Digital Photography vs Classic Photography

Digital photography is a revolutionary new way to take pictures. However, it is very much based on traditional photography and uses many of the same principals. Both types of photography need a lens to focus the light and a shutter to allow the light to enter the camera. The difference between digital and traditional photography is how the image is captured.

Digital photography uses an electronic sensor to capture the image. The sensor is made up of millions of individual ‘pixels’ which convert light into a number. Rather than waiting for the picture to be developed, digital pictures can be seen almost immediately on the viewfinder of the digital camera.Traditional photography uses film which must be developed in a darkroom using various chemicals. The developing process produces ‘negatives’ which must be printed before you can see the picture.

Digital photograph quality depends a lot on how many pixels it has. The number of pixels is sometimes referred to as the ‘resolution’ of an image, and can be expressed as a dimension (800 x 600), or the number of pixels per inch. A common resolution for computer screens is 800 x 600 and this means the monitor can display 800 pixels from side to side and 600 pixels from top to bottom for a total of 480,000.

Digital photography commonly uses much higher resolutions than computer screens with resolutions in the millions of pixels (megapixels). A camera with a resolution of 2048 x 1536 has a total resolution of 3.1 megapixels. Each pixel is represented by a number. The size of that number decides the colours scale that can be represented. For instance, black-and-white pictures can be represented with pixels which are just eight bits in length.

Colour must be represented with larger numbers. 16 bits per pixel, for instance, is necessary to have a colour scale of 65,536 different shades. 24 bits per pixel can represent more than 16 million different colours. Most digital cameras use 24 bits per pixel, however some professional equipment has a colour resolution of up to 48 bits per pixel for more than 280 billion different shades.

Choosing a sufficient pixel resolution depends a lot on the size of the photographs you want to print. Remember that the number of pixels in an image does not change, so pictures with larger dimensions will have fewer pixels per inch which results in a loss of detail if the picture size becomes too big.

Pictures printed at 200 pixels per inch are slightly less sharp but still quite acceptable for many purposes. At this resolution, you can get pictures up to 8.7″ x 5.8″ from a two megapixel camera, and 12.2″ x 8.2″ from a four megapixel camera.

Photo labs usually print pictures at 300 pixels per inch.The maximum print from a two megapixel camera at 300 pixels per inch is 5.8″ x 3.8″ — less than the standard 4″ x 6″. A camera with four megapixels can print pictures to a maximum size of 8.2″ x 5.4″ at 300 pixels per inch.

Digital Photography – Colour Balancing

The human eye can easily adapt to different light conditions so that objects maintain their ‘true’ colour.

In fact, each type of light amplifies a certain colour in the spectrum. What we consider to be ‘white’ light only occurs during the noon hours of a clear day. Sunlight in the early evening or late afternoon gives everything a reddish tint, and cloudy days bring out the blue end of the spectrum.

Each type of artificial light also has a particular colour cast. Incandescent lighting is yellowish and fluorescent lighting can be either blue or green.

All of these different lighting conditions affect the colour balance in photographs.

Most digital cameras allow you to adjust the colour balance for different types of light. This can be done manually or automatically, although the automatic settings can produce uneven results from one picture to another.

Manual settings can be done by selecting a preset such as ‘sunlight’ or ‘cloudy’, but these settings can be fine-tuned to match very specific lighting conditions.

Colour balance is achieved by adjusting the camera so that ‘white’ is truly ‘white’. Once the camera is set to correctly reproduce white, the other colours should appear to be their natural shade. This can be quickly checked by looking through the viewfinder of your digital camera. Holding up a piece of white paper in front of the camera will allow you to see whether it is the correct shade or not.

Some cameras can be set this way — place a sheet of white paper in front of the viewfinder and select ‘Auto Correct’.

Remember that the presets are general guidelines and may not be suitable for every type of lighting condition. If your camera has a setting for florescent lights, for example, it may still require further tweaking to get the correct colour balance.

Although it is best to try to get the proper colour balance when you are taking photographs, the colour of an image can also be adjusted using software. This should not be thought of as an alternative to proper colour balancing, but it can be used to good effect on some digital images.

Some computer software can automatically adjust colour as well as brightness and contrast. Start out with these ‘auto’ settings — sometimes the results can be surprisingly good.

This knowledge of how colours interact allows you to correct improper colour balances. For example, if an image is too red, adding some cyan (the opposite of red) can help to naturalize the colour.

Software can also be used to adjust colour intensity. Subtle use of imaging software can help to turn good photographs into great photographs.

Lenses for Digital Cameras

The lens is one of the components in digital cameras that play a big part in image quality. Get the best you can afford — good quality lenses are essential for getting the most out of digital photography.

Lenses are available in various focal lengths which decide field of view and depth of focus. As they become longer they can focus on smaller areas but require more precise focusing to obtain a sharp image. Longer lenses are also more susceptible to movement and will likely blur images if the camera is moved during a shot.

Long lenses are sometimes called telephoto lenses. Because of their reduced field of view, the images shot with telephoto lenses are magnified compared with shorter lenses. Similarly, shorter lenses give a wider field of view, so very short lenses are called wide-angle lenses.

A 50mm lens is considered normal for traditional 35mm cameras but digital image sensors are much smaller than a frame of 35mm film, so shorter lenses on digital cameras will capture the same field of view as the 50mm lens on a 35mm camera. The specifications of a digital camera lens will often include a reference to how the focal length compares to a 35mm camera.

Almost every digital camera has an optical zoom function that changes the focal length of the lens. They are rated as a multiplier – a 3X zoom will enlarge or reduce an image by 3 times from the longest to the shortest setting.

Some cameras are also equipped with a digital zoom. These work by cropping the image digitally and then spreading the result over all the photosites on the image sensor. This is inferior to optical zoom and should not be used. Better results can be obtained by editing the photo using computer software.

Most digital cameras in the mid-range and better have the ability to add lens converters. These give you more options for digital photography by allowing you to attach various types of lenses and filters.

In addition, many digital cameras can accept lenses made for film cameras. Because of the difference in size between film and image sensors, however, these lenses do not produce the same results as with film cameras. A telephoto lens designed for film will have a larger magnifying effect, and a wide angle lens will have less effect on a digital camera.

Lenses are quite expensive. They should be kept in cases and covered with caps when not in use. Most lenses come with caps but you may have to buy extras in case they are lost. They are widely available and fairly inexpensive.

Lens Hoods

Lens hoods are useful for controlling the amount of light entering the lens. They result in images that have less contrast – useful for some outdoor situations.

Lens Cleaning Kits

Lens cleaning kits are available but should be used as infrequently as possible. Avoid touching the lens with your fingers as the oils in your skin can cause permanent damage to the lens coating. Wipe fingerprints with a soft cloth but first remove dust particles with a blower. Larger dust can be removed with a soft brush.