DON'T MISS: Italian conceptual portrait photographer Sara Lando is coming to the US to teach in Atlanta (8/16) and Baltimore (8/23). Highly recommended.

Sunday, April 02, 2006

Reverse Engineering Other Shooters' Light


So, you've worked your way through most of Lighting 101 (seriously, you're in the home stretch) and you are hopefully starting to get a grasp of basic photographic lighting.

You might not think you are an expert, but you also bring a lifetime of subconscious light analyzing experience to the party. When you see someone standing out in the sun, you pretty much know where the sunlight is coming from just by instantly processing the way the surfaces on their body and face are reacting to the light.

You know whether it is a cloudy day, or a sunny one, or noon, or late evening or whatever. So really, you are reverse-engineering light all of the time. In this same way, you can learn a lot about how a photograph was lit just by looking at it.

That's because light has to obey the laws of physics. You cannot hide how you lit something. Everything about the light — style, color, direction, size, beam spread, etc., — is on display for any shooter with the willingness to figure out.

It may take a little effort at first, but you'll get used to it. And stick to fairly simple photos at first, or just try to reverse-engineer the main (or "key") light in the frame.

True, sometimes photos will be composites or heavily Photoshopped and the light won't make sense. But don't feel bad, as that is likely more of a bad reflection on the photographer who shot the photo than on your engineering skills.




Sometimes when you are creating light you want to have a logic to it. That is to say, you are creating light that could have existed and makes sense. That's the case in the fencing photo, above.

But sometimes you can go off the beaten path and create light that has no real logic but just looks cool, or theatrical or even ethereal:



The key light in those two photos is the same — a speedlight stuck in a large paper Japanese lantern and suspended overhead by fishing line. But the fencer light is believable and logical and the soprano in the woods is more theatrical. I.e., that light is probably not really going to exist in the woods at night.

Either way, most of the time you should be able to analyze and figure out the light that has been used by others. Just look at it and ask questions.

Here are some starters.



Q: What direction is the light coming from?
A: The shadows will tell you.




Q: Were there multiple sources?
A: (Okay, this one is pretty easy.) If the light appears to be coming from multiple places and/or directions, yeah, probably multiple sources. As you progress further into lighting, you'll likely become interested in using multiple lights.




Q: Is the light falling over a small, restricted area?
A: Suspect a snoot, or a grid.




Q: What is the easiest way to check the style of the front light in a portrait?
A: Reflections in the subject's eyes will tell you a lot about the frontal lighting:




Looking at photos can intuitively tell you other things, too.

Q: Was the light nearby?
A: Check how fast it falls off as it travels across the subject. Falls off fast? Probably pretty close. Falls off slowly or not at all? Probably further away.

Q: Do the highlights transition smoothly to the shadows?
A: It was probably a soft light source. Hard transitions signal harder light sources.




Q: Is that light strobe or continuous?
A: Trick question. Unless there is movement over time involved, you can't tell. Light is light. And you'll learn to use that to your advantage.

For instance, in the photo above (which was taken in a nearly pitch-black room) there are six light sources: a flash on his face, another filling the entire scene and two in the rafters bouncing off of the wooden ceiling. The other two are the fire and the red-hot metal he is working on. Those count, too.




Q: Whoa, how did they get that overcast sky so neon blue?
A: Set the camera balance to tungsten, which renders the formerly neutral clouds blue. Underexpose the sky (to, say, a stop below medium grey) for more of an effect. Then, CTO-gel the flash lighting your subject to render the light hitting it as white and you have the effect. Boom, instant moody atmosphere.

There are no secrets when it comes to light. Only physics.

And as for the light bulb image above, it was done completely in-camera — no Photoshop. If you want to take a little side trip and see how it was done, check out the On Assignment post on this image, here. (It will open in a new window, so you can close it and get back to Lighting 101 when you wish.)


Next: Pre-Visualizing Your Light


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16 Comments:

Anonymous singlo said...

Enjoy your pages! Just add one point. We can guess the type of light modifiers by looking at the specularity of the highlight, shadow definition, shadow contrast and edge transfer. Sometimes we can work out whether the modifier is a Fresnel, grid reflector, softbox or beauty dish..etc by observing above features.

May 15, 2006 7:43 PM  
Blogger David said...

Singlo-

Do I sense another Dean Collins Finelight Video fan in the house?

May 15, 2006 8:22 PM  
Blogger RaNGeR said...

Hmmm... pretty cool photo of the light bulb! That'd be "110v AC" right? And although it looks like it's switched on there's no obvious connection to it. Kind of "floating" one might say. One might also say that it looks like it's lit by a couple of, hmmm, long soft-ish lights; one either side?

Almost looks like a good use for a couple of those DIY macro strip lights... ;)


Unless of course I'm totally way off the mark and its not switched on at all... just lit by a heavily snooted low-power CTO'd flash. :P

March 10, 2007 5:40 AM  
Blogger RaNGeR said...

BAH! NOW I get to the article where you actually tell us about that lightbulb. And here I was thinking I was being clever! :P

March 10, 2007 7:06 AM  
Anonymous Racertim said...

