What Is Photography?

The word “Photography” is formed from 2 Latin words, “foto” - which means “light”, and “grafis” - which means “control”. “Photography”, from this context, therefore means “the control of light”. This is essentially what a photographer does. The ‘light’ that enters a camera or imaging device is ‘controlled’ so that an image is produced & exposed to the desired result.

It should be noted that the term ‘correct exposure’ generally applies to images that don’t necessarily need or have any artistic license i.e. the image has a good overall balance of tones from black through to white. We’ve all seen the artistic type images produced by a photographer who has ‘bent’ the rules to create an image to their own preference & artistic slant.

In essence there are only 3 things that will affect the outcome of your captured image. The adjustment of any one of these will have a direct effect on the appearance of your photo. These are:

1) Sensor sensitivity (also known as ISO).

2) Aperture size.

3) Shutter speed.

Before I explain what these are, it is important to note that to create an image that ‘bends’ the rules, your camera needs to set in full ‘manual mode’ i.e. you should not leave the camera to make any decisions itself as it will always try to take a correctly exposed image. If this is what you want by the way then let the camera do it’s own magic & put in Automatic mode.

Ok, lets take the above in turn:-

ISO:

Prior to the onset of digital imagery, film based cameras were used. Film was manufactured by many many companys, some better than others. All film was manufactured to produce a specific ‘sensitivity’ rating (commonly known as film speed which should not be confused with shutter speed – 2 completely different things). The more common film speeds were ISO 100 up to in the region of ISO3200+. There were specialist film produced outside this range but these were used mainly by photographers with specific results in mind & would not generally be used by the majority.

Photographers would buy film based on their shooting requirements. The lower the ISO number the more light is required to take an exposure. For example, an ISO 100 film would require more light to expose (burn) an image onto it wheras an ISO3200 film would require much less light to expose the same image in the same conditions. For example, a sports photographer taking photos of a football match in a low lit stadium would probably opt for an ISO 600 – 1000 or something of that ilk to allow him to use what available low light there was but more importantly it would allow him to use a faster shutter speed to catch the action i.e. to freeze the motion of the players/ ball to create a pin sharp image. The downside with using a higher ISO film is that the images were prone to ‘grain’ or ‘noise’. For crystal clear clarity, ISO 100 would produce excellent results.

In this current day & age & with the advent of digital photography, film has been replaced with a ‘sensor’. These come in all shapes & sizes but effectively they all do the same thing & that is to record the image to produce a digital file. Sensors work on the same principle as film i.e. they have sensitivity ranges & also suffer from the same ‘grain/ noise’ problems as film does. Some of the top of the range digital SLR cameras have sensors with ISO ranges from 50-12000+ & can thus capture pretty much anything that needs photographing.

APERTURE SIZE:

An aperture is the size of the opening within the lens that lets light through to the sensor (digitally speaking). Common lens apertures used in photography are about f/2.8–f/22 or f/2–f/16. These are commonly known as ‘f-stops’. A lower f-number denotes a greater aperture opening which allows more light to reach the film or image sensor. The photography term “one f-stop” refers to a factor of ?2 (approx. 1.41) change in f-number, which in turn corresponds to a factor of 2 change in light intensity.

Aperture size is also used to control how much ‘flash’ light can enter through the lens when combining ambient light with fill-in flash. By ‘stopping down’ the lens (i.e. reducing the aperture size by selecting a larger f-stop number) this limits the level of flash light to the sensor.

You can create great images just by playing around with the aperture size. For example, to create those images that have the subject in sharp focus but the background blurred & out of focus  (to make the subject stand out), you typically would select a wider aperture (lowest f-stop number). On the contrary, if you need everything in focus then you would select a smaller aperture (higher f-stop number). This is known as ‘depth-of-field control’ or put another way ‘depth-of-focus’.

The aperture size is normally selected depending on the required ‘depth-of-field’.

SHUTTER SPEED:

All cameras have a ‘shutter’. A shutter is basically a ‘curtain’ that opens & closes at a pre-selected speed to allow the light from through the lens aperture to hit the sensor & thus create the image. Shutter speeds vary from minutes to milliseconds. Many camera have what they call a ‘bulb’ option which means the shutter is kept open until the user decides to take his finger of the button to close it (which can be a relatively long time). At the other end of the scale, shutter speeds can reach 1/12000 i.e. one twelve thousandth of a second (pretty damn fast!). The selection of a shutter speed depends on what your subject is i.e. if it’s a fast moving object then you would require a fast shutter speed to freeze the action. In low light, a fast shutter speed would require you to open up the aperture & possibly increase the sensor sensitivity to create a usable image. Conversly, if the subject is static then a slower shutter speed can be used along with a lower sensitivity & smaller aperture which would produce a much less grainy shot.

In flash photography, the shutter speed dictates how much ambient (not flash) light enters the lens so by combining a fast shutter speed with a wide aperture the ambient light would appear darker and the flash light would be more prominent.

So, by having your camera in manual mode & by playing with the ISO, aperture size & shutter speed you can create endless variances of images. By adjusting any one of these settings you create an advsers outcome of the image. It is great fun to play around with these to see what end results you come up with……more importantly, don’t ever be frightened by experimenting..digital photography allows you to take endless photos without costing a penny & has truly opened up the scope for creating beautiful images…