hi, i'm new to photography, but I have questions about aperture, shutter speed , f-stop, and spot metering. I know aperture is the opening that lets light pass and smaller the aperture bigger the light pass the lower the depth field. shutter speed basically how quickly a picture is taken. I also know that both aperture and shutter speed makes exposure. But where I am very confused is the f-stop and spot metering f-stop has to do with aperture and zoom but i really don't know. also in my SLR I have a spot metering and I was reading it has to do with tone. i.e people wanting to take sunset photo take spot metering of a sky the move to the sun to take the picutre. my really question is what is f-stop and spot-metering and how do they affect exposure? thank you.