[n00b question] fast lens

[Marill]

When people say fast lens, what speed are they referring to?

i read wikipedia it says the lens fast is referring to that it can support a much faster shutter speed?

so it's not actually anything about the lens is fast, rather that the lens can support a faster shutter speed?

 

[chikon]

I think it means the lens can open to a larger aperture to allow more light in so that you can have a faster shutter speed for the same amount of exposure

 

[Marill]

I think it means the lens can open to a larger aperture to allow more light in so that you can have a faster shutter speed for the same amount of exposure

ok, so the speed actually does not refer to the lens itself, but rather refer to the speed of the shutter on the camera body, when using this lens.

 

[xonix]

"Fast" is not limited to just the lens or camera body itself. Read the below link to get a better understanding of the relationship of aperture / shutter / exposure.

http://www.photographyblogger.net/a-simple-exposure-guide-aperture-shutter-speed-iso/

And a cheat sheet to get a basic idea of what you get playing with these 3 factors: