全画幅等效值
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景深等效光圈： —
| 传感器 | 裁切系数 | 等效焦距（mm） | 等效光圈（景深） |
|---|
计算原理
视野会随裁切系数缩放：等效焦距 = 焦距 × （原始裁切系数 / 目标裁切系数）。景深的缩放方式相同：等效光圈 = 光圈 × （原始裁切系数 / 目标裁切系数）。曝光值不变——f/2.8 的镜头在任何传感器上测光值仍为 f/2.8。
裁切系数是相对于 36×24 mm 全画幅传感器（对角线 ≈ 43.27 mm）而言的。
📷 摄影
裁切系数与等效焦距计算器
在全画幅、佳能APS-C（1.6x）、索尼/尼康APS-C（1.5x）、M43微单、1英寸、富士GFX和飞思传感器之间换算焦距和光圈。
计算原理
Two multiplications drive the whole tool: equivalent focal length = focal length x (source crop factor / target crop factor), and equivalent aperture = f-number x that same ratio. The headline result converts your lens to its full-frame equivalent, and the table underneath repeats the calculation against all seven sensors at once. Crop factors are ratios of sensor diagonal to full frame's 43.27 mm, so Micro Four Thirds at 2.0x sees half the field of view.
Set Source sensor first. The dropdown runs Phase One IQ4 (0.64x), Fuji GFX 50/100 (0.79x), Full Frame (1.0x), APS-C Nikon / Sony (1.5x), APS-C Canon (1.6x), Micro Four Thirds (2.0x) and 1-inch (2.7x). Focal length and aperture default to 50 mm and f/1.8, and six preset buttons load 24 mm f/1.4 through 200 mm f/2.8. The row matching your source sensor is highlighted in the comparison table.
The equivalent aperture column describes depth of field and total light gathered, not exposure. An f/1.8 lens still meters at f/1.8 on every sensor, so never dial the equivalent number into your camera. The tool also uses nominal crop factors rather than each body's exact sensor dimensions, ignores the aspect-ratio differences between formats such as 4:3 Micro Four Thirds against 3:2 full frame, and says nothing about noise differences between sensor sizes.
常见问题
What is a 50mm lens on APS-C in full-frame terms?
With APS-C Canon (1.6x) selected, a 50 mm f/1.8 reports as 80 mm at f/2.88 full-frame equivalent. On Nikon or Sony APS-C at 1.5x the same lens reports 75 mm at f/2.70. The framing and background blur change; the physical lens does not.
Why does the aperture change as well as the focal length?
Depth of field depends on the physical diameter of the aperture relative to the format. Multiplying the f-number by the crop factor gives the full-frame f-number that would produce the same depth of field and collect the same total light across the frame.
Do I lose a stop of exposure on a crop sensor?
No. Exposure is set by f-number, shutter speed and ISO regardless of sensor size, and the tool never adjusts your metering. The equivalent aperture figure exists purely to compare background blur and total light between different formats.
What crop factor does Micro Four Thirds use?
The tool uses 2.0x, so a 25 mm Micro Four Thirds lens frames like 50 mm on full frame. One-inch sensors are 2.7x. Medium format goes the other way: Fuji GFX is 0.79x and Phase One IQ4 is 0.64x, values below 1.0 that widen rather than crop.
Can I convert directly between two crop sensors?
Yes. Set Source sensor to the format you shoot, then read the row for the format you want to compare against. Because the table divides by the target's crop factor, Micro Four Thirds to APS-C Canon works without going through full frame first.
别名
crop factor calculatorfull frame equivalentm43 to full frameaps-c equivalent focal length
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