Crop Factor Calculator
Calculate how sensor size affects focal length and field of view. Understand the relationship between different camera sensors and lens performance.
Calculate Your Crop Factor Calculator
What is Crop Factor?
Crop factor refers to the ratio of the dimensions of a camera's sensor compared to a full-frame (35mm) sensor. It helps photographers understand how a lens will behave on different camera bodies with different sensor sizes.
How Crop Factor Works
When you use a lens designed for a full-frame camera on a camera with a smaller sensor, the smaller sensor captures only the central portion of the image that would have been captured by a full-frame sensor. This is equivalent to "cropping" the full-frame image, hence the term "crop factor."
Effects on Focal Length
The focal length of a lens doesn't actually change when mounted on cameras with different sensor sizes. However, the field of view does change, creating an effect similar to using a lens with a longer focal length.
For example, a 50mm lens on an APS-C camera with a 1.5x crop factor will have a field of view equivalent to a 75mm lens on a full-frame camera (50mm × 1.5 = 75mm).
Effects on Aperture and Depth of Field
While the actual aperture of the lens remains the same, the depth of field changes when using a lens on a camera with a different sensor size. A smaller sensor with a higher crop factor will generally produce a greater depth of field at the same aperture setting compared to a full-frame camera.
For equivalent framing and perspective, the depth of field on a crop sensor is approximately equivalent to that of a full-frame camera at an aperture value multiplied by the crop factor.
Common Crop Factors
- Full-frame (35mm): 1.0× (reference)
- APS-C (Canon): 1.6×
- APS-C (Nikon, Sony, Pentax): 1.5×
- Micro Four Thirds: 2.0×
- 1-inch sensors: 2.7×
- 1/2.3-inch sensors (common in compact cameras): 5.6×
Practical Applications
Understanding crop factor helps photographers:
- Choose appropriate lenses for their camera
- Calculate equivalent focal lengths when switching between camera systems
- Understand differences in field of view and depth of field between different camera systems
- Determine whether a lens will provide the desired field of view on their specific camera
Advantages of Different Sensor Sizes
Full-frame advantages: Better low-light performance, shallower depth of field, wider field of view with wide-angle lenses.
Crop sensor advantages: Extended reach for telephoto photography, typically smaller and lighter cameras and lenses, potentially greater depth of field.
Use our Crop Factor Calculator above to easily determine equivalent focal lengths and apertures between different camera systems.
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Frequently Asked Questions
Crop factor is the ratio of the size of a full-frame sensor (36mm × 24mm) to the size of a smaller camera sensor. It helps photographers understand how lenses will behave on cameras with different sensor sizes.
For example, an APS-C sensor with a crop factor of 1.5× means that the field of view is 1.5 times narrower than on a full-frame camera with the same lens.
To calculate the full-frame equivalent focal length, multiply the actual focal length of your lens by your camera's crop factor.
For example, if you're using a 50mm lens on an APS-C camera with a 1.5× crop factor, the full-frame equivalent focal length would be 50mm × 1.5 = 75mm.
Crop factor itself doesn't directly affect image quality. However, different sensor sizes may have different pixel densities, dynamic range, and noise characteristics that can impact image quality.
Larger sensors typically capture more light and often provide better low-light performance, while smaller sensors with high pixel counts may capture more detail in good lighting conditions.
Yes, crop factor affects the apparent depth of field. For the same aperture setting, a camera with a larger sensor (smaller crop factor) will produce a shallower depth of field than a camera with a smaller sensor when the subject framing is identical.
To achieve the same depth of field on a crop sensor as you would on a full-frame sensor, you would need to use an aperture that is wider by a factor equal to the crop factor. For instance, f/2.8 on a full-frame is approximately equivalent to f/1.8 on a 1.5× crop sensor in terms of depth of field (though the exposure remains the same).
The most common crop factors in digital cameras are:
- Full-frame: 1.0× (reference)
- APS-C (Canon): 1.6×
- APS-C (Nikon, Sony, Pentax): 1.5×
- Micro Four Thirds: 2.0×
- 1-inch sensors: 2.7×
- Smartphone sensors: Usually 5-7×
If you're using lenses designed specifically for your camera's sensor size (like DX lenses for Nikon APS-C cameras), the focal length marked on the lens already gives you the actual field of view for that camera.
However, calculating the full-frame equivalent can still be useful for comparing the field of view to full-frame systems or when discussing photography with others who may use different systems.
Neither higher nor lower crop factors are inherently better or worse—they simply offer different advantages and limitations.
Higher crop factors (smaller sensors) provide more "reach" for telephoto photography and often result in smaller, lighter camera systems. Lower crop factors (larger sensors) typically offer better low-light performance, wider fields of view with wide-angle lenses, and the ability to achieve shallower depth of field.
Crop factor and teleconverters both effectively extend the focal length, and their effects are multiplicative.
For example, if you use a 200mm lens with a 1.4× teleconverter on a camera with a 1.5× crop factor, the effective focal length would be: 200mm × 1.4 × 1.5 = 420mm in full-frame equivalent terms.
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