Lighting Modifier Advice For New Studio Space

Started Jan 20, 2013 | Discussions thread
DecibelPhoto Contributing Member • Posts: 791
Re: Lighting Modifier Advice For New Studio Space

Sailor Blue wrote:

DecibelPhoto wrote:

Hey Sailor, I see you all the time in these forums, you have some great advice for people.

I'm curious though, why would you say that the main light source should be at least as big as your subject, and used at a particular distance? I see these formulas a lot, and they never really make sense to me. I work a lot with very well established editorial, advertising, and fashion photographers, and I would say that more often than not, that formula isn't followed. I almost never use 6" sources for full body shots.... Is this what you are recommending here?

Lighting for classical portraiture follows certain rules (perhaps guidelines is a better name). If you don't know the rules and how following them produces a result you won't know when to break the rules. Occasionally you should break the rules for a portrait, but generally it is best to follow them.

If you follow the rules on diffuser size and distance you get soft flattering light on the subject and you get a nice ratio of highlights to shadows to give the flat image of the subject a 3D appearance.

Soft light produces highlights and shadows with soft diffuse edges. Soft light hides and smooths small skin imperfections and softens the shadows that wrinkles cause, reducing their appearance. Good lighting can take 5-10 years off a subject's appearance.

The ratio of highlights to shadows is controlled by the inverse square law, i.e. light falls off according to the square of the distance between the source and the subject.

If you use a smaller portraiture light source you have to move it further from the subject to light the entire subject and the light becomes harsher with the highlights and shadows having sharper edges. With this increased distance the ratio of the square of the distances between the light source and the two sides of the subject drops and the light becomes flatter.

If you move your light source closer than about 1 diagonal/diameter to the subject the light becomes even softer but now the ratio between the highlights and shadows deepens as the ratio of the squares of the distances between the two sides of the face and the light source increases.

The rules evolved from balancing the softness of the light and the ratio of highlights to shadows.

Fashion photography is not portraiture. With fashion photography you want to show up the clothing, not the model. Fashion photograph is usually done with a smaller harsher light source than you would use for portraiture since you want to show up the drape and texture of the fabric, not hide and smooth skin imperfections. Showing up the drape and texture depends on having shadows.

Perhaps the most popular light modifier for fashion is the beauty dish. The beauty dish is in between a small very harsh light source like a hot-shoe flash and a soft light source like a softbox. The light from a beauty dish is from a fairly large surface but is more directional than light from a softbox.

Light from a beauty dish is great for bringing out the texture and drape of fabrics since it causes shadows from the drape and weave of the fabric, yet the shadows are not completely hard edged since the light source is fairly large. Of course a beauty dish must be used at a reasonable distance or it will become too harsh.

Just like portraiture, lighting for fashion is a balancing act between the softness/hardness of the light and the highlight/shadow ratio, it is just that a different balance is needed.

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Yes I understand what type of light following your rules creates, I just don't really agree with the concept of giving this advice.  I suppose it is a safe place to start assuming the person wants that look.  But I would argue that this isn't necessarily how classical portraiture is done, and there is no particular reason to assume someone does want that look.  There are certainly many who would use a harder light than you are recommending, and with well placed fill and lighting patterns there are many other options.

I especially think that the rule you offer breaks down when you mention the size of the light source in comparison to the area being photographed... it would make more sense to suggest a light source size in comparison to the size of the head, since this is generally the focus with portraiture.  Recommending a 6' box as a rule for shooting a full body is - although not wrong - completely unnecessary.

Also, you mentioned that "The ratio of highlights to shadows is controlled by the inverse square law, i.e. light falls off according to the square of the distance between the source and the subject."  Yes light falls off, but i would argue that the principal means for controlling the ratio of highlights to shadow is not by modifying the size or proximity of the light source, but rather through the use of fill.

The reason I asked about this, I suppose, is that in all of my years of photography school, assisting, and working as a professional photographer, I had never once heard of this "rule" before seeing it on this forum.  It is not something that has ever been in my conscience, nor the conscience of the well regarded portrait photographers I work with, and I'm not sure it helps to put it into other people's heads.  The concepts of relative light source size and it's relation the hardness or softness of light is very important, and I think it helps more to let people experiment with different qualities of light so that they can see how this effects the look of their portraits.  Locking people into a single quality (and not even one that most portrait photographers I know these days use) seems to be a little narrow sighted, even for beginners.

Again, I very much respect the advice that you give out to help beginners on these forums.  This is simply one thing I have seen you say on numerous occasions that I don't really understand, although I appreciate the clarification.  If it were me, I might present it as less of a rule and more of a method for achieving a specific style of "safe" portrait lighting that is no more or less correct than a variety of other methods.  Obviously giving beginners a clear direction to start with is very helpful, but I would propose that establishing that direction as "correct" can be misleading, especially since my own advice in the matter would often contradict that rule.

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