When considering setting up a camera for time-lapse on a construction site, one of the first things to figure out is: “What will this camera actually capture?” This is where understanding your field of view (FOV) becomes essential and using simple but effective tools like the CamDo FOV calculator. It helps ensure your framing is right the first time, avoiding costly blind spots, unnecessary rework, or poor visuals.
In this guide, we’ll walk you through a beginner-friendly way to calculate, visualize, and plan your camera’s field of view, using simple tools and common-sense methods - before you ever climb a ladder
Step 1: What Is Field of View and Why It Matters
Field of View (or FOV) is the angle your camera can “see.” Think of it like a slice of pie radiating from your lens, the wider the angle, the more of the scene it captures from side to side.
This is especially important on construction sites, where you want to cover the full work area without missing key activities or overcomplicating things with multiple cameras. Knowing your FOV helps you position your camera once and capture exactly what you need, whether it’s slab pours, steel erection, or façade progress.
Step 2: Understand What Affects FOV
Two things directly affect how wide your camera sees:
-
Lens Focal Length: A shorter lens (e.g. 10mm or 16mm) gives a wider view. A longer lens (e.g. 50mm) gives a tighter, zoomed-in frame.
- Sensor Size: Cameras with larger sensors (like full-frame DSLRs) naturally capture more scene area than smaller ones (like GoPros or phones), even at the same focal length.
Here’s the cheat: GoPros with SolarUp generally give you a wide field of view (about 90–120° depending on the mode), which is why they’re so popular for construction time-lapse. DSLRs, on the other hand, give you more control over lenses but require a bit more planning. DataLens is 100°.
Step 3: Draw Your Field of View on a Site Plan
This is where it all comes together. The easiest way to figure out if your camera is in the right spot is to draw a triangle on your site map like the Scene Capture Triangle above.
Here’s how:
-
Mark the Camera Location
Place a dot where you plan to install the camera, on a rooftop, light pole, fence post, etc. -
Measure the Distance to Your Subject
Estimate or measure how far the camera will be from the area you want to capture (e.g. 60 feet from the foundation). -
Draw the Capture Triangle
Use a protractor or drawing tool to draw two lines radiating outward from the camera point. The angle between them should match your camera’s FOV, 90° is a common starting point. Where those lines hit your target distance, that’s the base of your triangle. -
Review What’s Covered
Everything inside that triangle is in frame. Anything outside? Not captured. You can now decide whether to reposition, raise the camera, or switch to a wider lens.
The Core Formula
CamDo has developed a simple FOV calculator here.
If you want to know the mathematical details of how it works, then read on!
The mathematical formula to estimate your Horizontal Field of View (HFOV) angle using math:
HFOV = 2 × arctangent ( sensor width ÷ (2 × focal length) )
If you're calculating how much ground coverage you'll get:
Scene Width = 2 × Distance to Subject × tan(HFOV ÷ 2)
Or to calculate the required distance from your subject to capture a known width:
Distance = (Scene Width ÷ 2) ÷ tan(HFOV ÷ 2)
Step 4: Use Real Examples to Guide Your Decisions
Let’s say you’re placing a DataLens (with about a 100° horizontal field of view) on a pole 50 ft away from your work zone. At that distance, you’ll capture roughly 100 ft of width. That’s usually enough to cover a foundation pour or staging area.
Here are some more examples:
Example 1: Determine the FOV Angle
Goal:You need to capture an 80 ft wide section from a distance of 100 ft.
Formula:
HFOV = 2 × arctan(80 ÷ (2 × 100)) = 2 × arctan(0.4) ≈ 43.6°
Result: You need a lens/camera setup that gives you ~44° horizontal FOV.
Example 2: Determine Scene Width from Known FOV
Goal:You’re using a GoPro (HFOV ≈ 90°) and mounting it 50 ft from the subject.
Formula:
Scene Width = 2 × 50 × tan(90° ÷ 2) = 2 × 50 × tan(45°) = 100 ft
Result:Your GoPro will capture a 100 ft wide section.
Bonus Tip: Test Before You Commit
Before you mount your camera permanently, do a quick dry run. Set it up temporarily, take a sample photo or a short time-lapse sequence, and evaluate the framing. This small step can save hours of rework in the future.
Key Definitions
- Field of View (FOV) – How wide your camera sees, usually measured in degrees.
- HFOV – Horizontal Field of View (left to right coverage).
- Focal Length – The number on your lens, in millimetres. Lower = wider.
- Sensor Size – The physical size of the camera’s imaging surface.
- Scene Width – The actual area captured at a certain distance.
Frequently Asked Questions
Q: What’s the easiest way to get started with FOV planning?
A: Use a wide-angle camera like a GoPro in Linear mode, mount it, take a test shot, and draw your coverage triangle on a site map.
Q: Do I need to memorize formulas?
A: Not at all. If you understand the basic triangle concept and use tools like the CamDo FOV calculator or rough estimation charts, you’ll get 90% of the value.
Q: What if I get the angle wrong?
A: If your camera misses the action, you can’t fix it later. That’s why planning, even basic planning, makes a huge difference for time-lapse.
Want to Learn More about the Cameras?
