How Soft Is Soft Light?

Rogue Crew

Rogue Crew

Well-known member
Straight to the point. I can spot the difference between a hard, focused light and soft light, but how "soft" is soft light?
• What is the scale here, or is it entirely subjective?
• Why can't acceptable soft light be achieved with the use of diffusion gels in front of your fixture instead of using a cumbersome and often expensive softbox? I would have thought that the ability for multiple layers of diffusion gels or combined diffusion and color correction gels with barn doors might give you a pretty good result.
• What about these lighting fixtures that look like a rectangular periscope and where the lamp/s are hidden in the bottom half and the top half provides a softer indirect light. Altman make a couple of models (See Soft-Lite http://www.altmanltg.com/prod_openface.htm); S-V makes one, others too. Do these fixtures just not cut it?

I'm not trying to pick any fights. This is an honest quest for answers, so please don't blast me for asking.
 
Re: How Soft Is Soft Light?

The softness of a light is determined by one factor only: the size of the source of light. (You'll often hear that it's also determined by how close the light is, but that's really just another way of manipulating the size of the light source).

Diffusion gels do not do anything magical to soften the properties of the light, other than to spread it around such that the surface of the diffusion is now the source of the light. In effect you make the diffusion gel become a glowing light source.

You do not "need" an expensive Chimera softbank to get a soft light source. Turn your hard tungsten light around (facing away from your subject) and bounce it off of a white wall, and you'll get a very soft (uncontrolled) light source. Bounce it off a sheet of foam core. Bounce it out of a photography umbrella. Or push it through a sheet of diffusion. Anything such that the result is a large, even, flat surface of light.

The expensive softboxes give you much more: they are black on the outer surface, so they control spill. They are lined with reflective material, to focus the output of the light. And the diffusion in front is designed to give an even, soft glow. Furthermore, on quality softboxes, that front will be recessed a couple of inches, thus giving a small lip of "barn door" control, instead of an uncontrolled glowing front. Furthermore, the softboxes will usually offer the ability to affix "egg crate" material to direct the light even better, thus controlling spill and keeping it off the background.
What about these lighting fixtures that look like a rectangular periscope and where the lamp/s are hidden in the bottom half and the top half provides a softer indirect light.
Click to expand...
All that's doing is combining a bounce card and an open-face light unit in one. It's a broadlight with its own built-in bounce card. And the bounce card (the white inner surface of the scoop) becomes the light source, instead of the pinpoint halogen bulb buried down in the base.

Those are often called "ziplights". The only problem with 'em is, they're a fixed size, and usually not that big of a size (especially the S-V units). The softness of a light is directly related to the size of the source, so a 36" x 36" Chimera softbox is going to be MUCH softer light than a 5" x 7" S-V ziplight. But the S-V ziplight will be much softer than a bare tungsten bulb will, with its tiny pinpoint of light.
 
Re: How Soft Is Soft Light?

[quote author=Barry_Green link=board=lighting;num=1087238418;start=0#1 date=06/14/04 at 12:00:17]The softness of a light is determined by one factor only: the size of the source of light.  (You'll often hear that it's also determined by how close the light is, but that's really just another way of manipulating the size of the light source). [/quote]

I would add that it is the size of your source IN RELATION TO the size of your subject. The larger the source the more the light wraps around the subject. The more the light wraps around the subject the softer the shadow.
 
Re: How Soft Is Soft Light?

One more thing:

We often get caught up talking about lighting instruments and how the light falls.

Step back for a moment and look where the light is not falling. Look at the shadows. For me, painting with light is really about placing shadows. It is very easy to light a scene, it takes skill to place the shadows.
 
Re: How Soft Is Soft Light?

I havent used umbrellas in a while but when I did, I used to have the light with the umbrella hiting the talent straight on opposed to turning the light around the other way and shooting into the umbrella. The outcome was a nice soft light. I guess what I am saying is you will get a nice soft touch either way you position the light on the umbrella.
 
Re: How Soft Is Soft Light?

I actually did a shoot last week and in a pinch we used one of those round collapsible 5-1 reflectors (take off the cover and its translucent) Put it in front of a 650watt and I was pretty surprised how good it worked. I know its nothing new.. but it was for me.
 
Re: How Soft Is Soft Light?

[quote author=CamOp link=board=lighting;num=1087238418;start=0#3 date=06/14/04 at 14:56:41]One more thing:

We often get caught up talking about lighting instruments and how the light falls.

Step back for a moment and look where the light is not falling. Look at the shadows. For me, painting with light is really about placing shadows. It is very easy to light a scene, it takes skill to place the shadows.
[/quote]

Yes. A picture is as much about what you don't see as what you do see, sometimes.

When you draw a picture of something, your pencil strokes are not the lit parts of the object, but the shadows. You're taking perfect, even light (white) and providing the shadows, the contrast. Only then does the picture form.
 
Re: How Soft Is Soft Light?

Amen to all that. The art of lighting is controlling where the light goes, and where it does not go.
 
Re: How Soft Is Soft Light?

