[Photography] Focal length

focal_length

 

The focal length of a lens is the distance between its center and its principal focus. Since most of camera lenses are convex, which converge light, one easy way to determine the focal length is to take the lens and put it in front of a parallel beam (for example under the sun), while on the other side, place a paper and vary the distance between the paper and lens to the point when the image light is smallest (shown in the figure above).

 

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s