FoV Manual

GeoLog Photography Tools | Version 1.0

Table of Contents

Introduction

What is the Field of View Calculator?

The Field of View (FoV) Calculator is a precision tool that shows exactly what area your camera will capture at a given distance. It calculates the physical dimensions (width, height, and diagonal) of the scene that will appear in your frame, helping you plan compositions, choose lenses, and position your camera.

Who Should Use This Tool?

  • Event Photographers: Determine if you can fit a group in your frame
  • Real Estate Photographers: Know exact room coverage from specific positions
  • Sports Photographers: Calculate reach of telephoto lenses
  • Product Photographers: Plan table size and backdrop dimensions
  • Landscape Photographers: Choose optimal focal length for scene composition
  • Portrait Photographers: Determine working distance for desired framing
  • Video Cinematographers: Plan camera placement and lens selection

Why Calculate Field of View?

Instead of trial and error, the FoV Calculator tells you precisely:

  • What will fit in your frame at any distance
  • What lens to use for desired coverage
  • Where to position your camera
  • How much room you need for a shoot
  • Whether you can fit a subject/scene in your frame

Understanding Field of View

The Basics

Field of View (FoV) is the extent of the scene your camera can capture, expressed as:

  • Angular FoV: The angle of coverage (in degrees)
  • Linear FoV: The physical dimensions at a specific distance (feet/inches or meters)

The Two Controls

Field of view is primarily controlled by two factors:

1. Focal Length

  • Shorter focal length (wide) = Wider field of view
    • 14mm = very wide (~114°)
    • 24mm = wide (~84°)
    • 35mm = moderate (~63°)
  • Longer focal length (telephoto) = Narrower field of view
    • 85mm = narrow (~28°)
    • 200mm = very narrow (~12°)
    • 600mm = extremely narrow (~4°)

2. Sensor Size

  • Larger sensor = Wider field of view at same focal length
  • Smaller sensor = Narrower field of view (crop factor effect)

Distance affects the linear dimensions but not the angular coverage.

Key Concepts

Horizontal FoV

  • Width of captured scene
  • Most important for landscape orientation
  • Determines if subjects fit side-to-side

Vertical FoV

  • Height of captured scene
  • Most important for portrait orientation
  • Determines if subjects fit top-to-bottom

Diagonal FoV

  • Corner-to-corner coverage
  • The “official” field of view spec
  • Often quoted in lens specifications

Aspect Ratio

  • Ratio of width to height
  • Typical values:
    • 3:2 (most DSLRs and mirrorless)
    • 4:3 (Micro Four Thirds, some phones)
    • 16:9 (video, some cameras)
  • Affects relative horizontal vs. vertical coverage

Angular vs. Linear FoV

Angular FoV (in degrees):

  • Independent of distance
  • A 50mm lens has ~40° horizontal FoV regardless of distance
  • Useful for comparing lenses

Linear FoV (in feet/meters):

  • Depends on distance
  • At 10 feet: 50mm captures ~7.3 feet wide
  • At 20 feet: 50mm captures ~14.6 feet wide (doubles)
  • Useful for planning actual shoots

The calculator provides both for complete information.

Getting Started

Accessing the Calculator

  1. Open GeoLog
  2. Tap the Menu button (three horizontal lines)
  3. Select FoV (scope/viewfinder icon)

First Time Setup

If you haven’t set up your gear yet:

  1. The calculator will load with a default Full Frame camera
  2. With a default 18-300mm zoom lens
  3. Set to 50mm focal length
  4. At 10 feet distance

You can use this to explore the calculator, but for accurate results you should add your actual camera and lenses.

Adding Your Gear

Before using the calculator effectively:

  1. Tap the Menu button
  2. Select Gear
  3. Add your camera body:
    • Camera name
    • Sensor type (Full Frame, APS-C, Micro Four Thirds, etc.)
    • Sensor dimensions are set automatically
  4. Add your lenses:
    • Lens name (e.g., “Canon 24-70mm f/2.8”)
    • Type: Prime or Zoom
    • Focal length(s)
  5. Return to FoV calculator

Your gear selections are saved and will persist between sessions.

