Camera Lenses

All cameras - digital or otherwise - operate under the same general principals: capturing and preserving light as a way to create an image. Of course this is an oversimplification of the mechanisms responsible for the creation of a photograph and yet this idea is ultimately the core premise of photographic technology. Light is captured via one or another type of photosensitive material - in the case of digital cameras this is the camera sensor. Because this material reacts to light, if it is exposed to the outside world where light bounces off different objects in every direction the sensor will become overloaded and produce only a bright mass. However if light can be focussed and directed in one direction directly on to the sensor then all of a sudden the picture is able to form.

How a Camera Lens Works

Ultimately when a photograph is taken it is not actually recording the object which is represented but rather is a capture of the light which has reflected off of said object. Because light will be reflected in many different directions off of an object (unless it is perfectly smooth) the light that reaches the sensor will be scattered and fuzzy.

When it comes to photography and lens technology the important thing to understand about light is that travels as slightly different speeds through different materials. As it changes speed it will also change direction slightly. This property of light is what allows a lens to focus light into a directional beam. The curved shape of the lens focuses light on to a single point, no matter which direction the light is coming from. This allows light to be focussed directly onto a camera sensor or other photosensitive material.

Why Lenses are Important

This focusing process is of the utmost importance to the successful capture of an image. Focusing the light onto the sensor allows the image to be captured crisply and intelligibly. Without being able to focus light cameras would be unable to form images that were recognizable to humans. The focussed light allows different parts of the sensor material to be exposed to different levels and color values of light which allows a coherent image to be formed.

Different Types of Lens

Many digital cameras - specifically ultra compact, compact and medium format cameras - have a fixed lens. This means that you pretty much get whatever lens comes with your camera. These lenses tend to be small and simple and while they may be limiting to an advanced photographer they are perfectly acceptable for many applications.

Where lenses become even more important is in the world of Digital Single Lens Reflex (DSLR) cameras. These larger format cameras have much more powerful sensors and more importantly the ability to use many different types of lenses. The different lenses have radically different effects on the quality of the image and it is essential for DSLR photographers to develop and understanding of different lenses. There are many different styles and variations but some of the most common lenses include wide angle lenses, telephoto or zoom lenses and macro lenses.

Wide angle lenses have a long depth of field and are designed to gather light from a wide field of view. These lenses are excellent for taking big pictures such as landscape or architectural shots. Because they are so wide and cover such a large area they are less suitable for portraits or other shots with a closer focus.

Telephoto or zoom lenses are have a very long focal length and this results in their being appropriate for taking shots of very distant subjects. Telephoto lenses are often used by nature photographers or sports photographers when a subject can not always be approached directly and must be imaged from a distance.

Macro lenses have a very short focal length and as such are only useful for taking pictures of small things up close. While this may seem limiting the world of macro photography is very diverse and beautiful. If you have any doubt of the amazing images which can be taken with a macro lens check out this gallery of 25 beautiful macro photography shots.

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