the "f" number on zoom nikon lens

[Zilog]

With the Nikon/Nikkor 18-55mm f/3.5-5.6 I understand that the more you zoom the higher the f number becomes and the slower the lens becomes. But on the Nikon/Nikkor 17-55mm f/2.8 does the f number stay the same no matter what the zoom?

 

[Martyn...]

Yes if there is only one f number (on any lens not only Nikkors) it is described as being a constant f2.8

 

[Zilog]

Thanks Martyn...

 

[pete.rush]

With the Nikon/Nikkor 18-55mm f/3.5-5.6 I understand that the more you zoom the higher the f number becomes and the slower the lens becomes. But on the Nikon/Nikkor 17-55mm f/2.8 does the f number stay the same no matter what the zoom?

More info
http://www.cambridgeincolour.com/tutorials/camera-lenses.htm

 

[Martyn...]

More info
http://www.cambridgeincolour.com/tutorials/camera-lenses.htm

Cheers Pete, I have bookmarked that ....

 

[Zilog]

Thanks Pete that is a great link and has answered the next half dozen questions I was going to ask in one go