## Breaking Down Lens Flares

What gives Knoll Light Factory its power is the research John Knoll did into how lens flares work. He identified 19 camera lens “primitives” which are the different artefacts that occur when you photograph bright objects.

Every lens flare is formed from some combination of these primitives. The resulting flare depends on the specifics of the lens, how bright the object being photographed is, where it’s positioned, the medium between the lens and subject, and many other factors. Information on how each of the 19 primitives is formed in real life can be found in the plugin’s user manual.

Knoll Light Factory ships with more than 100 presets based on real world lenses and typical cinematic effects. All these presets are built from the same primitives and can be modified endlessly to suit your needs.

In the following two examples, you will see how different combinations of primitives can be employed in different ways.

## How to Add a Lens Flare to a Backlit Portrait

Adding a lens flare to a backlit image is one of the most common uses for Knoll Light Factory. It’s a popular effect in commercial and portrait photography.

Above is an image of a model named Kat that I photographed in the woods near my home in Ireland. The sun was largely hidden by the trees in the background so, although it’s backlit, there was no noticeable lens flare. I’m going to add one to this image. To follow along, open any backlit image you’ve made.

### Step One: Open the Image in Knoll Light Factory

Applying a lighting effect from Knoll Light Factory should be one of the final steps in your workflow. The effect is rendered by the plugin so cannot be modified after it is applied. When you have processed an image to the point where you are ready to apply the light flare, create a new layer on top and merge all visible to it.

Select this layer then select Red Giant Software > Knoll Light Factory from the Filters menu item. This loads up the plugin.

### Step Two: Select a Preset

Knoll Light Factory ships with more than 100 presets. There is almost always one that will work as a base for the effect you want to apply to your image. The presets can be selected and previewed by double-clicking on any icon from the Presets menu.

I made this photo with a Canon 85mm f/1.8 lens, so the 85mm preset is a good place to start.

### Step Three: Tweak the Lens Flare

When you first apply the lens flare it will appear in the centre of your image. It’s highly unlikely this is where you want it. To position it in your image click where you want to place it in the Preview panel. For me, that is the middle of the bright sky highlight.

I’m going for a sunset look here, so I want a more orange than red flare. This means the first modification I’m going to make is to the Color. To change the colour of your flare, double-click on the colour swatch and use the colour picker to find a colour that works with your image.

If you want to change the intensity or size of the flare, use the Brightness and Scale sliders respectively. I increased the scale of the flare slightly in my image.

### Step Four: Modify the Primitives

Each flare is made up of a number of primitives. In the case of the 85mm preset, they are a GlowBall, a PolySpread, a StarFilter, a SpikeBall, a FadedRing, an ElipticalCaustic, and a StarCaustic. Each of these contributes to the final effect. The easiest way to see what each one does is to turn it off and on using the check box next to it.

With this preset, there is only one change I want to make. The FadedRing is obscuring Kat’s face and detracting from the overall image. By turning it off, the lens flare effect may be marginally less photorealistic but the image is a lot more pleasing.

You can add, remove, or modify as many primitives as you like until you get the effect you’re looking for. Once you’re done, click OK to render out the results. You can now export the final image.

## Add a Twinkle to a Ring

While adding a lens flare emulates a real world situation, there are plenty of times you’ll want to add surreal lighting effects to your images. Extreme light effects are one of the hallmarks of the hyperreal style of commercial photography but it has uses elsewhere. For example, a wedding photographer could use Knoll Light Factory to add a twinkle to the wedding rings.

In this example I’ll to use the same image as before and add a sparkle to Kat’s ring. You can use any photo of someone wearing a ring for this.

### Step One: Open the Image in Knoll Light Factory

As before, get your image to a near-final state and then merge all your visible layers to a new top layer. Select it and open Knoll Light Factory.

### Step Two: Select a Preset

After playing around with a few different presets, I found Two Way Rays to be the best for adding a simple twinkle effect. Select it from the preset menu to continue.

### Step Three: Tweak the Lens Flare

Position the effect over the model’s ring. I’m going for quite a hyperreal effect so I increased the brightness and scale of the flare. I also changed the colour to a grey (to emulate silver).

### Step Four: Modify the Primitives

While I like the effect so far, I think it could be more intense. The Two Way Rays preset only includes a GlowBall and two StarFilters. To increase the intensity I added another primitive; this time a Poly Spike Ball.

To add a primitive, select the one you want from the drop-down menu and click Add Element. You can then tweak it, or any of the other primitives, using the options provided. The defaults for the Poly Spike Ball give the effect I want for this example so no need to modify it further.

Once you’ve tweaked the twinkle to your satisfaction, click OK to render everything out and export your final image.

## Conclusion

Red Giant’s Knoll Light Factory is an incredibly powerful Photoshop plugin developed by one of the program’s original creators. If you’re looking to add lighting effects to your images it’s the best way to do it. You can quickly and easily add effects like a lens flare to a backlit portrait or a twinkle to a ring as I’ve shown in this tutorial.

There are, however, no limits to what you can do. The effects were originally developed to create Star Trek’s photon torpedoes so, if you want, you can add them or anything else to your image.