How to Use a Spot Light in Photoshop

If you're trying to create a realistic look for your photos, you'll want to use a Spot Light. This lighting style mimics the way light shines in the real world, obeying the physical law of inverse square falloff. The light beam spreads out in a cone shape, and the farther the subject is from the light, the wider the beam will be. You can control the amount of light, the type of shadow, and more with the Spot Light's various settings. The Spot Light's Transform tool provides interactive handles for editing the cone's position and angle.

Inverse Square

Inverse Square Falloff is a technique for creating realistic light falloff effects. Compared to Exponential Falloff, Inverse Square Falloff uses the light radius as a clamp, rather than as the extents of the light's travel. This allows for realistic light falloff, but it may result in overlapping Stationary Lights. This is a technique used to create light falloff effects with a small light radius.

Inverse Square Law is applicable to off-camera flash, window light, reflector, sunset, and other non-electric light sources. The principles of light travel are the same, regardless of whether they're electrical or non-electric. Likewise, doubling the distance from a window results in a seventy-five percent decrease in intensity. This is a convenient way to test the Inverse Square Law and its application to lighting.

The distance between a light source and its subject is inversely proportional to the amount of light reaching that object. This means that the amount of light reaching the subject will reduce by 1/4 to 1/9 when the distance is doubled. Cutting the distance in half will increase the amount of light reaching the subject. Because light has a fan-shaped effect, the closer it is to the subject, the more photons will hit the subject.

Inverse Square Law describes how light spreads from a point source. It doesn't apply to light sources that are infinitely small. The principle applies to large sources and to sources that are relatively close to the subject. Short-range sources, however, are not subject to the Inverse Square Law. For this reason, the Inverse Square Law can be very useful for making short-range lighting effects. For example, the Inverse Square Law is effective for guiding a spotlight's rays around a room without causing any glare or reflection.