How and What Makes a Lens Work

Learn about Lenses and How They Work!

 

Understanding your camera lenses will allow you to become more creative with your digital photography. The key is to know which lens to choose for the task at hand. It can become a real tradeoff between lens speed, cost, image quality, the weight of the lens, the size of the lens, and the cost of the lens. Read on to get a better understanding of some important concepts pertaining to your focal length, image quality, aperture, zoom lens, and more.

Lens Elements

Most cameras except for the cheapest of cameras are made up of several lens elements. Each element directs the light ray path to accurately reconstruct the image on the digital sensor. The focus is to reduce aberrations by using the least number of expensive elements.

 

An optical aberration will occur when image points are not able to translate back to a single point once they pass through the lens. This causes your image to become blurred, it can result in a misalignment of the colors, or it can cause a contrast reduction. The lens can also cause a decrease the brightness of the image or the image distortion. All of these problems have the potential to occur with any lens.

 

The Focal Length Influence

The focal length of your lens will determine the angle of view and the degree of magnification for the image. A wide-angle lens has a short focal length. Where as a telephoto lens has a longer corresponding focal length.

 

The focal length determines your image perspective, but remember perspective changes the location relating to the subject. If you were to try to fill the frame using both a telephoto lens and a wide-angle lens it will change the perspective.

 

Perspective is an incredibly powerful tool for photography composition when used properly. It can also determine what focal length you choose. Keep this quick reference chart handy.

Lens – Focal Length                    Terminology                           Type of Photography

< 21mm                                   Extreme Wide Angle               Architecture

21mm – 35mm                        Wide Angle                             Landscape

35mm – 70mm                        Normal                                    Documentary and Street

70mm – 135mm                      Medium Telephoto                 Portraits

135mm – 300+mm                  Telephoto                                Bird, Sports, and Wildlife

 

Remember if you are using a telephoto lens there is a great likelihood of camera shake. Even a small amount of hand movement can wreck your picture.

 

A Zoom Lens Vs. A Prime Lens

 

With a zoom lens you are able to vary your focal length. Your lens will have a pre-defined range. With a zoom lens you have an option of many different compositions without changing the lens itself. The zoom lens is a powerful tool for photojournalists and with children’s photograph or pet photography.

 

Don’t make the mistake of thinking that because you have a zoom lens you never have to change the position. The zoom is just about increasing your options and your flexibility.

 

Lens Aperture

 

Finally, a quick look at the aperture of a lens. This is how much the lens can open or close to let more or less light in. Apertures are shown as f-stops. The larger the aperture the lower the f-stop, and the larger the aperture the faster the lens is. The great the aperture range the more options you have and the more artistic you can be. Sports photography requires a larger aperture.

 

This was just a brief look as some of the basics behind your camera lens to help you understand how your lens works.

Following Links for extra help and reviews:

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