>>3777437Bellows allow the lens to move further away from the film. This allows it to focus closer.
Notice when you turn the focus ring in a lens to focus closer, how the front of the lens extends (i.e. some moving further away from the film)? This is how you focus closer. But the lens barrel only allows the lens to extend up to a point, and this defines the minimum focusing distance.
If you want to focus even closer, i.e. extend the lens even more, then you use the bellows. They act as a glorified, extended barrel.
I think you got things a bit backwards. Bellows don't magnify as in "zoom in".
When people talk about magnification with bellows they mean a different thing. When they say for instance 1:1 magnification it means the size of the object you're shooting will be the same as the size of the image on the film, i.e. say a 36mm lighter will fill your whole frame horizontally.
So "higher magnification" in that context means, the bellows will allow you to get/focus so much close to a small object, as to fill your whole frame (or more) with the object you're shooting.
They're for macro use, not for "zooming in".
Another option is "macro tubes", they act like the bellows but are rigid tubes instead, the disadvantage being they are more limited in how much you can move the lens around (and hence how much you can alter minimum focusing distance).
In general, bellows and tubes change the focusing range of your lens.
Say your lens has a focusing range of 0.5m-infinity. With bellows you can make it, say, 0.1m-2m, and with a "short" macro tube 0.25m-3m, while with a long macro tube 0.1m-2m.
Does it make sense?
