What is the relationship betweenthe F-stops and the shutter speed?

Question

When I am shooting film, I get confised about finding the the right relationship between the f-stop and the shutter speed based on the light sensor. How would I find the optimal setting?

You guys are amazing here, a lot of VERY good answers from experience and interesting analogies. I honestly can't thank you all enough. I don't find voting necessary so i will leave it up for grabs. Once again, thank you for the time you took to answer my question.

Answer 1

The basic relationship of f-stop and shutter speed is in controlling how much light gets to the film (or digital sensor in digicams).

The Aperture f-stop sets how wide the lens is open, and the Shutter Speed sets how long it is open.

Correct exposure comes from a balance of f-stop and Speed. As the f-stop goes down (lens opens wider), the Speed have to increase to keep too much light from getting in. And vice-versa.

There is no one optimum setting for all situations. It depends on the shooting situation. Lighting is a major factor. You have to learn what works best in each different situation.

Other goals for the shot may influence your choices. For example, if you want to capture a fast moving object, you need a higher shutter speed. That will require a lower f-stop to get enough light.

If you want a large Depth of Field to get much of the shot in focus, you will need a higher f-stop. That will require a lower shutter speed to get enough light.

Some cameras can partially automate the process with Priority modes. Then you choose either speed or f-stop (depending on your goals), and the camera sets the other parameter to get a good exposure.

If you are using only manual mode, you will have to learn to analyze each situation, then set the appropriate f-stop and speed. There are light meters and reference tables (or automatic camera modes) that can help.

Good Luck

Answer 2

There are a lot of good answers already, but maybe I can put it very simply.

BOTH settings control how much light enters your camera. Once you find ANY technically correct setting with your meter, the relationship between f-stops and shutter speed is direct and linear. If you open the lens up one full stop (go to a lower number) and go to a faster shutter speed (go to a higher number), the amount of light hitting the film or sensor will be the same. You are letting in twice as much light for half the amount of time, so exactly the same amount of light (photons) hit the film or sensor.

The optimal setting would depend on whether you want to stop action or control the zone of focus more.

Bigger aperture openings (smaller f/stop numbers) will give you more control over exactly what is in focus and what is not while smaller aperture openings (bigger f/stop numbers) will make most or all of the photo in focus.

Faster shutter speeds (bigger numbers) will stop action better and slower shutter speeds (smaller numbers) will not stop action so much.

Here's an interesting point of view about determining exposure.

http://www.kenrockwell.com/tech/modern-exposure.htm

Answer 3

Remember the sweet 16 rule. For daylight, the normal exposure is f16 when the film ISO is the same as shutter speed. If you use ISO 100 film, and set the shutter for 1/100 second, then the fstop should be close to f16. If not then something odd is going on.

Film has reciprocity, so that opening the shutter will require a faster exposure to compensate, each stop doubles the speed.

If your light sensor is on the camera, it will either read the shutter speed for the fstop you have preset, or if you preset the shutter speed, then it read the fstop. Some cameras allow either mode of operation, depending on which is more important to the subject.

If you are using a meter not coupled to the camera, then you have to set the ISO of the film speed, and then the dial will give you suggested combinations of fstop/shutter based on reciprocity. Pick any that works for you.

Answer 4

I haven't used my water bucket analogy in a while, so here goes...

Imagine your picture you are filling with light is a bucket that you want to fill with water. That is your exposure. You have a hose pipe, (the aperture) and a faucet, (the shutter.) The water is the light.

If you have a large diameter hose, the water rushes in, so you can turn on the faucet for a short amount of time. If you have a small hose, the water trickles, so leave on the faucet a longer time. Either way will fill up your bucket.

So large aperture and fast shutter speed is the same **exposure** wise as small aperture and long shutter speed. Aperture also controls depth of field, so there are occasions when the aperture will control the shot, and other occasions when you will want the shutter speed to be in control. That is aperture priority or shutter priority. You choose one and the camera will choose the other for a correct exposure. Or shoot manually, where you choose it all!

