Photographers often ask, “What lens should I use?”
The usual answer in photography articles and YouTube videos is something like, “It depends on what you are photographing.” Then comes the familiar advice: use a wide-angle lens for landscapes, a telephoto lens for wildlife, and a normal lens for everyday photography.
That answer is easy to remember, but it does not teach anyone how to solve a photographic problem.
Several years ago, I wrote a post about camera settings. My point was that nobody can tell you the correct camera settings until they know what you are trying to accomplish.
The same is true when someone asks which lens to use.
The first question is not:
What lens should I use?
The first question is:
Why am I making this photograph?
What is the photograph about? What do I want the viewer to notice, feel, or understand?
Until I can answer that question, I cannot make an intelligent decision about a lens.
Lens Choice Is Not Just About Focal Length
Once I know why I am making the photograph, lens choice involves three tightly connected considerations:
- Field of View
- Depth of Field
- Focal length
They are not separate decisions. They work together.
Field of View determines what is included in the photograph and what is excluded. Do I need to show a person in the environment? Do I need to include a dramatic sky, foreground flowers, or a distant mountain? Or is the subject a bird, an animal, a face, or a small detail that should be isolated from everything around it?
Depth of Field determines how much of that view needs to appear sharp. Perhaps the photograph needs detail from the foreground to the horizon. Perhaps only the subject’s eyes need to be sharp, while the background becomes a soft suggestion. Perhaps a macro image needs enough depth to describe the entire flower—or perhaps one tiny detail is the story.
Focal length affects the Field of View available from a particular camera position. It also affects the practical depth-of-field choices available to me, especially because focal length, camera-to-subject distance, aperture, and background distance all work together.
I cannot choose one of these without affecting the others.
Camera Position Determines Perspective
There is another part of the problem that is often misunderstood.
A lens does not create perspective.
Camera position creates perspective.
Moving closer or farther away changes the apparent relationship between objects near and far. Moving lower can make a subject look more powerful. Moving higher can reveal patterns or show more of the surroundings. Moving left or right may separate a subject from a distracting background.
If I am free to move, I should first find the camera position that gives me the perspective I want. Then I choose the focal length that gives me the Field of View I need from that position.
For example, if I want a person to appear large against a distant mountain, I may need to stand far away and use a longer focal length. If I move close with a wide-angle lens, the person may become large in the frame, but the mountain will appear much smaller and farther away. The framing may be similar, but the photograph will not say the same thing.
Of course, I cannot always move. Wildlife, sports, a stage performance, a cliff edge, a fence, or a restricted location may determine where I must stand. In those situations, the available position may dictate the focal length I need.
Either way, choosing a lens is not as simple as saying, “wide-angle for landscapes” or “telephoto for wildlife.”
The Lens Helps Solve the Visual Problem
After I answer why I am making the photograph, I need to decide:
- What belongs in the frame?
- What should be excluded?
- How much of the scene needs to appear sharp?
- Where do I need to stand for the right perspective?
- What focal length gives me the necessary Field of View from that position?
Only then can I choose aperture for the Depth of Field I need.
Then I choose shutter speed for the amount of motion I want to show or stop. A fast shutter speed may freeze a bird in flight. A slower shutter speed may show motion in water or allow a moving subject to blur.
Aperture and shutter speed determine how much light reaches the sensor. They establish exposure.
ISO does not change exposure. ISO is a brightness setting. It changes how brightly the camera renders the signal that was captured. If I need f/8 for the Depth of Field and 1/1000 second to freeze a bird, I may raise ISO to obtain the brightness I want. But ISO did not put more light on the sensor.
A Better Question
Instead of asking, “What lens should I use?” try asking:
Why am I making this photograph?
Then ask:
- What Field of View supports that purpose?
- What Depth of Field supports that purpose?
- What focal length gives me both from the camera position available to me?
Photography is a problem-solving exercise.
The lens is not the answer. It is one of the tools used to create the answer.