Light Painting (while pregnant) - Smarter Every Day 41

Hey, it's me Destin. Welcome to Smarter Every Day. So, most women get pregnancy photos and then a couple of months later look at them and say, "What the heck was I thinking?" But I've decided to bring my wife here to a spooky abandoned warehouse. Yeah, it is a spooky abandoned warehouse. And, there's a guy named Wes Whaley, and he is a light painter, one of the best ones I've ever seen. Anyway, he lives close to me, so I contacted him and said, "Hey, can you do some pregnancy photos for me?"

Anyway, so today on Smarter Every Day, we're gonna teach you about light painting. Are you excited?

• Yes.

Behold the sexiest pregnancy photo ever made. [laughing] [music]

OK, so this is your camera shutter, and the camera shutter opens to reveal an image sensor. And this image sensor is made up of several pixels. Now, any time photonic energy hits the image sensor, the sensor converts this light energy into electrical energy. So we're gonna illustrate that by blasting me with photons. So can you blast me with some red photons? Woo! Alright, there you go. Keep blasting away.

So as she's blasting, I'm gonna take these… You got 'em in my shirt. This red and green photon energy, and go ahead, good job. I'm going to slowly deposit this yellow light, which is red and green mixed, into the top left corner here. So basically, all the energy that goes into the image sensor, as long as it gets there before I close the shutter, then that's what your image is gonna look like. So you can see we have some red and blue, but up here we have yellow, which is a mixture of green and red.

So, that's how light painting works. You expose the sensor. You add light, as if it's paint on a canvas, and then you close the shutter. Now, the one flaw in my metaphor here is, a real shutter doesn't open like this. Last week, with the Phantom high-speed camera, I showed you that the shutter opens from one side and then it closes from the same side. The reason it does that is you want a uniform exposure on all the pixels.

So, talk about the sensor now. So there's two main types of image sensor. The first one is a charge-coupled device or CCD. Now, CCDs are uniform, and all they do is they take…

• Are you done with the particle waveform analogy there? Can I have one?
• That's done.

Oh, that's a good one. This is blue? Alright, so light is a particle and a wave. So as the light comes in here and hits the sensor, you get an output voltage. That's how a CCD works.

However, a CMOS sensor, which is a complementary metal oxide semiconductor, is a little bit more complicated. It has on-board circuitry that processes each individual pixel as it's being exposed. So the problems with this are that you end up having a little bit more noise, and it's a little bit more expensive to make these chips. However, they're getting really good at factoring all this stuff out.

So CCDs are typically used for really low noise applications at really low cost. CMOS chips are usually used in things that need to have a very tight form factor, so a lot of the stuff is done on the chip itself and you don't have to have auxiliary circuit boards.

So, as you look at the rest of Wes's work here, just think about this: As the sensor is exposed, it doesn't matter when the light gets there. If you have a 3-watt laser over here that blasts for a nanosecond, it might be equivalent to a really low power LED dimly shining over here. That's why you can light paint without actually showing up in the image. [music]

If you want to learn more about Wes and what he does, just go to the video description down below and click on the link going to his Flickr page. He's got a lot of cool stuff on there, and I chose not to video some of the stuff he does, cause he's a little mysterious, and I don't want to give up his secret sauce. But if you want to try to figure it out, go check him out and contact him. Get Smarter Every Day. Have a good one.

Hey, all the songs that have been used in Smarter Every Day videos so far are all together in one album. I'll put the info in the video description. Hear you. Go ahead. Catch a photon!

If you can get a laser, then tie LEDs to your dog, and then you can shine a laser and make your dog chase the laser, and get a good image that way. There's all kinds of good stuff you could do.

[Captions by Andrew Jackson] Captioning in different languages welcome. Please contact Destin if you can help.