Lighting Basics: Hard Light and Soft Light

I’ve decided rather than doing one massive lighting tutorial I’ll be doing sections of it and uploading them as I finish. I’m going to have two sections for these, “Lighting Basics” will explain the what, the how and the terms needed, and “Lighting Tricks” will be ways to implement these. So without further ado, here we go.

When using strobes off camera (Or in some cases on) you can usually choose whether an image will use hard or soft light. This is controlled by what kind of modifier you use, hard light will occur as the result of snoots, bare-bulb and unmodified speedlights, and soft light can come from large, close modifiers such as softboxes, silks and umbrellas.

How do they work?

Softness of light is affected by increasing the apparent size of the light source, you can do this by:
a) Increasing the size of the light source (Usually through diffusion through a modifier such as a soft box or umbrella).
b) Bringing the light source closer to the subject.

Hard light behaves in a way we are likely more familiar with, think of making shadow puppets in front of a movie projector, due to the small apparent light source your fingers cast strong, defined shadows on the movie. You may also notice the shadows become even more defined as you move your hand further from the projector (Thus giving a smaller apparent light source). If for whatever reason you don’t have a projector available you can try this exercise with a torch.

Soft light is a little more tricky (I’ll explain this more thoroughly at the end of the article), however to create a soft light source try having a friend hold a torch with a sheet of paper about twenty centimeters infront, and then look at the shadows cast when trying to make the same shadows, you should notice that the shadows are soft edged and less defined. You may also notice that you can alter the definition of the shadows by changing both the subject to background distance (Hand to wall) and the source to diffused distance (Torch to paper)

Soft light:

Reflector umbrella camera right, no elevation.

In the majority of applications soft light is preferred, it wraps around the subject leaving only subtle shadows with strong falloff.

Soft light is used almost exclusively in beauty portraits as it gives soft shadows which diminish wrinkles and give a soft glow. Due to it’s ability to introduce light without creating shadows soft light is often used as fill, you may notice fashion photographers with a massive PLM behind the camera to fill all of the shadows uniformly to a certain brightness without giving any indication of a second light source. For similar reasons soft light is often used in combination with natural light  as it will not likely introduce any further shadows.

It is important to remember that it is the apparent size of the light source which affects the softness of a light source, by this logic a Pringles can may be used as a soft light source for macros, whereas the Sun is a hard light source due to being so far away.

Natural light is not always a hard source however, on overcast days the clouds diffuse the sun resulting in more even shadows (You can even get to the point when you can look at a shadow without looking up and tell if it’s overcast)

Hard Light:

Barebulb source above and camera left

As David Hobby said “There is nothing inherently wrong with hard light at all. The problems with our bad early experiences were largely the result of bad light direction (as in “on camera”) and truly horrid lighting ratios (as in “nuke ’em ’till they glow.”)”

Whilst less flattering, hard light can create very stylized images and is often much brighter than soft light due to not needing to be diffused, the result is hard light can be thrown over longer distances and can be brighter if extra light is needed or the ambient needs to be darkened.

Hard light is often used as the key light, it imitates that of the sun and gives natural and believable light which you can control. I’m a big fan of using a single barebulb flash from above and angled towards the subject. You may also want to combine this with a reflector for soft fill.

multiple hard stage lights (Notice the many catchlights) resulting in rather complex shadows.

Which is best?

Soft light vs hard light is the same as wide vs small apertures and slow vs fast shutter speeds, it’s all up to your judgment of what look you’re going for when shooting. Whilst generally hard light is used to create stylised noir like images, and soft light is used to create even, beautifying images, however this is in no way a rule, and photographers such as Dean Collins have shot wedding dresses with hard light.

A more complex explanation (Inverse square):

The good thing is, light follows what’s called the Inverse-Square law, which goes something like this:

I = \frac{P}{A} = \frac{P}{4 \pi r^2}. \,

or “the intensity of light radiating from a point source is inversely proportional to the square of the distance from the source.

What this basically means to us is that as the apparent size of a light source increases, so does the amount of falloff and the spread. The important thing to understand is that light doesn’t care what’s in the way, it just keeps expanding, lets try to explain this visually:

For this hard light source the spread of light is fairly contained, however when the light is interrupted, the light surrounding it continues to spread in the same fashion as it did emanating from the light source. Soft light works by greatly increasing this spread:

This becomes important when you think of the interruption as a nose or a wrinkle, if the light is sufficiently soft it will fill itself in an give a “wrapped” look, however hard light will cast a defined shadow.

If you’re still a little stumped try looking at the angle at which the light spreads, notice the shadows fill in at the same angle that the light spreads, this is because when light is diffused to spread a certain way, it will constantly spread that way.

Edit: Kim Aldis provided this addition to the diagram to show the way the light spreads. It also shows that my diagrams were a little off but hopefully it should make a lot more sense from this. Thanks Kim.


4 thoughts on “Lighting Basics: Hard Light and Soft Light

  1. It might help your umbra/penumbra diagrams if you extrapolated some lines from the edge of the light source past the subject to the surface being cast upon. Just a thought.

    • Will do, I’ve been considering using a bit of a gradient to show the falloff aswell.

      One thing I will say is that the distance between the interruption and the surface can be as little as the distance between the chin and neck or even the space of a wrinkle.

      Thanks for the input 🙂

  2. Pingback: 94 Photography Links That Rock » Beauty life

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