striking if done well.
Lens flare is an issue that as yet has not been overcome by computers or lens design. I am sure in the near future, the advent of computational photography and a move away from conventional lens design will all but eliminate lens flare. That would be good in some respects but sad in others, creative use of lens flare can really make an image. Whilst you could add it in post-production, nothing beats the feeling of you and your camera battling the light to bring lens flare under control.