ASA by purchio

We’re finishing up our basics of photography with ISO, or film speed. This builds on our previous episodes on the pinhole camera, shutter speed and aperture.

ISO applies to film, but it translates to the digital world. ISO stands for the International Organization of Standardization. The word order is French. The standard for color negative film is ISO 1500:1987, for black and white, it’s ISO 6:1983. You won’t see those listed on film canisters, but these are the standards document references. The ISO numbers that we are used to are the arithmetic scale. ISO is also available on a logarithmic scale, but it less common.

High speed films (higher numbers) allow more light, but also have the potential for more grain in analog photography or grain in digital photography. Lower speeds (lower numbers) are less sensitive to light. On the digital side of things, ISO refers to the sensitivity of the image sensor to light.

Nikon Coolpix P6000 with SB-400 High Shutter Speed by littcool

Today our topic of conversation is shutter speed, continuing our media science series about photography.

Shutter speed refers to how long the shutter of a camera is open for. Shutter speed is closely tied to aperture. When talking about fast lenses, the shutter speed is what really makes a lens “fast”. As more light comes in from a wide aperture, the shutter speed can be shorter and shorter to accommodate capturing an extremely quick moment like a baseball being thrown or a hummingbird’s wings.

Shutter speed and aperture go hand in hand. When camera standards were decided upon, changing the shutter and aperture inversely would maintain the same amount of light in an image. This has changed a bit with digital cameras, but originally shutter speed options were in multiples (like 1/30, 1/60, etc.), so multiple properly exposed images could be created using different settings.

Here is an Flickr set as an example of photos of the same subject (fountains) at different shutter speeds: Shutter Speed Tests.

aperture by shoothead

Aperture is measuring using f-stops in a ratio or fraction. It measures the opening of the iris of the camera. In remembering our pinhole camera example, the aperture is how wide the pinhole is made. The f:aperture number means that the larger the numbers get, the smaller the hole is. The f stands for the focal length of the camera.

Playing with your aperture settings can produce some fun images. One example is bokeh images. For some great bokeh images, take a look at the bokeh Wednesday pool on Flickr. If you see anything that jumps out at you, leave the url in the comments.

Rob’s Flickr account
Chris’ Flickr account

09/06/2007 - Art Center College of Design by amayzun

A pinhole camera is a lightproof container with a hole on one side and a film plane on the other side. Together, the aperture, the shutter and the plane create a camera. Building a pinhole camera is a simple weekend project and instructions are readily available online. Kodak has directions on creating a pinhole camera on their website and so does Instructibles. The Instructibles directions are embedded below. To create the aperture, you can use this pinhole camera design calculator to get your proper dimensions.

The largest pinhole camera that we could find was created using an airplane hangar. Check out a photo of the finished photograph on Flickr.

How To Make A Pinhole Camera – More DIY How To Projects