Using the Calculator

The Interface

The FoV Calculator consists of three main sections:

Top Section: Input Controls

  • Camera/Lens selector
  • Focal length control (for zoom lenses)
  • Distance control

Middle Section: Visual Display

  • Schematic diagram showing FoV coverage
  • Camera position and viewing angle
  • Coverage area dimensions

Bottom Section: Results

  • Angular measurements (degrees)
  • Linear measurements (feet/inches or meters)
  • All three dimensions: horizontal, vertical, diagonal

Setting Camera and Lens

1. Tap the Camera/Lens Button

The button displays your current selection:

  • Camera name
  • Lens name
  • Focal length (if zoom)

2. Select Your Camera

A sheet appears showing all cameras in your gear list:

  • Tap your desired camera body
  • Camera specifications display below the name
  • Sensor dimensions affect FoV calculations

3. Select Your Lens

After selecting camera, choose from its lenses:

  • Prime lenses show fixed focal length
  • Zoom lenses show focal length range

4. For Zoom Lenses: Set Focal Length

A slider appears allowing you to set specific focal length:

  • Drag slider to desired focal length
  • Current value displays in real-time
  • Covers entire range of your zoom lens
  • FoV updates immediately as you adjust

Setting Distance

Distance determines the linear (physical) dimensions of your field of view.

Tap the Distance Button

A distance picker appears:

  • Imperial Mode: Feet and inches
  • Metric Mode: Meters

Imperial (Feet + Inches)

  • Two columns: Feet | Inches
  • Feet: 0-50 feet
  • Inches: 0-11 inches
  • Scroll each independently

Metric (Meters)

  • Single column in meters
  • Range: 0-15.24 meters (50 feet equivalent)
  • Two decimal precision

Infinity Mode

Toggle the ∞ switch for:

  • Distant subjects (landscapes, architecture)
  • Angular FoV only (linear dimensions are infinite)
  • Results show degrees of coverage

Measurement System

Change between Imperial and Metric in GeoLog Settings:

  1. Menu → Settings
  2. Measurement System
  3. Select Imperial or Metric

This affects:

  • Distance input
  • Linear FoV displays
  • Saved preferences

Reading the Results

Results Pages

The calculator provides three pages of information. Swipe left/right to navigate:

Page 1: Primary FoV Information Page 2: Detailed Measurements Page 3: Visual Schematic

Page 1: Primary FoV Information

Focal Length

  • Your selected focal length in millimeters
  • For prime lenses: fixed value
  • For zoom lenses: current zoom position

Distance

  • How far the subject/scene is from camera
  • Shows feet/inches (Imperial) or meters (Metric)
  • Shows ∞ if infinity mode is active

Horizontal Field of View

  • Angular: Coverage in degrees (left to right)
  • Linear: Physical width at specified distance
  • Most useful for landscape orientation

Vertical Field of View

  • Angular: Coverage in degrees (top to bottom)
  • Linear: Physical height at specified distance
  • Most useful for portrait orientation

Diagonal Field of View

  • Angular: Corner-to-corner coverage in degrees
  • Linear: Physical diagonal at specified distance
  • Often matches lens specification sheets

Understanding the Numbers

Example Reading 1: Portrait Session

Focal Length: 85mm
Distance: 10'0"

Horizontal FoV: 16.5° / 2'11"
Vertical FoV: 11.0° / 1'11"
Diagonal FoV: 19.8° / 3'6"

Interpretation:

  • Using an 85mm lens at 10 feet
  • Frame width is 2’11” (35 inches)
  • Frame height is 1’11” (23 inches)
  • Perfect for head-and-shoulders portrait
  • Subject needs to be 3 feet or less wide to fit

Example Reading 2: Real Estate Interior

Focal Length: 16mm
Distance: 12'0"

Horizontal FoV: 83.0° / 22'6"
Vertical FoV: 61.9° / 15'0"
Diagonal FoV: 96.7° / 27'5"

Interpretation:

  • Using ultra-wide 16mm lens at 12 feet
  • Can capture 22.5 feet of wall width
  • Can capture 15 feet of ceiling height
  • Ideal for room interiors
  • Captures nearly the entire room from one corner

