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Living with Photography: Filling In for Fill Light

By Norman Chan

The very basics of lighting and how to compensate for nasty shadows using Lightroom's Radial Filter tool.

When I reviewed Adobe's Lightroom 5 a month ago, I said that its best feature was Smart Previews, which effectively let me work off of one shared Lightroom Catalog saved to Dropbox. That was so very useful when it came to processing over a thousand photos taken at Comic-Con a week and a half ago. But while developing those photos, I became acclimated to another of Lightroom's tools that I had dismissed in the past: Radial Gradient Filters. In my testing of Lightroom, my use of Radial Filters was limited to creating artificial vignetting around the edges of photos, as when simulating Instagram filters. But the Radial Filter tool turned out to be one of my most-used tricks for developing Comic-Con photos. It helped compensate for the fact that I still haven't started to use flash lighting.

Let's examine the photo above, opened in Lightroom. If the photo looks muted and flat, your eyes aren't deceiving you. This is how most of my RAW photos look when they're first imported into Lightroom. I tend to shoot with exposure set 1/3rd or 2/3rd of a stop down, which produces darker photos but at a higher shutter speed (trading brightness for a potentially sharper image at my chosen ISO). Clarity, colors, and white levels are bumped up in the first development pass, which makes the photo pop a lot more. But even with the color information accessible in the RAW photo, there are details that can't just be pumped up with a slider bar. For photos shot without any assistive lighting, it's facial details that suffer. Most notably, the side of the face hidden in shadow.

A standard way of lighting a photo or video is using "three-point lighting". This refers to the use of three separate lights to illuminate a subject: a key light, fill light, and back light. Without going into Strobist-levels of detail, I'll simply explain that a key light is your primary light source (and where the viewer can immediately identify as the light source), the fill light is a secondary light source to eliminate key light shadows, and the back light shines at a subject from behind, to separate them from the background. Without using a flash, you still have access to at least one of these types of lights. When shooting outdoors, the sun is going to be your key light. Indoors, angling a subject toward the most dominant light source does approximately the same thing.

The key light is something I always try to keep in mind when walking around events and taking photos. It's why I ask people to turn around and face a window or move out of a shadow-y area before composing a frame. But shooting with a key without a fill leaves uneven portraits. In the lead photo above, you can see the dominant light is coming in from the left side of the frame, which means the right side of the cosplayer Katie George's face is cast in shadow. That's where using Lightroom's Radial Filter comes in.

In Lightroom, I used the Radial Filter to draw an ellipse around the subject, and selected the "Invert Mask" checkbox. This means I would be able to adjust a layer of additional photo settings of everything inside the ellipse, which then stacks on top of the development settings for the entire photo. For these cosplay photos, I bumped both exposure and shadow detail up in the Radial Filter, which serves both the purpose of making the subject stand out from the background and also lifting shadow detail that's a consequence of having no fill light.

The end result is pretty good. The Radial Filter almost gives the illusion that there is another light shining directly onto the subject, since that elliptical area is up to half a stop brighter than the background. Only more discerning eyes are able to tell that this light isn't real--that there is still some uneven detail between light and shadow on the subject. But at a glance, the photo definitely pops more. You can see its effects again in the example below. Here, the key light is coming from outdoors through a window on the right. That leaves the left side of Cosplayer Gillian Owen's face in shadow, but we salvage much of that detail with Radial Filters.

This technique is far from perfect and is no substitute for legitimate fill lighting. For example, in this photo I took over the weekend, the shadows cast on the right side of little Bubs' face were pretty strong. A Radial Filter was able to even the lighting out somewhat, but there's still clearly a blotchy spot of shadow on her forehead. Even using color tonal adjustments to attempt to match that spot to natural skin tone and reduce the contrast only helped a little bit. Not being happy with this missed opportunity to snap a better photograph is a good reminder of the limitations of digital manipulation. There's only so much that Photoshop and Lightroom can fix; it's always better to get as close to your ideal photo in-camera than to rely on post-processing to make up for poor planning and skill. In my case, that means stepping up to using a flash ASAP.