Photography 101 - Crash course in long exposure. (Patreon)

One of the most difficult concepts to understand when working with a camera is long exposure photography. 

The basic concept is this: 

Your camera shutter opens, and rather than closing within milliseconds like a normal photo, the shutter stays open for an extended period of time. (Determined by the photographer)

The result of which are photos in which all incoming light are recorded on the camera's sensor or film. It's sort of like filming a movie, except instead of capturing motion across many "frames" or images, you capture movement on a single frame.

Let's have a look at the above photo and consider how it was accomplished. 

• The camera was placed on a tripod and activated with a remote
• Settings are: "Bulb Mode" for shutter speed (the remote both opens, then later closes the shutter), F16 aperture, 100 ISO
• Focus was obtained and then locked in so that the camera would not hunt for focus every time a photo was taken. 
• All lights in the room are turned off, this is VITAL. These were taken in pitch black darkness.
• The model must remain at the same distance from the camera once this has occurred if you want your subject in focus. 
• The shutter is opened
• The flash is fired from a device I built which looks like this, from here on I'll refer to it as a flash tube:

The flash tube is intended to limit the amount of light that is exposed when the flash is fired so that the only thing the camera detects is a very limited area determined by the pattern loaded on the front of the tube.

• The first flash is fired towards the models face
• The tube is then moved down towards the models butt and fired again
• While holding the flash tube I moved to the left side of the model, this is the streak you see on the left side
• The flash is fired one last time towards the models face
• The camera shutter is closed.

All in all this process took about 5 seconds or less, the only light that the camera is able to pick up on is when the flash fires, this is what allows me to freely move between the camera and the model to get to the other side without my image entirely ruining the photo. 

Tips:

• Once the shutter is open, the model needs to remain as still as possible if your goal is to have her in focus. 
• The darker the better, even tiny luminescence will become bright with slow shutter speeds
• Movement is not entirely bad, it will simply be shown
• This technique is commonly used for things like writing in the air with sparklers or flashlights
• If you constantly move you will not be picked up beyond some basic ghosting. A lovely example of this is a photograph from early on in the development of photographic technology:

 This photograph depicts the Boulevard du Temple in Paris; while it may appear empty it is actually a very busy scene!! The only figure you see is that of a shoe shine working on a person's shoes. The reason for this? All of the foot traffic was moving!! Only the shoe shine and man were standing still for long enough for the camera to capture their shadows, this is because they were blocking the light coming from the sun reflecting off of the sidewalk towards the camera. Since everyone else was moving, the light was able to be captured over time, since scenery is largely still, it is all captured in great detail.

A couple other examples:

In this example, the flash was fired each time the model moved into a new pose, with 3 poses total.

In this example, the model was completely still while I walked behind her with a stick shaped flashlight pointed towards the camera. Note how I am not visible even though I walked through the entire frame of the shot. This is because the light was facing away from me and I continued moving. If I had stood still for a moment you would have seen a ghostly image of me develop on the sensor.

I hope that you've enjoyed the first installment of Photography 101! Please let me know what other techniques or ideas you would be interested in learning about!