The ability to use interchangeable lenses is undoubtedly the most important advantage of a DSLR. However there are many choices when it comes to choosing the right lens for a job; a fair understanding about camera lenses and their properties will definitely help to exercise more creative control over your digital photography.
Which lens is to be used to photograph a particular scene or object depend upon by many factors like focal length, angle of view, size and weight, lens speed, apertures, required image quality etc.
So in this section of our basic photography course, we will discuss the following characteristics of camera lenses.
- Focal Length
- Angle of View
- Lens Speed
- Depth of field
- Image quality and
- Lens sharpness
What is a camera lens?
A camera lens is in fact a collection of many different types of lenses and coupled with an aperture mechanism. Each element serves different functions and their combined role is to bend the light rays entering the lens in many different ways so as to focus them all precisely at the image sensor to form a sharp image of the scene in front of the lens.
Some of the lenses inside are grouped together;
Some are fixed in position
While others are floating elements (meaning their position change).
Why they move?
Elements inside the lens move to aid the camera in focusing, to zoom, or to assist in the optical image stabilization process.
Lens design is one complicated affair which involves solving many challenges. One of the major challenges is to make the lens sharper not only in the center but also across the entire width of the photograph including the extreme edges. The goal is to minimize aberrations, distortions, minimize flare etc. while still utilizing the fewest number of lens elements.
At first thought the function of a camera lens seems simple but it isn’t, lens design is one complicated affair which involves solving many challenges. One of the major challenges is to make the lens sharper not only in the center but also across the entire width of the photograph including the extreme edges. Matters get even more complicated when designing a zoom lens, as the lens has to focus precisely across various focal lengths.
The complexity of lens design is beyond the scope of this article so we will focus more on other aspects that really matter to us as photographers. The very first thing one should be aware of any lens is its focal length; so that is what we are going to discuss next.
NEXT: Focal Length