A Short Course Book
Using Your Digital Camera
A Guide To Great Photographs

Normal Focal Lengths

 
It's hard to look at a photo and tell what focal-length lens was used to take it. However, objects in an image taken with a normal lens look normal in their spatial relationships.
 
 
It's hard to look at a photo and tell what focal-length lens was used to take it. However, objects in an image taken with a normal lens look normal in their spatial relationships.
A "normal lens" for a 35mm camera usually refers to a fixed focal length lens of 50mm or a zoom lens zoomed in a little from its widest angle. When using a lens of this focal length, the scene looks about the same as it does to the unaided eye. With a longer focal length, everything appears closer than it actually is. With a shorter focal length, everything looks farther away.

A normal-focal-length (50mm) lens isn't necessarily the one photographers normally to use. Many photographers prefer the wider angle of view and greater depth of field provided by a slightly shorter focal length.

SEE FOR YOURSELF
A lens is called normal because it captures a scene just as the human eye sees it. This seems to violate common sense because the eye's angle of view is much wider than any normal lens. However, you can demonstrate for yourself why a specific focal length is normal for your camera. While a passenger in a car, try zooming the lens or using a longer lens as you watch the traffic a head on the monitor. The longer focal length makes distant cars appear right on top of you; in reaction you might even try to put on your brakes and then discover the cars are nowhere near as close as you thought. With shorter focal lengths, cars look far ahead, even when relatively close. A normal focal-length makes the cars appear in the same distance relationship as you perceive them ordinarily.

Another demonstration is to take two photographs of greatly different size and tape them to a wall. Look at them one at a time on the camera's monitor with the lens zoomed to a normal focal-length a little above it's widest angle. Move close enough so each fills the monitor. You'll discover you are at the correct distance for viewing the prints. With a longer focal-length you would feel too far away, and with a shorter one too close.



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