To be able to do any of the things that you wanted to do when you bought your digital camera, you need to understand exposure. While you are able to take some decent pictures right out of the box, once you have an understanding of exposure, you will find the pictures that you produce surpass the questionable title of ’snapshots’ and become photographs and memories[1].
Steps
Understand what “exposure of the image” is and how will it affect your photographs.
Exposure actually is an umbrella term that refers to two aspects of photography. What it is, is how we control the lightness and the darkness of the image.
The exposure is controlled by the camera’s light meter. Whether you control the light meter yourself or you let the camera do the light metering for you, it all sets the F-stop and shutter speed. The f stop can be considered like a fraction. F2.8 would be 1/2.8 versus F16 which would be 1/16. If you look at it like slices of a pie, you would get a lot more pie with 1/2.8 than you would with 1/16.
This can be very unnerving, but F-stops and shutter speeds on every picture to get the light right or the lightness and darkness and exposure.
A good way to understand it is to “Think of a bucket of water with a hole in the bottom. If you have a large hole in the bottom of the bucket (large aperture), water will drain out quickly (fast shutter speed). Conversely, for the same amount of water, if you have a small hole in the bottom of the bucket (small aperture), the water will drain out slowly (slow shutter speed).”[2]
Exposure or lightness and darkness in the picture is a combination of the F-stop, which is the size of the hole in the lens, and the shutter speed, which is the length of time that the shutters open. So, if you think about it, if you leave the shutter open longer, you’re getting more light to the film or more light to the digital sensor, so the picture gets brighter, or lighter. If you shorten the exposure (give less light to the film or to the digital sensor), the exposure gets darker. Longer shutter speed: more exposure, more light; shorter shutter speed: less exposure, less light.
Learn about your “f-stop”.[3]“F-stop” means fraction and the f-stop number is the fraction of the actual opening in the lens compared to the focal length of the lens. A way to understand the aperture is to
So, let’s say we have a lens with a focal length of 5 mm and we have an f-stop on the lens of 2. 5 divided by 2 is 2.5. The actual diameter where the light comes through the lens is 25 mm across. If we have an f-stop of 1, for example, on that 5 mm lens, 5 divided by 1 means there is a 5 mm hole that the light comes through. That’s what the f-stop number actually means.
Study your digital camera’s “manual exposure” mode.
In the manual mode we set “F” stop and shutter speed. If you really want to control the light, the exposure, how the picture works you need to learn to use manual. It’s not just for the propeller heads and the guys who still shoot film. Manual mode is still viable today even with digital because it’s really how you control the look and feel of your picture.
Understand why you would want to change the exposure.
- The aperture is really important to control the picture.
- The aperture lets in the light, and the light is the most important thing to your picture. Without light, we ain’t got a picture.
- So we set the aperture to control both the light and the amount of focus or depth of field.
- You set a wide opening, like f2 or 2.8, blur the background and have your subject razor sharp.
- You shoot a medium aperture, 5.6 or 8 so the subject is sharp and background is slightly out of focus but still recognizable.
- Shoot f smaller f-stops, like 11 and possibly smaller for a landscape picture when you want the flowers in the foreground, the river, and the mountains all in focus. Depending on your format, tiny apertures like f/16 and smaller will cause you to lose sharpness due to diffraction effects.
To many, the aperture is far more important to great pictures than the shutter speed, because it controls the look and feel of the picture.
Know why you want to change the ISO.
You change the ISO on your digital camera to control the camera’s sensitivity to light. In bright light we need the camera to be less sensitive, to give us a better quality picture. In low light where there’s less ambient light, we need more sensitivity in the camera. So we raise the ISO from 1 to 2 to 4 or maybe 8 if you have to, to get enough light in so the picture looks good. Now, what’s the payback? As you raise the ISO we get more noise or grain in the picture, and less color. So, you want to set the ISO as low as possible without having the ISO too low so we make blurry pictures.
Determine what ISO is required for your shot.
The ISO on your digital camera is just like it is on film. You used to buy the film by the kind of light you were using. Today you set the ISO on your camera depending on the light.
- How do you set it? On some cameras there’s a button right on the top of the camera that says ISO.
- You press the button, turn the dial, and change it.
- Some cameras you have to go into the menu and find the ISO setting. Click on the ISO setting and turn the dial and change it. That’s how you set the ISO on your digital camera.
Stop action by changing the shutter speed on your camera.
You change the shutter speed on your camera to affect the action-stopping ability. If you’re shooting a picture with your camera handheld, you will need a shutter speed of 125 or 250. Day to day activity can be handled at this speed.
- If you are shooting moving subjects, change your shutter speed to a shutter speed of 500 or a thousandth of a second to stop the moving subjects.
- If shooting pictures in low light, where you need more light to come in through the shutter, set the shutter speed to thirtieth or a fifteenth of a second. Now, when you do this, the action is going to blur. So, use thirty or fifteen when there’s low light or when you want the action to blur.
- Medium shutter speed: 125 or 250 for normal pictures.
- Fast shutter speed: 500 or 1000 for action.
- Thirtieth or a fifteenth of a second to blur action or under low light.
Learn how to change the shutter speed on your digital camera.
You might have the option of a dial, a button on your camera, or you may have to do it in-camera.
Always err on the side of underexposure.
Of course, it goes without saying that you want fantastic exposure, but if you can’t get it quite right, err on the side of underexposure (let your scene be a little dark). In a digital camera, when a picture is over-exposed, all of the information is lost and cannot be recovered. With underexposed pictures, you have some chance of recovering the picture through software.
Learn your camera’s “program mode”.
The exposure modes on your camera allow us to control how we set the light. The basic mode is the “p” mode (program mode) and what I tell people is if in doubt “pm” the camera. Which means use the p-mode; fully program, the camera sets the f-stop and shutter speed in determining the exposure. The advantage of p-mode is you don’t need to know anything. It’s just a little bit above the green auto or “idiot proof” mode. In p-mode, the camera sets stop and shutter speed and you as the photographer have no control of the action stopping ability or depth of field of the picture you create.
Get familiar with the “Aperture Priority” mode.
On your digital camera you have the choice of “A-mode” or aperture priority. In the aperture priority mode (it’s a way to determine the exposure); you the photographer picks the aperture or f-stop. The camera will choose the shutter speed for you. Aperture priority could be considered the more useful of the modes. So, you select the f-stop, whether it’s f2.8 to blur the background, f8 for medium focus, or f16 to make everything in focus.
Investigate your camera’s “shutter priority” mode. You want to at least have some familiarity with the shutter speed of your camera.
- On your camera, shutter priority can either be S or T mode depending on your camera.
- In shutter priority mode, you pick the shutter speed and the camera sets the F stop.
- The advantage of shutter speed is you set the number that’s most convenient or most comfortable to us.
- Then the camera will pick the other number, the F stop.
- And you can actually make pictures in shutter priority that are too light or too dark.
Related wikiHows
- How to Improve Your Photography Without Buying New Equipment
- How to Use Bounce Flash to Improve Your Photography
- How to Create an Inexpensive Photography Lightbox
- How to Take Better Photographs
- How to Take Digital Pictures of Pets
Sources and Citations
VideoJug Original source of information, shared with permission
Aperture and shutter speed explained
Aperture Basics
Article provided by wikiHow, a wiki how-to manual. Please edit this article and find author credits at the original wikiHow article on How to Understand Camera Exposure. All content on wikiHow can be shared under a Creative Commons license.