Example Reading 3: Sports Photography

Focal Length: 400mm
Distance: 100'0"

Horizontal FoV: 3.5° / 6'1"
Vertical FoV: 2.3° / 4'1"
Diagonal FoV: 4.2° / 7'3"

Interpretation:

  • Using long telephoto 400mm at 100 feet
  • Frame width is only 6 feet
  • Frame height is only 4 feet
  • Very narrow coverage
  • Perfect for isolating individual player
  • Shows importance of focal length for sports

Visual Schematic

The schematic displays:

  • Camera position (left side)
  • Viewing angle (cone shape)
  • Field of view dimensions at distance
  • Horizontal span (width)
  • Vertical span (height)
  • Scale markings for reference

How to Read the Diagram:

  • Left: Camera lens (circle)
  • Lines: Edges of visible coverage
  • Right side: Shows captured area
  • Labels: Dimensions at your set distance

Angular vs. Linear Toggle

Some displays show both:

  • Degrees: Angular coverage (independent of distance)
  • Dimensions: Linear size at specific distance

Toggle between views or see both simultaneously depending on display mode.

My Gear Management

Why Add Your Gear?

The FoV Calculator needs accurate sensor dimensions because different sensor sizes capture different fields of view with the same lens:

  • Full Frame 50mm ≠ APS-C 50mm
  • Crop factor affects FoV
  • Calculator needs exact sensor dimensions

Adding a Camera

  1. Menu → Gear → Add Camera
  2. Enter Camera Details:
    • Camera Name: Any descriptive name (e.g., “Canon R5”, “Nikon Z7”, “Sony A7 IV”)
    • Capture Plane: Select sensor size from list
  3. Common Sensor Sizes:
    • Full Frame: 36×24mm (Canon EOS R, Nikon Z, Sony A7)
      • Standard reference sensor
    • APS-C Canon: 22.2×14.8mm (Canon 90D, R7)
      • 1.6x crop factor
    • APS-C Nikon/Sony: 23.5×15.6mm (Nikon Z50, Sony A6000)
      • 1.5x crop factor
    • Micro Four Thirds: 17.3×13mm (Olympus, Panasonic)
      • 2x crop factor
    • Medium Format: 43.8×32.9mm (Fujifilm GFX, Hasselblad)
      • 0.79x crop factor (wider than full frame)
    • 1-inch: 13.2×8.8mm (some premium compacts)
      • 2.7x crop factor
  4. Sensor dimensions auto-populate based on capture plane selection
  5. Tap Save

Adding Lenses to a Camera

  1. Select your camera in Gear list
  2. Tap “Add Lens”
  3. Choose Lens Type:

Prime Lens

  • Fixed focal length
  • Enter single value (e.g., 24mm, 50mm, 135mm)
  • Optionally include maximum aperture in name

Zoom Lens

  • Variable focal length
  • Enter range (e.g., 24-70mm, 70-200mm, 100-400mm)
  • Can use any focal length within range
  1. Enter Lens Name
    • Descriptive name helps identify lens
    • Examples:
      • “Canon RF 15-35mm f/2.8L”
      • “Nikon 200-500mm f/5.6 VR”
      • “Sony 16mm f/2.8 Fisheye”
  2. Tap Save

Managing Gear

Edit Camera:

  • Tap camera in list
  • Modify name or sensor type
  • Changes affect all FoV calculations

Delete Camera:

  • Swipe left on camera
  • Tap Delete
  • Warning: This deletes all lenses attached to this camera

Edit Lens:

  • Tap lens under camera
  • Modify name, type, or focal length
  • Changes apply immediately in FoV calculator

Delete Lens:

  • Swipe left on lens
  • Tap Delete

Crop Factor Reference

Understanding how sensor size affects FoV:

Full Frame (reference):

  • 50mm = 50mm (no crop)
  • 40° horizontal FoV

APS-C Canon (1.6x crop):

  • 50mm = 80mm equivalent FoV
  • 25° horizontal FoV (narrower)

APS-C Nikon/Sony (1.5x crop):

  • 50mm = 75mm equivalent FoV
  • 27° horizontal FoV (narrower)

Micro Four Thirds (2x crop):

  • 50mm = 100mm equivalent FoV
  • 20° horizontal FoV (much narrower)

Medium Format (0.79x crop):

  • 50mm = 40mm equivalent FoV
  • 50° horizontal FoV (wider)

The calculator automatically handles these differences based on your camera’s actual sensor size.

