explain mm camera lens?

Question

i do not understand the mm specs

Answer 1

The "mm" spec tells you the focal length of the lens.

By itself, this doesn't mean much. But by comparing the mm spec, you get an idea what a camera with a particular lens would be good at.

Cameras with lenses below 40 mm are for "wide angle" pictures. The lower the mm number the wider the view through that lens. So a camera with a wide angle lens would be better for group portraits, or wide views of large objects (Grand Canyon), or whenever you need a wide view. The objects in these pics will look smaller, farther away than usual.

Cameras with lenses above 100 mm are for "telephoto" pictures. The higher the mm number the stronger the magnification or telescope effect. Cameras with these lenses are better for taking pictures of things farther away from you (a mountain) or for getting closeup of something you cannot get close to (a wild bird). The objects in these pics will look closer, bigger than normal.

Most digicams have "zoom" lenses where you see two numbers given for focal length, for example "35-105mm". This says the lens can change from 35mm (wide angle) all the way up to 105mm (telephoto). Since 35x3=105, this is called a "3x" zoom lens.

Using a camera with a 3x zoom lens allows you to choose between wide angle, and telephoto, and anything in between, for your pictures.

Have Fun!

Answer 2

It's the focal length of the lens. More specifically, it is the distance the lens is from the film plane when focused at infinity.

Longer lenses (higher mms) have more magnification, shorter lenses have a wider field of view.