Photography Gear

Choosing Your Aperture

Aperture refers to how large the opening in your lens is.

Using larger apertures, e.g. f/2.8 allows more light to reach your sensor than smaller apertures, e.g., f/22. Apertures are often referred to as stops. If I stop my lens down from f/4 to f/2.8 doubles the amount of light that reaches my sensor. If I open my lens up from f/4 to f/8 halves the amount of light that reaches my sensor. Aperture has an impact of the technical quality of your image quality. Most lenses perform the best in the middle of their f/stop range, e.g., f/8. Specifically, as you “stop down” from f/2.8 to f/8, you should see a decrease in color fringing and an increase in sharpness. Aperture also has an impact on depth of field. Using larger apertures decreases your depth of field. Using a smaller aperture increases your depth of field. My approach to portrait photography is a great example of the impact that aperture can have on your photos. For environmental portraits, I tend to use a wider lens to get more of the background in focus. If I get real close to my subject, I can still blur the background a bit. But generally, I want to get more of the background in focus so I tend to take a few steps back from my subject and stop my lens down to f/2.8 or even f/5.6 to increase depth of field (and improve the technical image quality of my image). For close up or full body portraits, I tend to use a longer lens to focus on my subject and blur the background and shoot “wide open” to decrease depth of field. However, when shooting wide open, it’s critical to remember that if your subject is oriented at an angle to the camera lens, the eye that you are focused on may be in focus and the other subject’s eye (or other parts of the subject’s body) may be out of focus. If that’s an issue, you can stop down to f/2.8 or f/5.6.

Dylan Goldby does a good job discussing this topic in this video.

Choosing Your ISO

Choosing your ISO is also important, but less important than choosing your aperture or shutter speed in large part, because modern cameras offer much better low light or “high ISO” performance than they did in the past.

Raising your ISO, e.g., from ISO 100 to ISO 6400, will result in an increase in “noise” in your images, including color and monochromatic noise. This can result in a decrease in color accuracy and detail. This noise will show up more in darker areas of the image. It is true that images taken at a higher ISO have less dynamic range. This can result in less smooth transitions in highlight areas and less distinction between tones in darker areas. This can also limit your ability to manipulate the extreme highlights and shadows in post processing.

In general, I try to keep my ISO as low as possible to get “clean” images. However, I do raise it when it is dark and using a low ISO would force me to use a less than ideal shutter speed.

Dylan Goldby does a good job discussing this topic in this video.

Choosing Your Shutter Speed

Shutter speed refers to how long your shutter is open which naturally has an impact on how much light reaches your sensor. Faster shutter speeds, e.g., 1/1000th of a second, allow less light to reach your sensor. Slow shutter speeds, e.g., 1 second, allow more light to reach your sensor.

In general, when you are taking a picture of a stationary object, you should be able to get a sharp image by using a shutter speed = 1 divided the focal length of your lens, e.g., 1/60th of a second when using a 50mm lens. However, I double this to account for camera shake and other factors, including the movement of my subjects. When you are taking a picture of a moving object, you will need to use a faster shutter speed to get a sharp image, e.g., 1/1,000th of a second. Of course, you may want to use a slower shutter speed to express movement in your image. For example, as described in our landscape photography technique note, I often use a neutral density filter and a long exposures to turn the surface of the water into a glassy reflection or misty abstraction of what it actually looks like. Finally, I use two additional techniques for creative technique. The first is panning. Panning involves following a fast moving abstract with your camera. The section is moving my camera back and forth horizontally or vertically to create an abstract image, e.g., moving my camera vertically to create abstract images of trees and moving my camera back and forth horizontally to create an abstract image of water. 

Dylan Goldby does a good job discussing this topic in this video.