裁切系数计算器
本裁切系数计算器计算 APS-C、M43、1 英寸或其他裁切传感器相机上任意镜头的全画幅等效焦距、等效光圈和视角。输入焦距、光圈和传感器类型，即时查看您的镜头与全画幅配置的对比。
Crop Factor Calculator
Enter your lens focal length, aperture, and select your camera sensor to calculate the full-frame equivalent focal length, aperture, and field of view.
Common focal lengths:
Related calculators:
常见问题
摄影中的裁切系数是什么？
裁切系数（也称焦距乘数）是全画幅 35mm 传感器对角线（43.27mm）与较小相机传感器对角线之比。它告诉你与全画幅相比，视野角度缩小了多少。例如，裁切系数为 1.5x 的 APS-C 传感器在使用相同镜头时，拍摄的视角比全画幅相机窄 1.5 倍。
如何计算裁切传感器的等效焦距？
将实际镜头焦距乘以传感器裁切系数。公式：等效焦距 = 实际焦距 × 裁切系数。例如，50mm 镜头安装在裁切系数为 1.5x 的 APS-C 相机上，等效焦距 = 50 × 1.5 = 75mm。这意味着它拍摄的场景与全画幅相机上的 75mm 镜头相同。
APS-C 传感器的裁切系数是多少？
APS-C 传感器的裁切系数因制造商略有不同。佳能 APS-C 传感器裁切系数为 1.6x，尼康、索尼、富士和宾得的 APS-C 传感器裁切系数为 1.5x。这意味着佳能 APS-C 上的 50mm 镜头等效 80mm（50 × 1.6），而尼康 APS-C 上等效 75mm（50 × 1.5）。
微型四三系统（MFT）的裁切系数是多少？
微型四三系统相机（奥林巴斯/OM System 和松下）的裁切系数为 2.0x。这意味着任何镜头焦距需要乘以 2 才能得到全画幅等效值。25mm MFT 镜头的视角与全画幅上的 50mm 镜头相同，12mm 镜头等效 24mm——使 MFT 镜头比全画幅看起来更像长焦镜头。
裁切系数会影响光圈和景深吗？
在比较不同传感器尺寸的相同取景效果时，裁切系数会影响等效光圈和景深。求等效光圈：等效光圈 = 实际光圈 × 裁切系数。APS-C 1.5x 相机上的 50mm f/1.4 镜头，景深与全画幅上的 75mm f/2.1 镜头相同。全画幅相机在等效设置下具有浅景深和弱光性能的优势。
裁切系数如何影响视野？
裁切系数使视野角度比全画幅更窄。对角线视野计算：FOV = 2 × arctan(传感器对角线 / (2 × 焦距))。全画幅相机上 50mm 镜头的对角线视野约 46.8°。相同镜头在 APS-C 1.5x 相机上只拍摄约 31.7°。要在 APS-C 上获得相同视野，需要约 33mm 的镜头（50 ÷ 1.5）。
裁切系数越高越好还是越低越好？
这取决于你的拍摄需求，没有绝对好坏之分。裁切系数越高（传感器越小）任何镜头都能获得更多远摄倍率，这对野生动物、体育和鸟类摄影有利。但这也使广角拍摄更困难，降低了浅景深能力，与相同技术的大传感器相比弱光性能通常较差。较大的传感器（较低裁切系数）通常提供更好的弱光性能、更多虚化控制和更宽的视角。
1 英寸传感器的裁切系数是多少？
1 英寸传感器（13.2 × 8.8mm）的裁切系数约为 2.7x。这意味着 1 英寸传感器上的 10mm 镜头提供与全画幅上 27mm 镜头类似的视野。常见的 1 英寸传感器相机包括索尼 RX100 系列、松下 LX100 和许多大疆无人机相机。
Understanding Crop Factor in Photography
What is Crop Factor?
Crop factor (also called focal length multiplier) is the ratio between the diagonal of a full-frame 35mm sensor (43.27mm) and the diagonal of a smaller camera sensor. It tells you how much smaller your sensor is compared to a full-frame reference, and by how much the effective angle of view is narrowed.
A full-frame sensor measures approximately 36mm × 24mm. Any sensor smaller than this has a crop factor greater than 1.0. When you mount a lens designed for full-frame on a crop-sensor camera, only the center portion of the image circle is used — effectively "cropping" the view and making subjects appear closer.
Crop Factor Formula:
Crop Factor = 43.27mm (FF diagonal) ÷ Sensor Diagonal (mm)
Equivalent Focal Length = Actual Focal Length × Crop Factor
For example, a 50mm lens on an APS-C camera with a 1.5x crop factor behaves like a 75mm lens would on full frame — giving a narrower field of view and more telephoto compression.
