What Is a Field of View Calculator?
Field of view (FOV) is the angular extent of the scene a lens captures, measured in degrees. This calculator uses your focal length and sensor width and height to find the horizontal, vertical and diagonal angle of view — the same math used throughout photography optics to describe how "wide" or "tight" a lens sees.
Understanding field of view helps you choose the right lens for a shot, predict how much of a room or landscape will fit in the frame, and compare lenses across different sensor sizes.
How to Read Your Results
Horizontal FOV
This is the angle of view measured across the wide dimension of the sensor — how much of the scene fits left to right in your frame.
Vertical FOV
This is the angle of view measured across the short dimension of the sensor — how much of the scene fits top to bottom in your frame.
Diagonal FOV
This is the angle of view measured corner to corner across the sensor. It's the number most often quoted on lens spec sheets and boxes.
Real-World Example
Here's how field of view changes across common focal lengths on a full-frame (36mm x 24mm) sensor.
| Focal Length | Horizontal FOV | Vertical FOV | Diagonal FOV |
|---|---|---|---|
| 24mm | 73.7° | 53.1° | 84.1° |
| 50mm | 39.6° | 27.0° | 46.8° |
| 85mm | 23.9° | 16.1° | 28.6° |
| 200mm | 10.3° | 6.9° | 12.3° |
As focal length increases, the angle of view narrows sharply — a 200mm lens sees roughly a seventh of the horizontal angle a 24mm lens does on the same sensor.
Tips for Using Field of View
- Shorter focal lengths produce a wider field of view, capturing more of the scene.
- Longer focal lengths produce a narrower field of view, magnifying a smaller part of the scene.
- Crop-sensor cameras have a narrower field of view than full-frame cameras at the same focal length, because their smaller sensor only captures the center portion of the lens's image circle. This is often described using a crop factor (for example, 1.5x or 1.6x) — multiply the focal length by the crop factor to estimate its "full-frame equivalent" angle of view.
- Diagonal FOV is the figure most commonly printed on lens specifications, but horizontal and vertical FOV are usually more useful for framing a shot.
Frequently Asked Questions
What is crop factor?
Crop factor is the ratio between a full-frame (36mm x 24mm) sensor's diagonal and a smaller sensor's diagonal. A common APS-C crop factor is about 1.5x (1.6x for Canon APS-C), meaning a 50mm lens on that camera frames a scene similar to a 75mm lens on full frame.
Does field of view change with aperture?
No. Aperture controls how much light reaches the sensor and affects depth of field, but it does not change the angle of view. Field of view depends only on focal length and sensor size.
How does sensor size affect field of view?
For the same focal length, a smaller sensor captures a narrower field of view because it only records the center portion of the image the lens projects. That's why the same lens looks "more zoomed in" on a crop-sensor camera than on full frame.
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Last updated: August 2026 · Reviewed by: Simple Calculator Tools Editorial Team