Lighting the Moondoggie

This started as a comment for Penny's blog but quickly sprawled into something too big for there. And too big for here too, ha ha. Still here it is -


Hey Pen,

Just back from six pages of Dave's Moondoggie. First up I gotta say I'm with him in toto. That is, I (and my little dog too!) agree with him that the Apollo missions were bullshit. Humans have never been to the moon and I expect he's right in saying that they never will.

But a couple of his arguments are bullshit and I reckon he'd be better off dropping them. Which is to say, on the subject of shadows, ambient light, and second light sources, he's completely wrong. He declares he knows a lot about photography, but regretfully I'm going to have to trump him with my ten years in 3D. A 3D heavy will understand light to a degree way beyond any photographer. Sorry if that puts any photographers' noses out of joint but it's the cold hard truth.

As an example, I'll ask the question - has anyone got a glass of water with them right now? If you don't, go get one. Now put the glass on the table. Now pick it up. Now put it down. Repeat this a few times and watch the play of light and shadow on the table. In amongst this is refraction, reflection, and shadow. Sure enough, a photographer can play with this: he can have more or less; he can light it from different angles; he can add mood: dramatic, gentle, whatever - and then he shoots it and bills the agency $5000. Lucky him.


What he does not have to do is figure out how to make the light do that thing. The effect as such, is pretty much done for him. In 3D nothing is done for you. If I want those pretty 'caustics' in my glass of water scene, I have to make them myself. Subsequently it is the lot of the 3D operator to spend a great deal of time contemplating the nature of light and how it is passed from object to object. If I don't tell the assorted objects within my scene how I want them to do this, then they ain't gunna - it's as simple as that. There is no default 'just-do-whatever-nature-does' setting. Instead there is 'incandescence', 'diffuse', 'specular roll-off', 'eccentricity', and an endless array of jargonistic concepts that are the lot of someone who has to define the laws of physics for every single shot.

Hmm... it's like re-inventing the wheel every time, except we also have to re-invent the earth, and then explain to both the earth and wheel the existence of the other, and how they should view that. Welcome to 3D.

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Now - the behaviour of light: Dave declares that light can only reflect back to where it came from. Oh dear - wrong answer. It is the nature of light that when it hits an object (regardless of what direction it comes from) the light then bounces in all directions. If it didn't we wouldn't see anything. If you see a thing it's because the light that has struck it (from the sun, say) has bounced into your eye. Whilst the light from the sun is effectively parallel, it does not likewise reflect in a single direction, ie. into your eye and your eye alone. It bounces in an infinite number of directions, and thus into everyone's eye. That's why 50,000 people can sit in a cricket ground and regardless of whether the sun is behind them, or in front of them, or wherever, they can all see the action in the middle of the field.


Clearly this reflected light does not go into our eye as some kind of go-nowhere-else one-way trip. Light is a 'lady of easy virtue' that will bounce around and around. Thus the people in the cheap seats on the hill who are in direct sunlight can still see the lah-di-dah sorts in the member's stand who are in shadow. They are lit by ambient light - the light that has bounced into them from the ground, the other stands, and yes, the atmosphere in the sky.

Now, before anyone pipes up with how the moon doesn't have any atmosphere, let me cut you off and say you've grasped the wrong end of the stick. Whilst atmosphere, or more precisely clouds, can produce soft, multidirectional light, in no way is this the be-all-and-end-all of ambient light. A photographer who knows the difference between the hard light that strikes a person on a sunny day and the soft ambient light that strikes them on a cloudy day, and thinks that 'cloud equals ambient' needs to think again. Ambient light is merely light that comes from all directions instead of one. Clouds make this happen, sure, but so do lots of things. When clouds intercede between the sun and the object being lit, the light passes through the clouds and loses its hard parallel nature. The clouds are now the light source and the light it puts out bounces around in every goddamn direction and is thus reduced, diffuse, and 'ambient'.


But the fact is, we don't need clouds to do this. Let's go into deep space, way beyond the moon, way beyond anything. It's just me and my camera and a white volleyball (um, which I've filled with black sticky rice and egg custard to, a) stop it exploding with differential pressure, and b) give me a delish last meal before I die of the radiation). Anyway, under Dave's photographer-logic of atmosphere-equals-ambient, the ball will be dazzling on the side lit by the sun and in perfect darkness on the side not lit. Or it would be if I wasn't floating next to it. Bugger! It seems like the light bounces off me and acts as a 'fill'. Sure enough, my white space-suit acts as a variety of mirror that reflects light back at the volleyball. In precisely the same way that light strikes the ball and bounces in all directions (one of which is into my eye), the light will also strike me and my white space-suit, and bounce in all directions (one of which is into the volleyball). The Dark Side of the Volleyball will be lit, and atmosphere ain't got nothin' to do with it. (Nor Pink Floyd, ha ha).