I totally agree with the the light & shadow comments. Most of my favorite cinematogoraphy (usually in older films), paints high contrast light & shadow pictures and has almost become extinct, although there were some beautiful (old-fashioned?) interior shots in The Last Samurai. I'm not trying to be pig-headed, but doesn't the use of a softbox kind of wash out most of the shadow? Is this a legacy of television videography? I've read over and over, that if you want your work to look like film, light for film. So...
 
Re: How Soft Is Soft Light?

My wife was watching "Emma" the other day (Gwyneth Paltrow film) and I was just floored by how awesome it looked. And it as all hard light, bright highlights and deep shadows... looked utterly wonderful.
 
Re: How Soft Is Soft Light?

I love that picture, it's great -- but yes, that particular time I just happened to be going through the room. I haven't seen it in years, and the particular scene that was on was just stunning...
 
Re: How Soft Is Soft Light?

Well, my girlfriend watched "Joe Millionaire;" it just happened to be on this one time when . . . oh, and another time when . . . oh, and this other thing . . .

;D

But you're man enough to admit it, Barry! ;)
 
Re: How Soft Is Soft Light?

The softness of a light is determined by one factor only: the size of the source of light.
Click to expand...

Barry, that is simply not true. The directional quality of the light is just as important. For instance, a giant fresnel is a large hard source. To diffuse it, you would put a translucent material over it, cut to size. The size of the light doesn't get any bigger, but the quality of the light has changed.

To make a light softer without changing it's size, you diffuse the light by scattering it's light beams. When unidirectional light comes from a hard source and either passes through a diffusion material or bounces off a matte surface, the beams scatter and produce results that are sometimes described as "wrapping around" the subject. It's also depends on the reflective or matte qualities of the subject.

Another perfect example is a light I used to have called the Arrisoft 2000. This was a 2000 watt softlight that they use in TV studios and stuff. Anyway, to convert it from a soft light to a hard light, all you had to do was change the built in reflector from a matte white painted peice of metal to a semi glossy silver peice of metal. With this reflector, it was considered a "broad" light.

And if you don't believe me, I learned what I know from reading Ross Lowell and Ansel Adams.
 
Re: How Soft Is Soft Light?

Yeah, I was kind of boneheaded on that -- I was thinking only about the closer/farther situation, and ignoring that directionality is important as well. Which is why egg crate can be employed to make an existing soft light "harder". Doesn't change the source, but it changes the directionality, which makes the light "softer".

Good call.
 
Re: How Soft Is Soft Light?

Yeah, didn't mean to jump down your throat, but I just happen to know more about lighting than other areas of cimematography :P
 
Re: How Soft Is Soft Light?

No problem at all! I always look for the facts and the truth, and you called it the way it was -- my statement was not accurate, so please feel free to fill in the missing part! I don't want to be misleading people either... like I said, I blew it that time! :)
 
Re: How Soft Is Soft Light?

Technically, soft light is "diverging light." All light diverges, so the question is how divergent. A laser beam is about the "hardest" light you will find, because it diverges very little.

Softness can be measured merely by talking about the fall off ratio. An object occluding a soft light creates a "negative area" or shadow. In a very hard light, this negative area will be represented by a rapid fall-off. In a very soft light, because of the divergent nature of the light "particles" (photons) fall-off is very gradual.

Bouncing a light off a white board on a C-Stand is merely a way to increase the divergence of the light.

The term softness is in and of itself subjective. Thus what is soft to me may not be soft to someone else. Most people will agree that a fresnel on tight focus produces a hard light, while placing a silk butterfly in front of the fresnel is soft light.

You can express softness in terms of a fall off curve (x lumens lost over y distance), but people rarely do in my personal experience (may be different elsewhere). Which is why lighting is as much an art as a science. When I say to a dp that I want a soft / warm lighting scheme to simulate a fire which will allow me to shoot at f8, the dp will go off and basically take my subjective terms and make them reality based on his or her experience, in addition to "doing the math" to provide the exposure I desire.
 
Re: How Soft Is Soft Light?

You could attempt to scientically define levels of softness, but I think that would be a waste of time. It's kind of like saying how wet is wet and how dry is dry? I guess you could define hard with a lazer like the guy above said and you could define soft as the center of a translucent white dome completely surrouned by kino flo's ;D
 
Re: How Soft Is Soft Light?

[quote author=Tony_H link=board=lighting;num=1087238418;start=0#13 date=06/26/04 at 12:24:50]

The directional quality of the light is just as important. For instance, a giant fresnel is a large hard source. To diffuse it, you would put a translucent material over it, cut to size. The size of the light doesn't get any bigger, but the quality of the light has changed.[/quote]

So logically, you should be able to use gel/diffusion on the face of the fresnel, add more diffusion on a frame in front, but apart from fresnel and then focus to taste. Does that make sense?

So far, no-one has answered my question, how soft is soft? How do you measure it? How do you know when you've achieved it? As Tony's post suggests, there must be more than one way to achieve it.
 
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