How to f-stops work in photography?

Question

I'm into photography but no one has ever really expalined to me how f-stops work. Can anyone help me?
ThanksQ

Answer 1

The f-stop controls the size of the opening for light to expose the film. The smaller the number(ie: f/4) the bigger the hole and the less amount of the picture is in focus. The larger the numer(ie; f/16) the smaller the hole and the larger the focal length. A way to remember is the bigger the number the more is in focus.



I had a teacher have me squint and notice that more of what I was looking at was in focus. The f numers are actually fractions so f/16 is a smaller hole in the aperture than f/4. That is why when you use a high number f stop a lower shutter speed is used.



I didn't understand it until I took a class when I was 19 and I had used cameras from the age of 10. I had also asked lots of people but it is not an easy concept( to understand or explain.) One exercise I had to do in class was line up several items and starting at the smallest f/stop and changing the speed to get the correct exposure I had to take a photograph at each f/stop .As the f stop number got higher the more of the photograph is in focused. If you do this and take notes while you do it, it might help.

Answer 2

Just remember the smaller the aperture, the sharper the picture.



It is the relationship of the focal lenght ( the point where the rays converge) and the actual diemeter of the aperture (f-stop).



A lens of 50mm and an opening of 25mm gives you an f:2

A lens of 100 mm with the same opening (25mm) will give you f:4, so to obtain the same f stop in this lens I have to open (the diafragm) to 50mm.



As you see in my example the same f-stop for different focal lenses, has different apertures



FOCAL LENGTH / DIAMETER = f-stop



the f-stop not always is 8; 11; 16; 22 etc. as conventional; they can be: 9; 10; 11; 12; 13; 14; 15; 16; 17; etc.;

Answer 3

It's measure of the size of a camera’s aperture. The higher the f-stop, the smaller the aperture. Its the ratio of the len's focal length to the size of the opening. For example a lens set at f-16 would be stopped down to 1/16th the size of the focal length.

Answer 4

Aperature or f-stop means lens opening. A small number = a large opening and vice versa. The smaller your lens opening (large f number) the greater your depth of field.

I highly reccommend you get a copy of the book "Photography" by John Upton and Barbara London. It is $$$ but well worth it. You can find it on Ebay for about $70.

Answer 5

f is the opening of the diaphragm (aperture). A higher number means a smaller opening, so if it's a photo taken outside when there's sunlight, you need a high F number. A lower number means a bigger opening, as for pictures taking indoors at night, with weak artificial light (you can use the flash and a medium aperture, too).



Combining shutter speed, lighing and aperture is an art.

Answer 6

f stop is the hole in the lens that regulates light coming in. the larger the number f11 the smaller the actual hole. so f2 would be a big hole, f11 smaall. if the hole is big, then your image will have a small depth of field...meaning the flower will be in focus but everything behind and in front won't be...if the number is large ie 11, the hole is small, and everything in the picture will be in focus (good for landscape)

Answer 7

The following website gives 'A Tedious Explanation of the f/stop'. Hope it helps.

Answer 8

f stop the the size of the iris in the lens....lets in more or less light

Answer 9

the f stops its work when you feel the numbers of it finished