help with f-stop

mkedre · Jun 24, 2004

I'm new to learning and understanding photography (other than just point and shoot) and I'm having a hard time understanding f-stops. Can anyone explain it in an easy way? I'm in the market for an SLR and want to understand it so I know what I'm doing when I purchase. Thanks in advance!

Jovian · Jun 24, 2004

its really simple once you get the hang of it. The camera is a light tight box with a hole in it for the image to come thorough....the aperature is that hole. The f-stops control how much light comes through, along with the time it also controls depth of field...smaller aperatures(bigger number) creates more depth of field. Then to create your proper exposure you must find the right shutter speed based on your in camera meter, or a handheld light meter.

That's the simplified version. Try going to the library and getting a few books, they will go way more in depth than anyone can on here...they'll answer a lot of your questions...plus they usually have awesome little pictures to go along with it!

~Andrew~

Jovian · Jun 24, 2004

its really simple once you get the hang of it. The camera is a light tight box with a hole in it for the image to come thorough....the aperature is that hole. The f-stops control how much light comes through, along with the time it also controls depth of field...smaller aperatures(bigger number) creates more depth of field. Then to create your proper exposure you must find the right shutter speed based on your in camera meter, or a handheld light meter.

That's the simplified version. Try going to the library and getting a few books, they will go way more in depth than anyone can on here...they'll answer a lot of your questions...plus they usually have awesome little pictures to go along with it!

~Andrew~

ksmattfish · Jun 24, 2004

f/stop refers to the size of the aperture, or hole in the lens.

The most confusing thing for newbies is that a large f/stop number (such as f/16 or f/22) actually means a small aperture, while a small f/stop number (such as f/2 or less) means a large aperture.

The aperture is used to control how much light can reach the film. Obviously more light comes through a big hole than a small hole. The other control is shutter speed, which controls how long light is allowed to come through the aperture.

Aperture also affects depth of field (DOF). DOF is the area in your photograph that is acceptably sharp. A larger f/stop (smaller hole) has more DOF; a smaller f/stop (larger hole) has less DOF. Common examples of use would be:

f/2 (large aperture/less DOF) for portraits to simplify the background by blurring it out, leaving only the subject in focus.

f/22 (small aperture/greater DOF) for landscapes to make sure everything from the foreground to the background is in focus.

Lenses are listed stating their maximum aperture (lowest f/stop number). Typically a lens with a smaller f/stop number will be more expensive than a similar designed lens that doesn't open up as much. Check out the price difference between a f/4 or f/5.6 28mm-105mm zoom lens, and one that'll open up to f/2 or f/2.8, and you'll see what I mean.