The settings: Aperture, Shutter Speed and Focus
Aperture: A hole that light passes across on its way through the lens. The photographer controls the size of it.
Shutter Speed: The amount of time that the sensor (or film) is exposed to light from the lens. The photographer controls these.
Focus: The distance at which the lens makes the subject look sharp and clear.The photographer controls this distance.
About all the buttons and dials on your camera are designed to control just these 3 things!
Modern cameras have automatic controls, which can be faster and easier than doing it all by yourself.
Nevertheless, no camera can tell how you want the photograph to look - studying how to work everything manually will allow you to be more creative!
Aperture: Half of "Exposure"
(The image is from shortcourses.com)
The term "Aperture" actually refers to the size of the aperture.
The photographer can change the size of the aperture with controls on the camera body.
Apertures are occasionally called "f-stops", and are commonly written with a script "f" in front. Look out - small numbers mean big apertures, and big numbers mean small apertures!
(For example, f2.8 is bigger than f16.) Each number in the series is considered to be 1 "stop" different than the last, allowing 1/2 as much light into the camera.
Some lenses "stop down" to different apertures than others. Zoom lenses usually have a lower aperture range than "prime" (non-zoom) lenses.
Low enlargement lenses commonly include bigger aperture settings, and high enlargement lenses usually include smaller ones.
The smaller you make the aperture, the less light can get through the lens.
You may have to balance a small aperture setting with a slower shutter speed to allow the right amount of light into the camera, and the other way around.
A smaller apertures will make the front and back leaves clearer; a larger one will make them blurrier.
Regardless of where you focus the lens, more of the photograph will appear sharp and clear if you use a smaller aperture.
To understand this for yourself, make a pin-hole in a piece of paper and look through it.
Focus your eye on something far away and hold a finger out in front of you.
Keep your eye focused, and take the paper away.
Notice how much blurrier your finger looks without the narrow hole!
This is why controlling the aperture size is important:
you are able to choose to make the whole picture sharp and clear, or to make most of it blurry and have only your focus point stand out.
Shutter Speed: The Other Half of "Exposure"
(The image is from shortcourses.com)
The "Shutter Speed" is the length of time that the shutter (a little metallic curtain) clicks open, letting light from the lens into the camera.
The photographer can change the shutter speed with a control on the camera body.
Shutter Speeds are given in seconds - typically in fractions of seconds.
The bigger the number the slower the shutter speed.
There are other shutter speeds too - from 1/8000s to many hours!
Each number in the series is considered to be 1 "stop" unlike the last, allowing 1/2 as much light into the camera.
E.g., 1/125s is two stops slower than 1/500s.
Cameras will usually just show you the bottom part of the shutter speed number:
For instance, 1/15s will be shown as 15. When the numbers get bigger than a second, they will add a quote: for example, 1s will be shown as 1".
The faster you make the shutter speed, the less light can come through the shutter.
You may have to balance a faster shutter speed with a wider aperture opening to let the right amount of light into the camera, and the other way around.
A faster shutter speeds will make the bird clearer; a slower one will make it even blurrier.
Fast shutter speeds "freeze" action, while slow shutter speeds show action as a blur.
For instance, if you are photographing a person riding a bicycle with a shutter speed of 1/250s, the rider in the photograph would appear to be almost still.
If you took the same photograph with a shutter speed of 1/15s, the rider would appear as a stripe across the photo.
1/8000s is fast enough to freeze the motion of plane propellers 2s (with the camera steady on a tripod) is long enough to make flowing water look smooth and silky.
Exposure: Aperture and Shutter Speed Combined
As you take a photograph with your camera, two important things happen:
the aperture snaps down to your chosen size, and the shutter clicks open for exactly as long as you told it to.
All in the blink of an eye!
The combination of the two is what's called an "exposure":
exposing the digital sensor (or film) to just the right amount of light to make the photograph appear not too light and not too dark.
Almost all cameras have built-in "light meters" that suggest appropriate exposures grounded on the brightness of the scene.
Exposures values are measured in stops (as if apertures and shutter speeds) relative to the suggested exposure.
By reading your light meter (look through the viewfinder) you are able to tell if the photograph you are about to make will be too bright (+), too dark (-), or just right.
You can then make adjustments to the aperture or shutter speed if you would like to.
You can get the same exposure by using different aperture and shutter speed combinations.
If you want the same results, you'll have to speed up or slow down the shutter speed by the same number of stops you widen or narrow the aperture by (and the other way around).
Remember the effects that different apertures and shutter speeds will create!
Your camera's light meter will change its suggested exposure based on the ISO setting of your digital sensor (or film).
The ISO setting changes the sensor's sensitivity to light, and is typically set to 100, 200, 400, 800, 1600 or 3200.
As usual, each higher ISO is one stop "faster" than the last, and requires half as much light to obtain as is exposure.
E.g., if your camera's light meter suggested "1/60s at f8" for ISO 100, it might suggest "1/125s at f8” or "1/60s at f11" for ISO 200.
Focus: Controlling Sharpness
Focusing nearer will sharpen the close leaf and blur the distant one, focusing further will do the contrary.
The focus control sets the distance at which objects will appear sharp and clear in the final photograph.
Setting the focus changes tiny distances between elements inside the lens, altering the way light passes through it.
Focus Is not measured in stops like other camera controls - it is just a distance, in either feet or meters.
The focus on new lenses can be set using a ring on the lens barrel.
A switch on the lens or the camera body sets the camera to "autofocus" (it finds the focus point automatically) or to "manual focus" (you finding the focus point by yourself).
Focusing Is not complicated, but it can be significant to do it carefully.
The focusing ranges of particular lenses vary, but most can focus from around 0.5m to infinity.
You will be able to easily tell where your lens is focused - everything at that distance will appear sharp and clear in your camera's view finder.
Some modern cameras also have "focus confirmation", a small light that flashes on in the viewfinder when correct focus is achieved, even when manually focusing.
Thank you,
Amir
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