TMR812 wrote:
Could some please explain this whole "F" thing to me? It sounds like the lower the number, the bigger the aperature, and the faster the lens. Higher means smaller and slower. What do you mean by faster? Faster at what? Why is a larger aperature better?
I know, sooooo many questions from such a novice.... Perhaps someone could point me to a good reference that explains this.
Every basic photography class covers the basics of the camera on Day One. I recommend you find a basic class at your local community college or adult education center.
Lenses have an aperture (opening) where the light comes through it. Lenses with really big apertures let more light through, so they are more sensitive and can be used more in dim light. Big apertures mean low f-numbers. Lenses with small apertures don't let as much light through, but they are still useful in a general purpose way. Small apertures mean high f-numbers. As a general rule (with exceptions) the lower the f-number, the bigger the hunk of glass that it takes to produce it, and the more expensive and heavy the lens is.
The basic exposure is set up by the combination of ISO speed setting (sensitivity at the sensor), shutter speed (fractions of a second that the shutter is open), and lens aperture. If you are lucky enough to have a really big aperture lens (low f-number) then that allows you to shoot at quicker shutter speeds for a given ISO. So, in a way, the big aperture lens allows you to shoot faster, which is why the lens is called a fast lens, even though the lens itself doesn't really do anything about time.
---Bob Gross---