Let’s talk about the fundamental basics of photography, aperture, shutter speed, and ISO or known simply as the exposure triangle. These three building blocks of photography each have a vital role in controlling the exposure of an image. Plus, they each can have a creative effect on the outcome of the photo. Shooting on automatic mode your camera is deciding what aperture and shutter speed makes the best image at the set ISO. If you have not changed your camera settings it is most likely at either IS0 100 or 200. My goal is by the end of this article you will get out of automatic mode and start to make these decisions yourself either in aperture priority, shutter priority, or full manual mode.

Aperture

Let’s start with Aperture, the first element of the exposure triangle. Aperture controls the amount of light that will pass through the lens and onto the sensor, much like the iris in your eye. The iris is the part of the eye that controls how much light is let in and hits the retina. When there is less light the iris expands to allow our low light vision to get better. When there is more light the iris contracts down limiting the light to only the amount needed to see. Next time you’re in your bathroom try flipping the light on and off and examine how your iris changes to the changing light conditions.

The aperture is the equivalent to the iris. When you open the aperture up you are letting more light come through the lens and the image gets brighter. When the aperture is at the biggest it will go, this is called shooting wide open, usually this is f/1.8 or f/2.8. Conversely, when you stop it down you are letting less light come through the lens and the image will get darker. Usually, the lowest a lens will go is f/16 or f/22. Most people will avoid shooting at the extremes because most lenses will lose some sharpness at those f-stops.

I also told you that there is a Creative decision involved. Besides the amount of light, the aperture also controls the depth of field, DoF. The lower your f-stop the more in focus the scene will be. The higher the f-stop the smaller that field of sharpness will be. Landscape photographers will use f/8, f/11 or f/16 to ensure the vista is in focus from front to back. But if you wanted to isolate a subject like a portrait photographer, might you’ll want to have a higher f-stop like f/5.6, f/4, or f/2.8. This is also how you get that beautiful bokeh.

Shutter Speed

The second arm of the exposure triangle is Shutter Speed. The shutter speed controls how long the light will hit the sensor. The faster your shutter speed the shorter amount of time the sensor will be exposed to the light, thus the darker the resulting image. The slower your shutter speed the longer the sensor will be exposed to the light, thus the brighter the image.

Creatively, the shutter speed will either freeze time in its place or show movement. Think about a photographing a waterfall. If you wanted to capture the water in its place to emphasize the raw power you would use a fast shutter speed like 1/2000, but if you wanted the water to be smooth and ethereal then you would use a slower shutter speed like 4 seconds. Of course, this all depends on how fast or slow the water is flowing.

Finally, I should mention that there is a rule of thumb for hand holding. Your shutter speed should not be slower than the length of the lens you are using. So, for example, if you are using a 50mm lens then your shutter speed should be 1/50 at the lowest in order to prevent movement from your hand shaking. If you were using a 200mm then 1/200 would be the lowest. Again, there are exceptions to this rule but if you keep getting blurry photos when hand holding try going back to this.

ISO

Finally, the last piece of the exposure triangle is ISO. Generally, this is the last arm of the triangle that photographers will change because the consensus is that an ISO of 100 (or 200 if that’s where your camera starts) is the best viable option. The ISO acts as a multiplier. The higher the ISO the brighter an image will be. The lower the darker it will be. However, that brightens comes at a cost and will introduce more noise or grain into the image. Sometimes though there is no other way to get the image without raising the ISO so don’t be afraid to do it. A grainy/noisy image is better than no image. Plus, today most cameras will be able to handle any ISO up to 800 fine. Creatively you may want a little noise if you are going for a film look. However, I would just add that in post personally.

There you have it. Each arm or the Exposure Triangle explained in detail. I hope you got something from this article. If you have any questions, you can always reach out and I will be sure to answer them. Now I encourage you to switch over to aperture priority, shutter priority, or full manual mode and start making some of these decisions for yourself. Don’t forget to add a little bit of your creative spin on your scene. Happy shooting!