Answer 5

OK , i teach this , in nut shell f-stop controls the amount of near to far that is in focus. the shutter controls the action or movement in the photograph,. the higher the number in f-stops the greater the amount of near to far in focus you will have, as far as shutter goes the higher the number the more of the action you will freeze , of coarse that will depend on the speed of the object you are trying to photograph. ex a person walking at a slow pace will need a slower shutter speed to capture the action , then say a running person. both of these things can be use to create interesting images , it is not always a good thing to freeze everything or have everything in focus. that is the great part about photography it is the most rewarding of the arts because it is a visual lie that can make a viewer believe a emotional truth. feel free to e-mail me if you have further questions.

Answer 6

F-stop determines how much you want to be in focus. So if you want everything from right in front of your lens to infinity to be in focus, use a large numbered (but small opening) F-stop. That can be confusing. I just try to remember that Ansel Adams was famous for using F64 (which most of us don't have on our lenses) and his images are all of wide sweeping vistas with everything in perfect focus.

The larger the number of F-stop, the less light you take in through your lens. So if you're in dark conditions, you have to use a small number F-stop (bigger opening).

If you want to compare this to your eye, stand in front of a mirror and switch the lights on and off. When the light is on, your pupil will be small and you can see further. When the light is off, your pupil will get larger and you can't see very far.

Shutter speed is more like how quickly you blink. When you blink slowly (or have a slow shutter speed), you take in more light. So in dark conditions, you need to slow down your shutter speed. But in bright conditions (noon on a no clouds day), you will get a lot of light, so you need a faster shutter speed.

Shutter speeds are measured in portions of seconds. So when your camera says 60, it really means 1/60 of a second. That's faster than 1 because 1 means 1 whole second. Really fast shutter speeds are closer to 1/2000 (but will show on the camera as 2000).

Faster shutter speeds are also needed to capture moving subjects without blur. Or you can slow down your shutter speed to intentionally blur motion (like to make waterfalls look cool or to have trailing lights from a car).

How do you combine the two. I determine which purpose my photo is serving. If I need to capture action, I set the shutter on a specific number and let the light meter select the right setting for the F-stop. If your camera doesn't have any automatic settings. then you at least have a meter and you only change the F-stop until the meter reads balanced.

More often, I am concerned about the focus depth of my images. I determine how much I want in focus, set it on a specific F-stop and then adjust the shutter speed until the meter reads balanced.

Answer 7

first off, it takes a lot of practice. your shutter speed and f stop setting depend on many factors... you're location, the light situation, ISO, etc.
say you are shooting on a sunny day outside and you want your foreground in focus and background out of focus.... you could set your ISO at 200, shutter speed at 1/500 of a second and your f stop at f8. (this is just for example, may vary.) the brighter light you have, the faster shutter speed you can use. f stop controls the aperture and focal area. If you use a higher number f stop like f22 you are actually closing more and allowing less light in but you will have a larger focal area. If you open the f stop to something like f5.6 you will have less focus.
another example... if you're shooting in the evening at ISO 400 (film speed) you would have to use a slower shutter speed to allow more light in. so you would use something like 1/30 or 1/15 of a second. anything lower would need a tripod. if you wanted everything in your viewfinder in focus you could set it a f16 or f 22. just remember that a higher number allows less light in so you may have to adjust your shutter speed accordingly.
i'll give you another quick example. i'm trying to make this make sense. say you take the same image but 2 different settings....
you set your shutter speed at 1/15 of a second and f stop at f22. this will give you full focus in the image.
then you change your f stop to f5.6- you will have to change your shutter speed to something more like 1/500 to even it out. this will give you focos only on the area you focus on, not the whole image.

basically it just takes practice. i hope this helps you. i know it can be a bit confusing at first.

Answer 8

im somewhat at a loss for words. i've got by no ability heard of a hundred twenty five velocity action picture. its basic as quickly as you recognize.the decrease the type f-provide up the greater mild hits the action picture. the better the type the less mild hits the action picture yet facilitates greater of the background to be in concentration. that's significant while taking photographs communities. iso is only the action picture velocity. i does no longer play around with it till you recognize your digicam. going to a techniques could make your pics unusable. finally shutter velocity is how lots you prefer to provide up flow. the better the type the less flow blur you get. yet that comes on the value of being too dark for indoors and evening paintings. i does by no ability bypass under a million/a hundred twenty five till you have IS on your lens. wish that facilitates. the least confusing ingredient to do is only use Av and bypass with the backside f-provide up your lens can guard. the digicam will regulate the shutter for you.