I will reflect light into the ball and the ball will reflect light into me. This would be vaguely directional sure, rather than truly ambient, but... if we had enough astronauts and enough volleyballs, and all floating in the middle of nowhere like some mad, drug-fuelled outer space sticky rice and egg custard wig-out... deep breath... in the centre of that would be true ambient light bounced in from all directions. And all without atmosphere.


And so! There we are on the moon, and we're shooting the other astronaut who happens to be standing in complete shadow. Beyond him in the background we can see the surface of the moon. Which is to say, direct light is striking it and bouncing in every direction, one of which is into our eye. If we see it, it must be so. Okay, and since it's bouncing in every direction it must bounce at him also. And of course, from him this weakened light must likewise bounce in all directions, one of which will be into our eye. It cannot be any other way. And yes, there is no atmosphere but it doesn't make any difference. Light does not need atmosphere to bounce around and behave in an ambient fashion.

With the surface of the moon acting as an ambient light generator, a matt black object will bounce (reflect, same-same) very little ambient light back at us, but a white object will reflect quite a lot. And of course a fully reflective metallic foil object will bounce nearly all of it back at us. And sure enough, it's all right there in the photo just as it should be. And whether we're on the moon, in the studio, whatever, it doesn't make any difference. The ambience is no proof of anything one way or t'other.

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And then there's the shadows, particularly those in the photo of the two landing pads on the 'lunar' surface. I'll happily concede that it isn't the lunar surface, and is in all likelihood cement dust sprinkled on the floor of the Lookout Mountain Studio in Laurel Canyon. But what I will absolutely not concede is that there are two light sources in this picture. Believe it or not, there is only a single light source and all the shadows accord with it. As head of 3D my job was precisely to look for errors of this nature and this picture hasn't got any. The foreground grey stick is square to us and about twenty degrees from the ground. The background leg is not quite square to us and maybe 75 degrees to the ground. Their shadows, along with those of the bumps in the extreme foreground are exactly right for a single light source, camera-right, and elevated at approximately 45 degrees.


I swear to God - professional reputation, the whole thing - this photo is halal. Without a shadow of a doubt (ha ha), I could build this scene in 3D and prove it utterly. It'd be the big don't-argue from hell. But to be honest, I couldn't be fagged. And besides what would I be proving? That the guys who faked these photos were smart enough to do the sensible and obvious thing and use a single light source? Shake my head - what a waste of time...

Besides that, if there were two light sources, we'd see one of two things: a) some of the objects would be lit from two directions and cast two shadows; or b) with the foreground objects and the background objects having each their own separate hard lighting, between them in the mid-ground there would be either a double lit area or a band of shadow - pick one. Blending two lights in this fashion is murderously difficult. I've tried to do it and it's a fool's errand. No one would waste their time.

And besides, take a look at this shot - what's the fucking point? Two landing pads occupying a small area of ground? Big deal. It's hardly a hero shot, and it could easily be lit by one light source, and so... why wouldn't you? Why bother with two lights? Sure enough, it is lit by a single light source. Me, I haven't got any kids but I'd be perfectly happy to swear on the lives of someone else's. Or is that too ghoulish? Hell, just take my word for it.

Oh! I tell you what - if anyone feels really confident on this shadow caper, like really, really confident, like 50oz of gold confident (all the money I have in the world), and wants to put their money where their mouth is, I'll take that bet! I'll dig up my 3D Maya license, clock up a day's labour, and Baby, I'm a Rich Man, Yeah!

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Mind you, I wouldn't feel good about taking that money. I'm not that cruel and besides, in the big discussion I agree with Dave. Previously I'd never had much time for the Apollo Hoax crowd and that was mostly due to the chronic nature of the wrong-shadow/ambient-light argument. Happily Dave attacked the whole Apollo question in his usual brilliant holistic fashion and I'm now on board. But as I progressed through his moondoggie piece, the head of steam that had built up (of the 'Go Dave Go!' variety) all came to a grinding halt once the dreary specifics of the lighting kicked in. Bugger! We were rocking and rolling and now it's all fallen flat!

Dave! Ditch those two photes mate! They ain't doing you any favours!