What focal length?

When shooting with any type of camera, but also a digital SLR camera, it is important to answer the question: What is the focal length?

This article will help you to understand the focal length along to show the importance of the focal length of the digital photography.

What is the focal length?

Here is the scientific explanation of the focal When parallel rays of light hit a target to converge infinitely to form a focal point. The focal length of the lens is the distance between the center of the focus of this lens. The focal length of the lens on the lens mount shown.

Types of lenses

Objectives are classified as wide-angle, standard or telephoto usually. The focal length of a lens determines the angle of view, so that wide-angle lenses, a smaller focal length, while a telephoto lens has a longer focal length.

Here is a list of definitions of the focal length is accepted in each category of the lens:

• Large wide-angle lens: less than 21mm
• 21-35mm: wide angle lens
• 35-70: Standard / lens
• 70-135mm: Standard Lens
• 135-300mm (or more): Tele

There are two types of lenses - the first (fixed) or Zoom. A main goal is a single focal length (50 mm for example), while a zoom lens covers a focal range (than 17-40 mm).

Focal length of the lens

The focal length of the set at the time of film photography and objectives refers to the focal length of a 35mm lens length of the camera. (Note, however, that 35 mm is the type of film used and not a focal length!) If you are lucky enough to have a professional full-frame DSLR is, the focal length is not affected.

However, if an average frame (APS-C) camera is used, the focus will be affected. Since the images of plant sensors are smaller than 35mm film strips, an increase that apply. The increase varies slightly between manufacturers, but the rule is x1.6. Canon used this increase, but uses Nikon and Olympus used x2 x1.5.

For example, in an image of Canon cutter a standard 50mm lens is a standard 80 mm telephoto. (50 mm multiplied by a factor of 1.6 to 80 mm.)

Most manufacturers now make lenses, so this extension work in cultures only format cameras. This is especially useful for large angles of things, where the expansion can convert these goals at the end of the series!