Digital Photography Technology

The camera lens regarding optics in photography is extremely complicated and difficult to understand. There are many camera lens specifications that are required when designing a lens, and if a near perfect lens were made, it would be so heavy and long you would not want it. Cost is also a factor,

Computers have helped significantly in doing the calculations for the design of new lenses. Otherwise we would not have the vast array of lenses that we now have available to the average photographer.

A brief description of camera lens specifications.

A camera lens is made of multiple lenses or groups of lenses. They are all there for a reason: The amount and placement of the glass determines the f/ ratio, focusing, focal length, and correction for a variety of deficiencies.

Lens coatings are for the reduction of reflections. A single coating is good for light reflection reduction at a certain wavelength. Multi coatings will reduce reflections at several wavelengths. A lens shade is not as critical as it was in the days of non-coated lenses, but it is still a good practice to use one. It also gives certain amount of physical protection to the lens.

Resolution is how well the lens reproduces the image from the center of the picture to the outer edged. This will start to become obvious when making enlargements.

Flare and ghosting are caused by internal reflections of the lens. This is most prevalent when a light is shining directly into the lens. A good lens shade will eliminate some of these problems.

Distortion can also cause problems. Barrel distortion is taking a picture of something with vertical and horizontal lines; the line will be pulled to the edge of the picture. Pincushion distortion is when these same lines are pulled inward to toward the center of the picture.

Wide-angle distortion is very obvious in wide angle lenses when parallel lines are pulled together. There is nothing that can be done about it, except be careful about what you photograph.

There are other specifications that enter into the design of a lens, but are extremely complicated and not easily understood.

The end result is that quality costs.