I'm a relatively inexperienced SLR-user, I have a D50 which I'm ashamed to say has been mostly used on autopilot over the years. I'm now trying to learn the intricacies of shutter, aperture etc, and I was hoping someone here could explain a couple of things that don't make sense to me.
First of all, what decides how big of an aperture you can get - the lens or the camera body or both? I have a Nikkor 18-55 AF lens and the numbers on it say 1:3.5 - 5.6G. This is aperture, right? (Shouldn't the letter at the end read F then??)
Anyway, I tried adjusting the aperture in Manual mode - but the biggest aperture it would give me was F 4.5 (down to 29). Why will it not go to 3.5 as it says on the lens?
#1. "RE: Some newbie questions about aperture et.al." In response to Reply # 0
Land O Lakes, US
You're correct in that the number indicates the aperture. You 18-55 lens has a variable aperture and it can open up to f/3.5 at 18mm and will open to 5.6 at 55mm. When you saw f/4.0 you were probably at about 20mm or so. The number indicates the maximum (widest) aperture you can get at that focal length. And, you can adjust aperture from there down to probably f/22 or so.
#3. "RE: Some newbie questions about aperture et.al." In response to Reply # 2 Sat 06-Apr-13 03:41 AM by MEMcD
Welcome to Nikonians! Your 18-55mm f/3.5-5.6 is a variable aperture zoom meaning that the maximum aperture (smallest f/#) varies from f/3.5 at 18mm to f/5.6 at about 50mm to 55mm.
There are constant aperture zooms available like the 17-55mm f/2.8G ED IF AF-S DX (approx. $1300.00 US) that maintain the maximum aperture of f/2.8 throughout the entire zoom range (17mm-55mm).
The maximum aperture is limited by the diameter of the front lens element. The longer the focal length, the larger the front lens element must be to maintain the same aperture. The larger the front element the more expensive and heavier the lens.