Photography Basics: Aperture, Shutter speed and ISO

You have probably been photographing for a while now and want to learn more. You have used your camera on automatic mode mostly, but now you want to know more. More about the functions of your camera, but also more about how to use those functions creatively.

One of the first things one needs to know about photography is exposure. Exposure is about making your image brighter or darker. Today I will learn you how to control exposure with basic tools: aperture, shutter speed and ISO. As photography is all about capturing light, these three tools are all to be used to manipulate light.

First I will tell you some more about each and then I will explain how these can be used to make your images brighter or darker.

Aperture

Large aperture

The size of the aperture is measured in f-stops. A small aperture will be something like f22 of f16 where a large aperture can be f2 or f2.8. Each stop higher or lower either doubles of halves the amount of light. If you created an image at f8 and notice it is too dark. What do you do? Correct! You choose a larger aperture to let more light in.

Aperture also controls how much of your image is in focus. Photographers call this depth-of-field. The depth-of-field is how much of your image is in focus. For example. If you want to photograph a landscape with everything in focus, you will need to use a smaller aperture like f8, f11 or even f16. Do you want to photograph a flower and want only part of the flower in focus, you should use a larger aperture like f2.8 of f2. This way you will only have part of the flower in focus and the background will become blurry.

Below is a visual representation of the above.

Shutter speed

Shutter speed refers to the lenght the camera lets light in onto the sensor. This setting can be as high as 1/32.000 of a second and as low as minutes. Using a slower shutter speed will give a brighter image than a faster shutter speed. For example: A shutter speed of 1/60 of a second will give a brighter image than 1/125 of a second.

Normally for fast action scenes like sports, auto racing, etc. a faster shutter speed is needed to capture a sharp image without movement. A slow shutter speed would cause the image to be out of focus. For landscape images for example, shutter speed is not really important. The landscape is usually not moving that fast to cause problems with using slower shutter speeds.

Below is a visual representation of the above.

ISO

Do you know what ISO stands for? Hardly anyone knows. It stands for ‘International Standards Organisation’. The ISO setting on your camera controle the sensitivity of your camera setting. It is a software setting which controls how sensitive your camera is to light. This will also make your image brighter or darker. There is one major downside. Higher ISO causes noise in your image. However modern cameras are getting much better at making images at high ISO. Years ago the top cameras would make decent images at ISO 1600. Now entry level camera will still make great images at ISO 1600 or even ISO 3200.

If you want the highest possible quality image, you should choose the lowest possible setting on your camera. I would however advise to do some test shoots to figure out till what ISO you still find the images from your camera acceptable. You might be suprised how high ISO can be without negligable noise showing in your image.

Below is a visual representation of the above.

Now how does this all work together?

This is where it becomes something you will need to practice. Using all three tools: Aperture, shutter speed and ISO to make your images brigher or darker is difficult at first, but it will become second nature in time.

Before I advised you to test out till which ISO you still find the images from your camera acceptable. Each camera has an auto-ISO setting which enables you to select the maximum ISO your camera will use when creating an image. This way you will only need to worry about aperture and shutter speed. After that you need to think about what kind of image you want to take.

Do you want to take an image of someone running or race cars on a race track? Or do you want to create a portrait with a shallow depth-of-field? Or a landscape where the entire image is in focus from front to back? Answers to these questions will learn you what setting you need for your shutter speed or your aperture. It will be some expertimenting in getting your exposure correct, but you will get the hang of it with practice! We all did.

Now let’s finish off with a small quiz to check if you got it? Try to answers below questions. You can find the answers by clicking the box below the quiz after you finished. Good luck!

Quiz

1. Question 1: Will my image be more grainy with ISO6400 or with ISO200?
2. Question 2: I want a shallow Depth-of-Field in my image. Do I need to choose for f2 or f11?
3. Question 3: I want to capture a running person with sharp focus. Do I need to choose for 1/2 of 1/500 of a second?
4. Question 4: My image is too dark with the following settings: f8 / 1/250 / ISO3200. I need the current shutter speed to capture the image sharp. What do I do? I raise the ISO to ISO6400 or I change my aperture to f5.6?
5. Question 5: What setting will give a brighter image? f4 / 1/60 / ISO800 or f8 / 1/8 / ISO400

Some images in this article are snapshots from the Photo Cheat card for photographers. The cheat card is a summary of above. You can print it and take it with you when you are out shooting your images!

You can download it for free. Click here!