The Student Room Group

What does the lens millimeter mean on DSLR's?

For example Canon 1000D comes with an 18-55mm lens for the cheapest package. What does the millimeter range mean?
Reply 1
http://en.wikipedia.org/wiki/Focal_length

There's a bit on focal lengths in photography there.

Remember when you're talking about lenses going on your camera there's a crop factor of 1.6 so the 18-55mm is effectively a 29-88mm lens in real money.
Reply 2
Original post by R. Murray
http://en.wikipedia.org/wiki/Focal_length

There's a bit on focal lengths in photography there.

Remember when you're talking about lenses going on your camera there's a crop factor of 1.6 so the 18-55mm is effectively a 29-88mm lens in real money.


I feel stupid but still don't get it! Could you explain it to me in basic terms of photography?
Reply 3
Original post by RosieRayner
I feel stupid but still don't get it! Could you explain it to me in basic terms of photography?


Basically the bigger the number, the more zoom you get - e.g. an object shot with the 18mm lens will appear smaller than the same object shot at the same distance with a 55mm lens.

It's not a huge issue, I've been using an SLR for a few years and still can't explain it very well. It's more important to know how images shot through lenses of different focal lengths will appear - e.g. wide angle lenses have more depth of field than a telephoto lens.
Reply 4
Reply 5
Original post by synergy1


Ahhh, thank you very much! This and the above made it all clear. :smile:

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