Wednesday, January 4, 2012

Light Painting Tutorial

If you’ve ever taken a photo at night with a point-and-shoot camera and noticed some blur, you may have wondered why it happens.  This often frustrating phenomenon has mostly been fixed by modern cameras touting little to no “shutter lag.”  Nevertheless, the first time I encountered motion blur, I thought it looked kind of cool, and created many desktop backgrounds for my computer just with “happy accidents” of blurry lights from motion shake. To understand why motion blur happens, you first must understand how cameras, and to some extent, how our eyes work.  We all learned in elementary school, how our eyes work right?  Light bounces off of objects, is gathered, controlled, and focused by our eyes.  The image is projected to the back of our eyes where a bunch of nerve endings send a signal to our brains that tell us what we are seeing.

A camera is simply a box with a hole in it.  You can also think of a camera like our heads, with the lens being kind of like our eyes.  Think of the opening/closing of a shutter like blinking an eye.  In addition, our pupils expand and contract to control the amount of light that enters our eyes the same way the camera aperture does for the very same reason.  Our corneas bend and refract light the same way the glass in lenses focus an image to the sensor or film at the back of the camera.  The nerve endings at the back of our eye are like the sensor in the back of the camera, which processes the image and you get a picture.  By the way, one of my favorite experiments as a kid was shining a flashlight close to my eyeball, and watching my pupils expand and contract in relation to the intensity of light.  Probably not good for the eyes in the long run, but I gained a complete understanding of how pupils work (they expand when there is less light, so that they can gather more light for us to see, and they contract when there is sufficient light).

Ok class, our science lesson is over.  Let’s move on to art! 

Cameras with the M (manual) mode will allow you to control the shutter (blinking) and aperture (pupil) during an exposure, and will allow you to do some pretty cool things.  Ever see a calendar full of waterfalls that look dreamy and fake?  Well guess what?  It certainly is dreamy, but it ain’t fake!  The smooth water that you see is simply motion blur of water.  The longer you leave the shutter open, the more blur you’re going to get.  

A fast shutter speed freezes motion. 

A slow shutter speed shows the movement of the water.
Let’s go back to the very beginning of this post, where I talked about blurry photos in a dark environment.  The camera is smart enough to know that you’re taking a photo at night, and as a result, it is purposefully leaving the shutter open long enough to gather enough light to make a picture that’s not completely dark – so if anything that is moving in front of the camera will be a blur.  In this case, waterfalls are constantly flowing, so they’ll show up as blurry if you leave the shutter open long enough. 

An exposure that requires that the shutter remain open for a long period of time is called a long exposure.  We’re all used to the sound of a shutter going off in a split second, but not too many of us are familiar with the concept of leaving a shutter open for 10 seconds, several minutes, or even hours.  Ever see a photo of a starry night that looks like the stars are swirling in a circle?  That’s the result of a long exposure over several hours, capturing the light of the stars as the earth spins on its own axis.  Go ahead, google it!

A long exposure requires that the camera be completely still, or else you'll get motion blur.  A tripod, or any type of grip gear that will hold the camera steady is necessary.  A remote trigger is also suggested, but isn't necessary if your camera has a self timer. 

Tripods, clamps, ball heads, and variable friction arms are all tools that help position and stabilize the camera.

Every time there is light registering through to the sensor, that illumination will show up in the picture.  If that light is moving, then you’ll see a streak of light.  That is the concept behind a genre of photography called light painting.  The term is derived from the concept of painting an image with light, with the canvas being a completely dark scene.  Anything that is illuminated becomes part of the picture. 


These light streaks are the result of dragging my iPad across the scene over a span of 10 seconds.


Notice the strobe in his hands, aimed back at him.

In the above photo, found a dark area at night and told my friend Sam to move from one seat of the car to another.  I set the camera shutter to stay open for about a minute.  Every time he moved seats, I would have him fire the strobe in his hand, pointed at himself, thus registering his image on the film because he was lit up.  The end result is 4 Sams in 4 seats, all taken with a single push of the button in one exposure. 

There are plenty of creative concepts that can be achieved with light painting.  One of the most creative videos I’ve seen is “light warfare” done by the awesomely talented FreddieW.  I simply don’t have the patience to piece together thousands of photos to create a single movie, and I’m sure lots of time was put into creating that.   Another cool light painting portrait I've seen is one done by Aurora Crowley of Austin Rivers for ESPN Rise magazine.  The final shot looks pretty awesome.

These streaks of light are the headlights of a car zig-zagging through a parking lot.

We stopped the car so you could see it.  If the car keeps moving, you wouldn't see it in the picture. 
This was created by driving a car around the cooper.   Notice the whites of the headlights and the reds of the tail lights.
I painted this scene with a small LED flashlight, held close to the wall and ground.  The shutter was open for 132 seconds.
The bottom line is that anything emitting light can be used as your “brush.”  Lasers, flashlights, ipods, phones, you name it.  By the way, if any of you has one of those Star Wars light sabers that were selling 5 years ago, I'd love to get in touch with you.  That would be an awesome tool for a light painting session.  Go ahead and give it a try, and feel free to share your creations!

-Johnny

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