Practical Applications

Portrait Photography

Goal: Determine working distance for desired framing

Full Length Portrait:

  • Subject is 6 feet tall
  • Want 6-8 feet of frame height
  • Need headroom and foot room

Example Calculation:

Camera: Full Frame
Lens: 85mm

Try 15 feet distance:
Vertical FoV: 5'9" ✗ (too tight)

Try 20 feet distance:
Vertical FoV: 7'8" ✓ (perfect)

Result: Stand 20 feet from subject

Headshot:

  • Subject’s head/shoulders is ~18 inches tall
  • Want frame height of 24-30 inches

Example Calculation:

Camera: Full Frame
Lens: 85mm

Try 5 feet distance:
Vertical FoV: 2'2" ✓ (26 inches, perfect)

Result: Stand 5 feet from subject

Event Photography

Goal: Fit group in frame from limited space

Wedding Reception:

  • Table is 8 feet wide
  • Need to capture entire table
  • Room only allows 12 feet distance

Example Calculation:

Camera: Full Frame
Distance: 12'0"

Try 24mm lens:
Horizontal FoV: 13'3" ✓ (fits 8-foot table)

Try 35mm lens:
Horizontal FoV: 9'4" ✓ (fits with margin)

Try 50mm lens:
Horizontal FoV: 6'7" ✗ (too tight)

Result: Use 24mm or 35mm lens

Real Estate Photography

Goal: Determine if wide angle lens can capture entire room

Master Bedroom:

  • Room is 15×18 feet
  • Shooting from corner
  • Maximum distance: 21 feet (diagonal)

Example Calculation:

Camera: Full Frame
Lens: 16mm
Distance: 21'0"

Horizontal FoV: 39'3" ✓ (much wider than room)
Vertical FoV: 26'2" ✓ (captures floor to ceiling)

Result: 16mm lens more than adequate

Kitchen:

  • Room is 12×14 feet
  • Need to capture from doorway
  • Distance: 14 feet

Example Calculation:

Camera: Full Frame
Lens: 24mm
Distance: 14'0"

Horizontal FoV: 15'5" ✓ (captures 14-foot width)
Vertical FoV: 10'3" ✓ (captures ceiling)

Result: 24mm lens works perfectly

Sports Photography

Goal: Calculate telephoto reach for field coverage

Soccer Field:

  • Far goal is 120 yards (360 feet) away
  • Want to fill frame with goal (24 feet wide)

Example Calculation:

Camera: APS-C (Nikon)
Distance: 360'0"

Try 300mm lens:
Horizontal FoV: 21'7" ✓ (close to 24 feet)

Try 400mm lens:
Horizontal FoV: 16'3" ✗ (too tight)

Result: 300mm is ideal focal length

Product Photography

Goal: Plan table size and backdrop dimensions

Product Shoot:

  • Product is 12 inches wide
  • Want product to fill 60% of frame width
  • Using 100mm macro lens

Example Calculation:

Camera: Full Frame
Lens: 100mm

Frame width needed: 12" / 0.6 = 20"

Find distance that gives 20" width:
Try 3'0" distance:
Horizontal FoV: 13" ✗ (too small)

Try 4'0" distance:
Horizontal FoV: 17" ✗ (still too small)

Try 5'0" distance:
Horizontal FoV: 22" ✓ (close enough)

Result: Position camera 5 feet from product
Table needs: ~25" width minimum (for margins)

Landscape Photography

Goal: Choose lens for desired composition

Scene:

  • Want to include mountain range (6 miles wide)
  • At 10 miles distance
  • Which lens to use?

