What do photographers mean by soft light vs. hard light, and how do you control it?
Asked 6/8/2011
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I often hear people describe lighting as “soft” or “hard.” What do those terms actually refer to in a photo, especially in terms of shadows and contrast? What makes a light source appear softer or harder, and what practical ways can I use to change that?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
15y ago
2 Answers
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The hardness or softness of a lightsource is determined entirely by the number of angles light is coming from (not the number of angles it's going to, that is the spread of the beam).
A lightsource producing light from many angles will have the effect of filling in shadows, and provide a gradual falloff (transition from lit to shadow). This is because as a surface curves away from the light the number of illumination angles slowly reduces. Contrast this with a hard source which produces light from only one angle. As a surface curves away from the light there becomes a point where the single lighting angle is at 90 degrees to the surface so the surface is no longer lit, giving a hard cutoff.
The biggest factor in the hardness or softness of a lightsource is the relative size of the light emitting surface. Large sources are in general soft* as they have a large illuminating surface, and thus each point will emit light from a different angle. You can make a lightsource bigger by putting a diffuse translucent object infront (this is called diffusing the light), the light shines out of a hard source from and single angle, and is then re-emmited from the diffusing material at many angles.
Here a relatively small lightsource results in a hard boundary between the lit and shaded side of the object.
Here a relatively large lightsource results in a softer transition from light to shade as the light can still reach the far side from certain angles.
I say relative size, as it's all to do with the angles. If you move a large source further away, the range of lighting angles decreases. The ultimate example of this is the sun. The sun has a huge light emitting surface, but is very far away, so there's little difference in angle of incidence between light coming from the top and bottom of the sun. The sun is thus a hard source, as demonstrated by the hard transition from light to shade you get on a sunny day.
*large sources can be hard, if they have something to limit the number of angles light is emmitted from, such as a grid or snoot.
Originally by user1375. Source · Licensed CC BY-SA 4.0
user1375
15y ago
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Generated from our catalog & community — verify before relying on it.
“Soft” and “hard” usually describe the shadows a light creates. Hard light produces shadows with crisp, sharply defined edges and stronger contrast. Soft light produces shadows with gentler edges and smoother transitions from highlight to shadow, sometimes with very little obvious shadow at all.
The key factor is the apparent size of the light source relative to the subject. A small-looking source lights from fewer angles, so shadows are harder. A larger-looking source lights from more angles, filling in shadows and making them softer.
You can make light softer by increasing its apparent size or scattering it. Common ways include:
- using diffusion material or a softbox
- bouncing the light off a wall, ceiling, or reflector
- moving the light closer to the subject so it appears larger
- using naturally diffused light, such as an overcast sky
A classic example is the sun: on a clear day it acts like a hard source and casts sharp shadows; on a cloudy day the clouds spread the light across much of the sky, making it much softer.
Hard light isn’t always bad—it can be used creatively—but soft light is often preferred for smoother, more flattering portraits.
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