Crop Factor Calculator
Convert focal length and aperture between camera systems (Full Frame, APS-C, Micro Four Thirds, and more).
What Is Crop Factor?
Crop factor is a multiplier that compares a camera sensor size to a 35mm full-frame sensor. Because smaller sensors capture a narrower field of view with the same lens, the image appears more “zoomed in.” This is why photographers often talk about a “35mm equivalent focal length.”
For example, a 35mm lens on an APS-C camera (1.5x crop) gives a similar field of view to a 52.5mm lens on full frame.
How This Crop Factor Calculator Helps
This calculator answers three practical questions quickly:
- Field of view conversion: What focal length on another system gives the same framing?
- 35mm equivalent focal length: What does your lens “feel like” in full-frame terms?
- Depth of field equivalence: What aperture gives a similar blur/background separation across formats?
Formulas Used
35mm equivalent focal length = focal length × source crop factor
Target focal length for same field of view = focal length × (source crop ÷ target crop)
Target aperture for similar depth of field = aperture × (source crop ÷ target crop)
These formulas are ideal for planning lens purchases, comparing systems, and deciding what setup to bring for travel, portraits, wildlife, or video.
Common Crop Factors
- Full Frame: 1.0x
- APS-C (Nikon/Sony/Fuji): 1.5x
- APS-C (Canon): 1.6x
- Micro Four Thirds: 2.0x
- 1-inch Sensor: 2.7x
- Medium Format (some models): less than 1.0x (for example ~0.79x)
Real-World Examples
Example 1: Street Photography
If you like a 35mm full-frame look and shoot APS-C (1.5x), use roughly a 23mm lens. 23 × 1.5 ≈ 34.5mm equivalent.
Example 2: Portraits
A classic 85mm portrait framing on full frame is close to 56mm on APS-C 1.5x, or 42.5mm on Micro Four Thirds.
Example 3: Wildlife Reach
A 300mm lens on Micro Four Thirds (2.0x) gives the field of view of a 600mm lens on full frame, which can be very useful for birds and distant subjects.
Important Notes About Aperture Equivalence
Exposure does not change when converting equivalent aperture between formats. f/2.8 still transmits f/2.8 light regardless of sensor size. Equivalence calculations are about matching depth of field and overall rendering style, not changing exposure settings.
Tips When Comparing Camera Systems
- Compare both focal length and aperture, not focal length alone.
- Remember sensor aspect ratios can affect framing slightly.
- Lens availability matters: not every focal length/aperture combo exists on every mount.
- Use equivalence as a planning tool, not an absolute rule.
Bottom Line
A crop factor calculator removes guesswork. Whether you are moving from APS-C to full frame, comparing Micro Four Thirds lenses, or choosing travel gear, equivalent focal length and depth-of-field conversions help you make faster and better decisions.