who knows how to use shutter speed and aperture on a camera?

Question

i am taking photography (intro to photography) and i have a project . well i have an rebel II/ rebel S II and i dont know how to use the shutter speed and making it into fraction ex: 1/15, 1/30 .. etc and the aperture as ex: f/11, f/8.. etc

Answer 1

The responses by jbahhh*, alick40 and wry humor** are fairly good. I like to use visual examples though so here goes.

Correct exposure is the product of light, ISO, f-stop and shutter speed. Change ISO and keep the f-stop constant and the shutter speed changes; change the shutter speed and the f-stop changes. Lets look at a hypothetical example on a bright sunny day using ISO 200 with our camera in Aperture Preferred Mode (we choose an aperture, the camera chooses the shutter speed):

f2 @ 1/1000
f2.8 @ 1/500
f4 @ 1/250
f5.6 @ 1/125
f8 @ 1/60
f11 @ 1/30
f16 @ 1/15

As less and less light is admitted by smaller and smaller f-stops the shutter stays open longer. All 7 of the above exposures are IDENTICAL.

The only differences we'll notice in our images is an improvement of sharpness and detail between f5.6 and f11 and an increase in Depth of Field (DOF) from f5.6 to f16.

Lenses perform best between f5.6 and f11 due to the shape of the opening in the diaphragm***. DOF increases between f5.6 and f16, especially with the wide angle lenses.

In our hypothetical example, if we used ISO 100 our shutter speeds would be one-half of the values shown, since ISO 100 is less sensitive to light and needs more time to react. If we used ISO 400 our shutter speeds would double since ISO 400 is more sensitive to light than ISO 200 and thus requires less time to react.

Thr results shown in our example would be the same in Shutter Preferred Mode (we set a shutter speed, the camera chooses an f-stop).

* jbahhh was trying to explain the Rule of 16. It states: "On a bright sunny day if you set the aperture to f16 and the shutter speed as a reciprocal of the film speed you will get correct exposure." So if we were using ISO 200 our shutter speed would be 1/250.

** wry humor said that f11 was the same with a 50mm lens as it is with a 300mm lens. While there are 300mm lenses with special glass and coatings to enhance performance, there will likely be a difference in meter readings since the light has to travel through more elements over a longer distance. This is of little importance when using an in-camera meter. We would only need to take it into consideration if we were using a hand-held light meter.

*** To understand why lenses perform better at certain f-stops we'll use this analogy:

Think of water (light) flowing unrestricted through a pipe (lens). Aimed at a target, some of the water will hit the center but most of it misses and randomly hits the area around the center. As we introduce a restriction (smaller f-stop) more of the water hits the center. With further restriction, even more water hits the center. Then things begin to change. At some point of restriction the water (light) becomes a mist (overspray) and scatters around the center.

Our image at f2 or f2.8 is degraded by "oversplash"; at f4 it improves and improves more at f5.6, f8 and f11. One of these f-stops will give us the best possible image quality. At some f-stop, perhaps f11, "overspray" begins to cause image degradation.

If you'd like to determine which f-stop is optimal on your lens or lenses you can perform a simple test. Take a sheet of newspaper and tape it to a wall lit uniformly (a sunlit wall, for example). Mount your camera on a tripod, set your ISO to 200, focus carefully (so you can read the newsprint) and make an exposure at each f-stop. (Use a to Post-It note to record the f-stop at each exposure.) Print the images and then examine them with a magnifying glass. Look for light fall-off from center to edge (edges will be darker) and the sharpness of the letters from the center to the edge. Note the f-stop that has the less light fall-off center to edge and the less loss of sharpness center to edge. That is the optimum f-stop for that lens. Repeat for each lens you own. This works equally well with zoom lenses.

Answer 2

Shutter speeds are given in seconds or a fractional portion of a second. Shutter speed is the amount of time the film recieves light from the scene. If the shutter speed dial is set to 60 then the shutter speed is 1/60 of a second; set to 500 shutter speed is 1/500 of a second. It is written this way to make the dial easier to read - the 1/xx is understood to be there. Some cameras are capable of shutter speeds of full seconds. As you turn the dial toword lower numbers you will notice that after 1, which is 1 second, the numbers will be in a different color and will incease value. At 2 of the new color the speed is 2 seconds, 5 is 5 seconds, etc. The f number refers to the aperture, or size of the opening that the light travels through. The f number is also referred to as the f-stop. The size of the opening is mathmatically derived. The actual size of the opening changes for different focal length lens because the light has to travel further on a long focal length lens than it does for a short focal length lens. (As light travels further from the source the weaker it gets due to dispersal). Thus f11 on a 50mm lens and f11 on a 300mm lens will allow the same amount of light to reach the film. As the f numer increases the amount of light reaching the lens decreases. So at f5.6 the film gets more light than it does at f11. So we sum up by saying that fstop determines how much light can get to the film and shutter speed determines how long that amount light is allowed to reach the film.

Answer 3

ISO (sensor sensitivity = how good the camera eye is in light) native is usually 100 ISO but some Olympus cams it is 200. Using the native ISO is best for lack of digital noise (akin to 'grain' in film days) Aperture widens (more light) as shutter speeds up (less time he light gets thru) For a given 'correct' exposure you therefore usually have several choices; on a sunny day outdoors f 11 at 125th of a second at ISO 100 may be the right balance. But you can choose f8 at 250th seconds, same ISO Or f4 at 1000th second, by cranking the ISO to 200 (which is usually not a noisy problem zone in modern cameras). The latter will give you a narrow depth of focus (nearby and in the distance will be fuzzy) The first will give almost everything in focus, but if the subject is moving quickly, it may be a bit blurred, especially if your hand holding technique is not perfect and the lens has a long focal length. So all these balances take a lot of trial and error and experience to balance for a given subject. Read a load of books, m8

Answer 4

You are asking the basic question on exposure, and the relationship between film speed, shutter speed and aperture.
First you need to decide what sort of photograph you are taking, and then set the best film speed.
Then depending on subject decide if shutter speed or aperture is more important.
Having set your selected aperture use the light meter in the camera to select the correct shutter speed.
All three things are interrelated and you need to understand each one to make your decisions.
In view of your question perhaps you should just select a preset programme and let the camera do the thinking for you.
If you are in the UK please email me if you need more help.

Answer 5

What do you mean you don't know?? They are kinda already set if you just click through them. I know on a sunny day, the sunny 16, you can do 1/100 @ f/16 and it is perfect. Then if you wanna change the settings just go equal distances in the opposite directions for the settings....like 1/80 @ f/18, I think that is correct. Can't think right now...but hopefully you get what I'm trying to say....

Answer 6

i know how to use these things, if you study hard you will learn them also

you are asking so many questions in one, so my answer is general

keep going on the course and you will learn these things, thats why you are there?

adjust appeture for control of depth, use shutter for control of movement - combine the two at the correct exposure, learn these things, and the camera controls to do these things

some good answers above with more details,

a