Example Calculation:

Camera: Full Frame
Distance: 52,800'0" (10 miles)

Try 24mm lens:
Horizontal FoV: 58,256' (11 miles) ✓ (fits)

Try 35mm lens:
Horizontal FoV: 40,834' (7.7 miles) ✓ (fits tighter)

Try 50mm lens:
Horizontal FoV: 28,933' (5.5 miles) ✗ (too tight)

Result: 24mm for expansive view, 35mm for tighter composition

Video Production

Goal: Plan camera placement for interview setup

Interview:

  • Subject framing: chest-and-up (36 inches tall)
  • Using 50mm lens (cinematic look)
  • How far from subject?

Example Calculation:

Camera: Full Frame (16:9 video mode)
Lens: 50mm

Target vertical FoV: 40-45 inches (margin for headroom)

Try 6'0" distance:
Vertical FoV: 35" ✗ (too tight)

Try 7'0" distance:
Vertical FoV: 41" ✓ (perfect)

Try 8'0" distance:
Vertical FoV: 47" ✓ (more margin)

Result: Position camera 7-8 feet from subject

Tips & Best Practices

Choosing the Right Lens

For Tight Spaces:

  • Use calculator to work backwards
  • Know your distance limitation
  • Input distance, see which lens gives needed coverage
  • Ultra-wide (14-24mm) usually required

For Distant Subjects:

  • Calculate how much reach you actually need
  • Don’t over-buy telephoto
  • A 300mm may be sufficient where you thought you needed 600mm
  • Calculator prevents expensive mistakes

For New Gear:

  • Before buying lens, use calculator with rental focal lengths
  • Verify it covers your typical shooting scenarios
  • Check multiple distances you commonly shoot
  • Ensure it meets your coverage needs

Understanding Working Distance

Too Close Problems:

  • Subject distortion (wide lenses)
  • Intimidating for subject (portraits)
  • Difficult to interact (events)
  • Lighting challenges

Too Far Problems:

  • Harder to direct subject
  • Need louder communication
  • More environmental distractions
  • Longer lenses required (cost, weight)

Sweet Spot:

  • Portraits: 6-12 feet (comfortable social distance)
  • Events: 10-20 feet (non-intrusive)
  • Products: 3-6 feet (depends on size)

Use calculator to find focal length that gives desired framing at comfortable working distance.

Planning Multi-Camera Setups

For events with multiple cameras:

  1. Calculate each camera’s coverage
    • Input distance from each camera position
    • Check horizontal and vertical FoV
    • Ensure no overlap or gaps
  2. Match focal lengths to positions
    • Close cameras: moderate focal lengths (35-50mm)
    • Mid-distance cameras: short telephoto (70-135mm)
    • Far cameras: telephoto (200-400mm)
  3. Verify subject coverage
    • Check that each camera fully frames subject
    • Account for subject movement
    • Add margin for safety

Example: Wedding Ceremony

Camera A (back center): 70mm at 50 feet
FoV: 12' wide (captures altar perfectly)

Camera B (side right): 50mm at 30 feet
FoV: 13' wide (captures processional)

Camera C (detail close): 24mm at 10 feet
FoV: 13' wide (ring exchange close-up)

Verifying Lens Specifications

Manufacturer specs often use diagonal FoV. Verify:

  1. Input lens focal length
  2. Check diagonal FoV result
  3. Compare to manufacturer specification
  4. Should match within 1-2 degrees

If significantly different:

  • Verify correct sensor size selected
  • Check if manufacturer lists full-frame equivalent
  • Some lenses have actual focal length variation

Room Planning

When scouting locations:

  1. Measure room dimensions
    • Width, length, height
    • Door positions
    • Obstructions
  2. Identify camera positions
    • Where can you physically place camera?
    • Measure distance to subject area
  3. Calculate required lens
    • Input measured distances
    • Find which lenses cover room adequately
    • Account for composition margins
  4. Plan backup positions
    • Calculate alternative camera positions
    • Note lens requirements for each
    • Have contingency plan

Perspective Planning

Field of view ≠ perspective:

  • FoV determines what fits in frame
  • Perspective determined by camera-to-subject distance

To maintain perspective while changing framing:

  • Keep distance constant
  • Change focal length to adjust framing
  • Subject proportions remain consistent

To change perspective:

  • Change distance
  • Adjust focal length to maintain framing
  • Subject proportions change

Use calculator to plan both framing and perspective.

