Photo Skills A: Research

Research

APERTURE

Aperture Defined

According to www.merriam-webster.com the definition of aperture is as follows:

ap·er·ture (āp’ər-chər) – noun – a : the opening in a photographic lens that admits the light b : the diameter of the stop in an optical system that determines the diameter of the bundle of rays traversing the instrument.

How it works

The aperture is like the pupil of an eye. The aperture blades make the opening bigger or smaller, just like the iris makes the pupil dilate larger and smaller to allow in more or less light. In a dark setting, the iris opens up to let more light in and in a bright setting, the iris closes down since not as much light is needed to see any surroundings.

A camera has a lens with a diaphragm that opens and closes based on the lighting, automatically or manually, in order to regulate the amount of light that reached the film or sensor.

Nevertheless, in a camera, there are other factors that work with the aperture to control the exposure such as shutter speed and ISO, but the basics of aperture by itself are much like the eye.

How it is controlled

The aperture settings of a film camera lens, whether a 35mm, medium format, or large format camera, is set by what are known as f-stops. All lenses are marked with specified f-numbers, which are numbers marking the ratio of focal length to the diameter of the hole. The lower the f-stop number the larger the aperture hole becomes, allowing more light in to expose the film. Conversely, the larger f-stops numbers equate to a narrower hole.

Large f-stop = Small opening

Small f-stop = Large opening

Aperture and Depth of Field.

Aperture has a big impact upon depth of field.

Depth of Field is that amount of your shot that will be in focus. Large depth of field means that most of your image will be in focus whether it’s close to your camera or far away.Small (or shallow) depth of field means that only part of the image will be in focus and the rest will be fuzzy.

Depth of field is determined by the aperture and the length of the lens. The larger the aperture, the more light enters the lens, and the smaller the depth of field. Similarly, when using a long lens the depth of field is smaller.

SHUTTER SPEED

Definition of Shutter Speed

According to http://www.digitalrebellion.com/glossary.htm#S , Shutter speed
The amount of time it takes for the camera shutter to open and close. Faster speeds produce crisp motion and slower speeds produce motion-blur.

How it works

At the back of the camera, there’s a sensor that records light. This sensor is jam-packed with light-sensitive gnomes who do nothing but wait for light to hit them and then record whatever light they see. Most of the time these gnomes are very bored, because there’s a curtain in front of them that blocks out all the light. That curtain is called the shutter .If the shutter is open for a long time, a lot of light hits the sensor gnomes. If it’s only open briefly, the gnomes get correspondingly less light. The amount of time the shutter is open is called, shutter speed.

Shutter speed is expressed in fractions of a second, and is most commonly in the range of about 1/30 sec to 1/500 sec, though it can range from many seconds up to the maximum speed of your camera– frequently 1/2000 or 1/4000 of a second.

Shutter speed can be used to display motion in photographs. If you use a really fast shutter speed, you freeze whatever action is happening. Using a slow shutter speed will let you capture motion blur.

Shutter Speed and Aperture

As mentioned above, shutter speeds and apertures each have a standard series of settings called "stops".

With shutter speeds, each stop is a second or more, or a fraction of second indicating how long the shutter is open.
With apertures they are f/stops indicating the size of the opening through which light enters.