Crop Factor Calculator

Calculate crop factor and 35mm equivalent focal length for any camera sensor.

Enter your camera's sensor dimensions and focal length to calculate the crop factor and see how it affects your field of view compared to full-frame.

Crop Factor Examples

See how different sensor sizes affect crop factor and field of view with the same focal length.

Full Frame Sensor, 50mm Lens

Full Frame Sensor

Standard full-frame sensor with a classic 50mm lens.

Sensor Width: 36 mm

Sensor Height: 24 mm

Focal Length: 50 mm

APS-C Sensor, 35mm Lens

APS-C Sensor

APS-C sensor with a wide-angle 35mm lens.

Sensor Width: 22.3 mm

Sensor Height: 14.9 mm

Focal Length: 35 mm

Micro Four Thirds, 25mm Lens

Micro Four Thirds

Micro Four Thirds sensor with a standard 25mm lens.

Sensor Width: 17.3 mm

Sensor Height: 13 mm

Focal Length: 25 mm

1-inch Sensor, 18mm Lens

1-inch Sensor

Compact 1-inch sensor with an ultra-wide 18mm lens.

Sensor Width: 13.2 mm

Sensor Height: 8.8 mm

Focal Length: 18 mm

Other Titles
Understanding Crop Factor: A Comprehensive Guide
Learn how sensor size affects your photography and lens selection

What is Crop Factor?

  • Definition and Basic Concept
  • Why Crop Factor Matters in Photography
  • Historical Context: 35mm Film Standard
Crop factor is a numerical value that describes how much smaller a camera's sensor is compared to a full-frame (35mm) sensor. It's calculated by dividing the diagonal of a full-frame sensor (43.27mm) by the diagonal of your camera's sensor.
The 35mm Film Standard
The 35mm film format (36mm × 24mm) became the industry standard for professional photography. When digital cameras were introduced, many used smaller sensors, creating the need to understand how these smaller sensors affect the field of view compared to the traditional 35mm format.
Impact on Photography

Crop Factor in Practice

  • A crop factor of 1.5x means your sensor is 1.5 times smaller than full-frame.
  • The same 50mm lens on different sensors will give different fields of view.

Step-by-Step Guide to Using the Calculator

  • Finding Your Sensor Dimensions
  • Entering Focal Length Data
  • Interpreting the Results
To use the crop factor calculator, you need to know your camera's sensor dimensions and the focal length of your lens. Most camera manufacturers provide sensor specifications in their technical documentation.
Finding Sensor Information
Sensor dimensions can usually be found in your camera's manual, on the manufacturer's website, or in online camera databases. Common sensor formats include Full Frame (36×24mm), APS-C (22.3×14.9mm), and Micro Four Thirds (17.3×13mm).
Understanding Results

How to Use

  • Enter 36mm width and 24mm height for full-frame sensors.
  • The calculator will show you the equivalent focal length on full-frame.

Real-World Applications of Crop Factor

  • Lens Selection and Planning
  • Field of View Comparison
  • Photography Style Considerations
Understanding crop factor helps photographers choose the right lenses for their intended use. It's particularly important when switching between different camera systems or when planning shoots that require specific fields of view.
Lens Selection Strategy
A photographer using an APS-C camera (1.5x crop factor) who wants the field of view of a 50mm lens on full-frame would need a 33mm lens (50÷1.5). This knowledge helps in lens purchasing decisions and kit planning.
Style Considerations

Practical Applications

  • Portrait photographers often prefer longer focal lengths for flattering perspectives.
  • Landscape photographers may choose wider lenses to capture more of the scene.

Common Misconceptions and Correct Methods

  • Crop Factor vs. Image Quality
  • Focal Length vs. Field of View
  • Sensor Size and Depth of Field
Many photographers mistakenly believe that crop factor affects image quality or that a longer focal length always means more magnification. Understanding the relationship between sensor size, focal length, and field of view is crucial for making informed decisions.
Quality Misconceptions
Crop factor doesn't inherently reduce image quality. Modern smaller sensors can produce excellent images. The main difference is in field of view and depth of field characteristics, not necessarily image quality.
Depth of Field Considerations

Misconceptions

  • Smaller sensors typically have deeper depth of field at equivalent apertures.
  • The same f/1.8 aperture behaves differently on different sensor sizes.

Mathematical Derivation and Examples

  • Crop Factor Formula
  • 35mm Equivalent Calculation
  • Field of View Relationships
The crop factor is calculated using the Pythagorean theorem to find sensor diagonals: Crop Factor = 35mm diagonal ÷ sensor diagonal, where 35mm diagonal = √(36² + 24²) = 43.27mm.
Mathematical Formula
For any sensor: Sensor Diagonal = √(width² + height²). Then: 35mm Equivalent Focal Length = Actual Focal Length × Crop Factor. This gives you the focal length needed on full-frame to achieve the same field of view.
Example Calculations

Math in Action

  • APS-C sensor (22.3×14.9mm): Diagonal = √(22.3² + 14.9²) = 26.8mm, Crop Factor = 43.27÷26.8 = 1.61x
  • 50mm lens on APS-C: 35mm equivalent = 50 × 1.61 = 80.5mm