Lens Crop Factor Calculator
Calculate effective focal length based on your camera's sensor size
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About Lens Crop Factor Calculator
This calculator uses the formula: Effective Focal Length = Lens Focal Length × Crop Factor. The crop factor is determined by comparing your sensor size to a 35mm full-frame sensor.
When planning your shots, remember that crop factor also affects depth of field. Use our Depth of Field Calculator to see how your sensor size impacts background blur.
For landscape photography with maximum sharpness, check our Hyperfocal Distance Calculator.
All calculations are performed locally in your browser. No data is sent to any server.
Frequently Asked Questions (FAQ)
What is crop factor?
Crop factor is the ratio between the 35mm full-frame sensor size and your camera's sensor size. A smaller sensor "crops" the image, making lenses appear to have a longer focal length equivalent.
Does crop factor affect aperture?
Crop factor doesn't change the physical aperture or f-number, but it does affect the equivalent depth of field. A 50mm f/1.8 on APS-C gives similar DoF to a 75mm f/2.7 on full-frame. Use our Depth of Field Calculator to compare.
How does crop factor affect low light performance?
Smaller sensors have less light-gathering area per pixel, which can affect high-ISO performance. Check our Low-Light ISO Calculator for shooting in challenging conditions.
What is the advantage of crop sensors?
Crop sensors provide extra reach for wildlife and sports photography without expensive super-telephoto lenses. They also enable smaller, lighter camera bodies and lenses.
How do I calculate minimum shutter speed with crop factor?
Use the effective focal length (lens focal length × crop factor) for the reciprocal rule. Our Handheld Shutter Speed Calculator handles this automatically.