Wtf are these mm's?

[teotsi]

I am a complete beginner in photography, and only recently did I start learning about dslr cameras and lenses. My question is, what do these mm numbers clarify? For example, there are 18-55mm lenses, 100mm lenses and stuff like that... What do these numbers mean?

Thanks a lot [emoji4]

 

[EIngerson]

Milimeter. It's the focal length on your lens or the focal length you are shooting at.

 

[Stradawhovious]

In addition to that ^^^ the higher the number, the"closer" your subject will appear to you. For example, a 50mm lens on a full frame body will capture roughly the same amount of a scene that your naked eyes will. A wildlife shooter, wanting to get a much closer shot without having to get closer to the subject might grab a 300mm or 400mm lens.

18-55mm lens would refer to a "zoom" lens which has the ability to change from a focal length of 18mm to one of 55mm and all focal length's inbetween. A 50mm lens (or any other lens that only has one focal length) is referred to as a prime lens, where it is a fixed focal length, and you are unable to "zoom" with it.

This is the Reader's Digest version.

 

[Braineack]

because 18-55mm sounds better than 0.71-2.16in.

 

[teotsi]

So, if I get this right, focal length defines how close to the subject of the photo these lens can get you?

 

[Braineack]

Nikon | Imaging Products | NIKKOR Lens Simulator

 

[480sparky41 40]

So, if I get this right, focal length defines how close to the subject of the photo these lens can get you?

No. The distance between you and the subject will be a function of the lens' focus ability. All lenses have a minimum focus distance. Get closer than that, and you won't be able to focus.

Focal length will define the Field of View, given the number as well as the format you're shooting with.

 

[Didereaux]

I am a complete beginner in photography, and only recently did I start learning about dslr cameras and lenses. My question is, what do these mm numbers clarify? For example, there are 18-55mm lenses, 100mm lenses and stuff like that... What do these numbers mean?

Thanks a lot [emoji4]

Welcome to the rest of the world. Meter, centimeter, millimeter are metric units of length. with lens you have two mm lengths given usually. One is the over all focal length such as 50mm 70-200mm etc, the second one will be the diameter of the lens itself, such as 52mm, 77mm etc, this is the measurement that tells you what size circular filters will fit your lens..

 

[teotsi]

I am a complete beginner in photography, and only recently did I start learning about dslr cameras and lenses. My question is, what do these mm numbers clarify? For example, there are 18-55mm lenses, 100mm lenses and stuff like that... What do these numbers mean?

Thanks a lot [emoji4]

Welcome to the rest of the world. Meter, centimeter, millimeter are metric units of length. with lens you have two mm lengths given usually. One is the over all focal length such as 50mm 70-200mm etc, the second one will be the diameter of the lens itself, such as 52mm, 77mm etc, this is the measurement that tells you what size circular filters will fit your lens..

Heh, I am European, so I know everything about the metric system, as well as what mm means.


But what do these millimeters measure? My English are not that great, so an explanation for dummies would be great.
Edit: I Googled it and from what I saw, it is not a real life distance or something like that right? It calculates the distance between some components of the lens. So, the bigger the number, the biggest the zoom?

 

[pgriz]

Teotsi, these may be of interest to you:

Focal length - Wikipedia, the free encyclopedia
Aperture - Wikipedia, the free encyclopedia

 

[teotsi]

Teotsi, these may be of interest to you:

Focal length - Wikipedia, the free encyclopedia
Aperture - Wikipedia, the free encyclopedia

Thanks, finally got it [emoji4]