David- just wanted to say a massive thankyou for this. I've been reading your strobist articles for about two months now and was starting to think It'd never sink in but today I had an epiphany moment when I was brousing some galleries on another site and it all clicked!

I realised that i'd looked at a photo and found myself thinking. "I like that he's obviously used a snoot to backlight etc" didn't know I'd learnt so much I had no idea about before stumbling across this site.

Cheers,

Tim

April 25, 2008 7:54 PM  
Anonymous Ben DeCamp said...

David-
Any chance on seeing some neon-blue sky examples? Thanks!

June 17, 2008 12:33 AM  
Blogger Jeff Gaines said...

Could someone please explain "a stop below medium grey." I have been shooting for a while now and I have not heard the term in the context of exposure.

Thanks,

Jeff

August 10, 2008 3:25 PM  
Blogger Jeff Gaines said...

Could someone please explain "a stop below medium grey." I have been shooting for a while now and I have not heard the term in the context of exposure.

Thanks,

Jeff

August 10, 2008 3:26 PM  
Blogger Andy said...

Medium grey is the exposure your camera's light meter will consider to render a scene as 'correct exposure'. The exposure meter will measure the whole scene and based on the average reading it reads (considering highlights and shadows) it will suggest an exposure that would be equivalent to what is known as the mid-grey / medium grey / 18% grey exposure.

To explain that differently, if you had a scene with lots of dark shadow areas, the camera would guess at an exposure which would effectively raise these to mid-grey and can make the shadows look washed out (in this case you may compensate by reducing the exposure to render dark areas as darker).

I think what David is referring to in this example, is you would measure a correct exposure for the overcast sky (which would generally be bright) and then further reduce it by one stop to darken and emphasise the effect we are going for. When you take the image with strobe you would have a dark sky rendered blue by the white balance setting whilst the subject would be exposed correctly and at the right colour.

I think I've got the right end of this one and hope that explained it properly!

August 11, 2008 1:53 PM  
Blogger Petevideos said...

I was thinking maybe `David lit the bulb with another snooted flash on top directly, to make it seemed like it's on, but I don't think it would be so well lightened. It's more likely to be connected to an AC, and cables were hidden from the back. That seems more likely to me.

February 03, 2009 5:03 PM  
Blogger MarcusPV said...

This is a beautiful shot of a rather mundane object. First the easiest light to decipher is the white light coming from below on either side of the bulb. Judging from the shape of the specular highlights, I'd say the source is simply two naked strobes at low power placed on 45 degrees to either side. about 4 feet away from the bulb.

The most puzzling to me is the light of the bulb itself. First, the warm, buttery glow is unmistakenly incandescent, as opposed to the sickly blue/green of flourescents. What is really confusing is the modelling and shadow on the bulb itself, which couldn't happen if the bulb were actually turned on and producing light. My best guess is the bulb is "painted" with a smaller light in a long exposure. The light seems to be coming from within the spiral of the bulb, so it might have been something as small as a white christmas light dropped into the middle of the spiral, or just a flashlight coming through from the back.

This leaves two main questions. First, how is the bulb supported? Either it's mounted on a stick coming through the background, or the stand was wiped out in post. Second, how did you get the backlight to be the same shape as the bulb instead of just going oval? I would guess a snoot with a bulb-shaped gobo, but this would be much easier to fix in post production photoshop.

Is this close at all?

October 19, 2009 7:36 PM  
Blogger cmh said...

I'm looking at the same type of bulb and the bottom looks different. I'm wondering if the white area at the very bottom of the bulb is the mount and possibly the fixture that it is screwed into. Could it be a sconce coming out from the wall? Which means the bulb is on.

January 30, 2010 3:08 PM  
Blogger Mikey said...

Lights are almost directly to the sides (not from below, as one person guessed.) This is shown by the two bright spots (one right below the "FC" on the label.) Reflection off the back sides of the base and bulb would cause the backdrop to also be lit in the same "bulb" pattern and gobo's on the lights would prevent direct light from hitting the backdrop. The lighting on the glass tube itself does have me puzzled a bit.

December 01, 2010 2:26 PM  
Blogger James said...

I think this was done with two naked flashes on their sides placed in a cross lighting setup. Both flashes very close, just out of frame but on very low power, the left a half a stop lower than the right.

The bulb is lit from above with a snooted, heavily CTO'd strobe directed into the core of the spiral and the background is lit with another short-snooted or fully-'zoomed' strobe from beneath directed up at about a 30 degree angle at the backdrop.

I doubt it's your style to Photoshop out a stand so I am guessing the bulb is suspended somehow using a fine chord, fishing wire or the like?

Tell us Mr Strobeman! :)

December 16, 2010 10:04 PM  
Blogger Jock said...

For those unsure about how this was done have a look in the On Assignment area: http://strobist.blogspot.com/2006/06/developing-idea-part-2-compact.html

January 11, 2011 4:13 PM  
Blogger Jock said...

For those who want to know how this was done, see the On Assignment area: http://strobist.blogspot.com/2006/06/developing-idea-part-2-compact.html

January 11, 2011 4:14 PM  

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