Troubleshooting

Results Don’t Match Real World

Problem: Calculator says scene fits, but it doesn’t in actual photo

Possible Causes:

1. Incorrect Sensor Size Selected

  • Verify camera in your gear list has correct sensor
  • APS-C varies by manufacturer
  • Solution: Check camera specs, update gear

2. Incorrect Focal Length

  • Zoom lenses: slider not at intended position
  • Some lenses have focal length variance
  • Solution: Verify actual focal length used

3. Measured Distance Wrong

  • Distance should be from sensor plane to subject
  • Not from front of lens
  • Solution: Measure from camera body (sensor plane mark)

4. Subject Movement

  • Subject moved between measurement and shooting
  • Solution: Add safety margin to calculations

5. Lens Breathing

  • Some lenses change focal length when focusing
  • Calculator assumes constant focal length
  • Solution: Add 10% margin for macro/close focus

Can’t Fit Subject in Frame

Problem: Calculator shows subject should fit, but doesn’t

Solutions:

Option 1: Verify Distance

  • Re-measure actual distance
  • Use laser measure for accuracy
  • Account for any obstructions

Option 2: Use Wider Lens

  • Input current distance
  • Try shorter focal lengths
  • Find focal length with adequate coverage

Option 3: Increase Distance

  • If space allows, move farther back
  • Recalculate with new distance
  • Verify coverage improves

Option 4: Crop Format

  • Check if shooting in crop mode
  • Some cameras have APS-C crop in video mode
  • Verify actual sensor area being used

Calculations Seem Wrong for Wide Angles

Problem: Ultra-wide lenses (14mm, 16mm) show unrealistic coverage

Explanation:

The calculator uses rectilinear projection (straight lines stay straight). Real ultra-wide lenses may have:

  • Slight barrel distortion
  • Actual coverage slightly less than calculated
  • Edge softness reducing effective coverage

Solution:

  • Add 5-10% margin for ultra-wide lenses
  • Test actual lens coverage
  • Note real-world results differ slightly from theory

Infinity Mode Shows Only Angles

Problem: When ∞ is enabled, linear dimensions disappear

Explanation:

This is correct behavior:

  • At infinite distance, linear FoV is infinite
  • Only angular coverage is meaningful
  • Shows degrees of coverage only

Use Cases for Infinity Mode:

  • Comparing lens angular coverage
  • Astrophotography (stars are at infinity)
  • Distant landscapes
  • Architectural shots of far buildings

Different Results from Online Calculators

Problem: Other FoV calculators give different numbers

Possible Causes:

1. Rounding Differences

  • Minor variations due to rounding
  • Differences of inches are normal
  • All calculators are approximations

2. Different Formulas

  • Some use simplified formulas
  • Some account for lens variations
  • Results should be close (within 5%)

3. Sensor Dimension Variations

  • “APS-C” isn’t standardized
  • Actual sensor sizes vary slightly by model
  • Use exact dimensions for accuracy

4. Distance Measurement Point

  • Some calculators use lens position
  • Others use sensor plane position
  • Can cause 2-3 inch differences

Can’t Find My Sensor Size

Problem: My camera’s sensor isn’t in the capture plane list

Solution:

  1. Google “[your camera model] sensor dimensions”
  2. Find width and height in millimeters
  3. Look for matching capture plane:
    • Full Frame: 36×24mm
    • APS-C Canon: 22.2×14.8mm
    • APS-C Nikon/Sony: 23.5×15.6mm
    • Micro Four Thirds: 17.3×13mm
  4. Select closest match

If no close match:

  • Select nearest standard size
  • Results will be approximate
  • Consider adding custom sensor option in gear

Frequently Asked Questions

General Questions

Q: Does field of view change if I crop my image?