Common Sensor Sizes
Different camera manufacturers use different sensor sizes, each with a specific crop factor. Here is a reference table of the most common sensor formats:
| Sensor Format | Typical Size (mm) | Crop Factor | Common Cameras |
|---|---|---|---|
| Full Frame | 36 × 24 | 1.0× | Sony A7, Nikon Z6, Canon R6 |
| APS-C (Canon) | 22.3 × 14.9 | 1.6× | Canon EOS 90D, M6 II, R7 |
| APS-C (Nikon/Sony/Fuji) | 23.5 × 15.6 | 1.5× | Nikon Z50, Sony A6700, Fuji X-T5 |
| Micro Four Thirds | 17.3 × 13.0 | 2.0× | Olympus OM-5, Panasonic G9 |
| 1-Inch | 13.2 × 8.8 | 2.7× | Sony RX100, Nikon Z30 (1" CX), DJI drones |
| 1/2.3-Inch | 6.17 × 4.55 | 5.6× | Compact cameras, action cams, smartphones |
Equivalent Focal Length
The equivalent focal length is the focal length on a full-frame camera that produces the same field of view as your lens on a crop sensor. It is the most common use of crop factor calculations.
Example 1: Portrait Lens on APS-C
A 50mm f/1.8 lens mounted on a Nikon APS-C camera (1.5× crop factor):
Equivalent FL = 50mm × 1.5 = 75mm
The lens behaves like a 75mm portrait lens on full frame — a classic mid-telephoto focal length ideal for portraits.
Example 2: Wide-Angle on Micro Four Thirds
A 12mm lens on a Micro Four Thirds camera (2.0× crop factor):
Equivalent FL = 12mm × 2.0 = 24mm
The 12mm MFT lens gives the same wide-angle view as a 24mm lens on full frame — a popular focal length for landscapes and interiors.
Example 3: Telephoto Advantage
A 300mm lens on a Canon APS-C camera (1.6× crop factor):
Equivalent FL = 300mm × 1.6 = 480mm
Wildlife and sports photographers often prefer APS-C sensors for this "free" reach advantage.
How Crop Factor Affects Depth of Field
Crop factor affects depth of field (DOF) in an important but often misunderstood way. To achieve the same framing (field of view) and depth of field on a crop sensor as on full frame, you need to account for both focal length and aperture.
When comparing two cameras with the same framing, the crop sensor camera produces more depth of field than the full-frame camera at the same aperture. This is because the crop sensor uses a shorter focal length to achieve the same framing, and shorter focal lengths inherently produce more DOF.
DOF Equivalence Rule:
Equivalent Aperture = Actual Aperture × Crop Factor
To match the DOF and light-gathering of f/1.4 on full frame, an APS-C camera (1.5×) would need f/0.93 — which does not exist. This is the DOF disadvantage of crop sensors for portrait bokeh.
In practice: if you want shallow background blur (bokeh) comparable to a full-frame camera, you need a lens with a proportionally wider aperture on a crop sensor. A 35mm f/1.4 on APS-C gives similar DOF to a 50mm f/2.0 on full frame.
Field of View Comparison
Field of view (FOV) is the angular extent of the scene captured by a lens-sensor combination. It is measured diagonally in degrees and is the primary reason crop factor matters — a smaller sensor captures a narrower slice of the scene.
The diagonal FOV formula used by this calculator is:
FOV = 2 × arctan(sensor diagonal / (2 × focal length))
Where sensor diagonal = 43.27mm ÷ crop factor (derived from the full-frame 43.27mm diagonal)
For example, a 50mm lens on full frame has a diagonal FOV of approximately 46.8°. The same lens on an APS-C 1.5× sensor captures only 31.7°. To get a similar 46.8° FOV on the APS-C camera, you would need approximately a 33mm lens.
| Focal Length | FOV Full Frame | FOV APS-C (1.5×) | FOV MFT (2.0×) |
|---|---|---|---|
| 14mm | 114.2° | 84.1° | 62.8° |
| 24mm | 73.7° | 53.1° | 39.6° |
| 35mm | 54.4° | 38.2° | 28.6° |
| 50mm | 46.8° | 31.7° | 23.6° |
| 85mm | 28.6° | 19.1° | 14.3° |
| 200mm | 12.4° | 8.3° | 6.2° |
Crop Factor and Aperture Equivalence
When comparing lenses across different sensor formats for both field of view and depth of field, you need to apply the crop factor to both focal length and aperture. This gives you the "full-frame equivalent" spec of a lens on a crop sensor.
- A 25mm f/1.4 lens on Micro Four Thirds (2.0×) is equivalent to a 50mm f/2.8 on full frame.
- A 23mm f/2.0 on APS-C Sony (1.5×) is equivalent to a 35mm f/3.0 on full frame.
- A 12mm f/2.0 on Micro Four Thirds (2.0×) is equivalent to a 24mm f/4.0 on full frame.
This is why full-frame cameras are generally preferred for low-light photography — achieving an equivalent f/1.4 on full frame is far easier and cheaper than finding an f/0.7 lens for a small sensor camera.
However, crop sensors have real advantages: smaller, lighter bodies and lenses; longer effective reach for wildlife and sports; and lower cost at the same resolution. The right format depends entirely on your photographic needs.