# Thread: mm of lens and magnification

1. ## mm of lens and magnification

hey guys,

what mm of lens would give you a magnification of 1x?

?mm = 1X
?mm = 2X
.
.
.
.

Thanks,
Colin

2. X is counted by the total zoom divided by the widest zoom.

70-200mm = 200/70 = 2.8X, 1X = 70mm.
28-70mm == 70/28 = 2.5X, 1X = 28mm.
500mm = 500/500 = 1X, 1X = 500mm.

And so on.

In short, "X number of zoom", this phrase, is totally useless. The actual full range known is much better.

3. "Magnification
Lens magnification is calculated relative to the “normal“ 50mm lens. With a 50mm lens, a 6’ man will fill the frame at 8’. A 20mm lens is about half the focal length of the 50mm lens, and therefore has a magnification of 1/2. A 6’man will fill the frame at about half the distance, or at about 4’. A 400mm lens is about 8 times the focal length of the 50mm lens, and therefore has a magnification of 8. A 6’ man will fill the frame at about 64’.

The standard or “normal“ field of view of the human eye is about 40 degrees. This is about the horizontal field of view of the “normal“ 50mm lens. A 20mm lens is about half the focal length of the 50mm lens and has a field of view about twice as wide, or about 80 degrees. A 400mm lens is about 8 times the focal length of the 50mm lens and has a field of view about 1/8th its width, or about 5 degrees. "

Taken from http://www.shutterfreaks.com/Tips/LensSelection.html

4. THank you all=)

Colin

#### Posting Permissions

• You may not post new threads
• You may not post replies
• You may not post attachments
• You may not edit your posts
•