A: The original FoV doesn’t change, but cropping effectively narrows your field of view. If you crop to 50% of width, your effective horizontal FoV is halved. Use the calculator with your original uncropped framing.

Q: Why do phone cameras have such wide FoV?

A: Smartphone cameras have tiny sensors and very short focal lengths (typically 4-6mm actual focal length). To give perspective similar to 24mm on full frame, they use wide-angle lenses. This is why phones are great for landscapes but struggle with narrow FoV shots.

Q: What’s the difference between FoV and angle of view?

A: They’re the same thing! “Field of View” and “Angle of View” are interchangeable terms. Both refer to how much of the scene the lens can see.

Q: Does aperture affect field of view?

A: No. Field of view is determined only by:

  • Focal length
  • Sensor size
  • Distance (for linear dimensions)

Aperture affects depth of field and exposure, but not field of view.

Q: Can I use this for video?

A: Yes! FoV calculations apply equally to video and stills from the same camera/lens. However, note:

  • Some cameras crop sensor in video mode
  • Check if your camera uses full sensor width for video
  • Adjust calculations if video uses crop mode

Technical Questions

Q: What’s the formula for field of view?

A: For horizontal FoV:

Angle (degrees) = 2 × arctan(sensor_width / (2 × focal_length))

Linear dimension = 2 × distance × tan(angle / 2)

Vertical uses sensor height instead of width.

Q: Why does FoV change with crop factor?

A: Crop factor doesn’t actually change the lens. It describes how much smaller the sensor is compared to full frame. A smaller sensor captures a smaller portion of the lens’s image circle, effectively narrowing the field of view.

Q: What’s the relationship between focal length and FoV?

A: Inverse relationship:

  • 2x the focal length = half the angular FoV
  • 50mm → 100mm reduces FoV by ~50%
  • Half the focal length = double the angular FoV
  • 50mm → 25mm increases FoV by ~100%

Q: Do all 50mm lenses have the same FoV?

A: On the same sensor, yes. A 50mm is a 50mm regardless of manufacturer. However:

  • Different brands may have slight focal length variance (49mm vs. 51mm actual)
  • On different sensor sizes, same 50mm has different FoV
  • Macro lenses may have focal length breathing (changes with focus)

Q: What’s lens breathing and how does it affect FoV?

A: Lens breathing is when focal length changes with focus distance. Some lenses:

  • Marked as 50mm
  • Actually 48mm at close focus
  • Actually 52mm at infinity

This causes FoV to vary with focus. Calculator assumes constant focal length. For affected lenses, results are approximate.

Q: How accurate are FoV calculations?

A: Very accurate for most purposes:

  • Angular FoV: within 1-2 degrees
  • Linear FoV: within a few inches at typical distances
  • Assumes rectilinear lens (straight lines stay straight)
  • Doesn’t account for distortion

For fisheye or unusually designed lenses, results are approximations.

Practical Questions

Q: How do I measure distance accurately?

A: Several methods:

Laser Measure (Best)

  • Point at subject
  • Read distance
  • Accurate to fractions of inch

Tape Measure

  • Measure from camera to subject
  • Measure from sensor plane (often marked on camera top)
  • Manual but accurate

Pacing

  • Count steps (know your stride length)
  • Approximate but quick
  • Good for rough planning

Rangefinder App

  • Some phone apps use camera/sensors
  • Accuracy varies
  • Better than guessing

Q: Which is more important: horizontal or vertical FoV?

A: Depends on:

Landscape Orientation: Horizontal FoV most critical

  • Width determines if scene fits
  • Most common camera orientation

Portrait Orientation: Vertical FoV most critical

  • Height determines if subject fits
  • Common for portraits, products

Video: Horizontal usually matters more

  • Most video is 16:9 landscape
  • Width determines framing

Consider both when planning shoots.

Q: How much margin should I add to calculated FoV?

A: Add margin for:

Subject Movement: 10-20%

  • Events, children, sports
  • Allows for unpredictability

Composition Breathing Room: 15-30%

  • Professional compositions need space
  • Avoid cutting off subjects at frame edge

Safety Factor: 10%

  • Account for measurement errors
  • Lens variation
  • Better too wide than too tight

No Margin Needed:

  • Static products
  • Controlled studio environments
  • When space is constrained

Q: Can I use FoV calculator for astrophotography?

