Aperture for Prime Len

[dreamer_toons]

I'm thinking of buying a fixed focal len with a fixed aperture and in needs of some clarifications.

Say that the fixed aperture is 1.4, can I adjust the aperture to other values by means of my camera, 'A' mode or when I use the 'P' mode?

The reason why I am confused over this is becoz I was using my friend's 70-200mm f2.8. When I was using the 'P' mode, the aperture changed to f3.5 and some other values.

I thought that since it has a fixed aperture, it will be the same throughout. So what happens if I want to use my 'A' mode?

Appreciates your comments.

 

[catchlights]

that's maximum Aperture, not fixed, the widest aperture you able to use, the only FIXED aperture lens is mirror lens, which you can't change the lens aperture.

btw, A mode, aka aperture priority, you select a aperture to be use, the camera decide what speed to go with.

P mode, you let camera decide for you what is the best setting.

 

[adamadam]

In addition to what catchlight said, this thread could be helpful http://clubsnap.com/forums/showthread.php?t=340252