A: Yes! Especially useful for:

Calculating Coverage:

  • How much sky fits in frame
  • What constellations/features you can capture
  • Use infinity mode

Planning Panoramas:

  • How many shots needed to cover area
  • Determine overlap between frames

Lens Selection:

  • Wide angle for Milky Way (16-24mm)
  • Moderate for constellations (35-50mm)
  • Telephoto for moon/planets (200mm+)

Distance is infinity for all celestial objects.

Q: Does image stabilization affect FoV?

A: No. Image stabilization (IS, VR, OSS) prevents camera shake but doesn’t change:

  • Field of view
  • Focal length
  • Coverage area

IS only affects motion blur, not framing.

App-Specific Questions

Q: Why do I need to add my camera to Gear?

A: Sensor size dramatically affects field of view. A 50mm lens on:

  • Full Frame: 40° horizontal FoV
  • APS-C (1.5x): 27° horizontal FoV
  • Micro Four Thirds: 20° horizontal FoV

Without your actual camera’s sensor size, calculations would be wrong.

Q: Can I use the same gear list in DoF calculator?

A: Yes! The gear list is shared between:

  • Depth of Field calculator
  • Field of View calculator
  • Any other photography tools in GeoLog

Add your gear once, use everywhere.

Q: Do my calculations sync between devices?

A: If using GeoLog with cloud sync enabled, your gear list syncs across devices. Otherwise, gear lists are stored locally per device.

Q: What if I shoot with multiple cameras?

A: Add all your cameras to Gear:

  • Each camera can have its own lens collection
  • Select appropriate camera for each calculation
  • Calculator saves your last selection per tool

Q: Can I export calculation results?

A: Currently, results are display-only. For documentation:

  • Take screenshots of results
  • Manually note key measurements
  • Use results to inform shooting plan

Future versions may add export functionality.

Appendix: FoV Formulas

For those interested in the mathematics:

Angular Field of View

Horizontal FoV (degrees):

FoVh = 2 × arctan(sensor_width / (2 × focal_length))

Vertical FoV (degrees):

FoVv = 2 × arctan(sensor_height / (2 × focal_length))

Diagonal FoV (degrees):

FoVd = 2 × arctan(sensor_diagonal / (2 × focal_length))

Linear Field of View

Horizontal dimension at distance d:

Width = 2 × d × tan(FoVh / 2)

Vertical dimension at distance d:

Height = 2 × d × tan(FoVv / 2)

Diagonal dimension at distance d:

Diagonal = 2 × d × tan(FoVd / 2)

Crop Factor

Crop factor:

CF = full_frame_diagonal / sensor_diagonal
CF = 43.27mm / sensor_diagonal

Equivalent focal length:

Equivalent_FL = actual_FL × crop_factor

Note: This calculator uses actual focal length and actual sensor dimensions, not equivalents.

Quick Reference: Common FoV Values

Full Frame Camera

Wide Angle Lenses:

  • 14mm: 114° horizontal, 84° vertical
  • 16mm: 107° horizontal, 79° vertical
  • 20mm: 94° horizontal, 70° vertical
  • 24mm: 84° horizontal, 62° vertical

Normal Lenses:

  • 35mm: 63° horizontal, 44° vertical
  • 50mm: 47° horizontal, 32° vertical

Telephoto Lenses:

  • 85mm: 28° horizontal, 19° vertical
  • 135mm: 18° horizontal, 12° vertical
  • 200mm: 12° horizontal, 8° vertical
  • 400mm: 6° horizontal, 4° vertical

APS-C Camera (1.5x crop)

Multiply full frame FoV by 0.67 for approximate values.

Micro Four Thirds (2x crop)

Divide full frame FoV by 2 for approximate values.

Thank you for using the GeoLog Field of View Calculator!

For more photography tools and location-based workflows, explore the other features in GeoLog.

GeoLog FoV Calculator Manual v1.0 © 2026 Richard Cox. All rights reserved.