android 单反相机
Every time we talk about the digital cameras, one thing that comes up is the “crop factor” of the sensor. Let’s dig a bit more into it and explain why it matters.
每次我们谈论数码相机时，出现的一件事就是传感器的“裁剪系数”。 让我们进一步研究它，并解释它为什么重要。
不同的相机，不同的传感器 (Different Cameras, Different Sensors)
Digital cameras don’t all have identically sized sensors; there are a couple of different standards. The leading standard—used by manufacturers in their professional and high-end cameras—is 35mm or full frame. The sensor is approximately the same size as a piece of 35mm film (36mm x 24mm) which was the most popular film format.
数码相机并非都具有相同大小的传感器。 有几个不同的标准。 制造商在其专业和高端相机中使用的领先标准是35mm或全画幅。 该传感器的尺寸与一块35mm胶片(36mm x 24mm)的尺寸大致相同，后者是最受欢迎的胶片格式。
Digital sensors, however, are pretty expensive to manufacture. The bigger the sensor, the more it costs. For this reason, manufacturers also make cameras with smaller sensors. By far the most common standard is APS-C which is based on the size of Advanced Photo Systems film size. Exact sensor sizes vary a bit between manufacturers, but they’re typically between 22.5mm x 15mm and 24mm x 16mm.
然而，数字传感器制造起来相当昂贵。 传感器越大，成本越高。 因此，制造商还制造了带有较小传感器的相机。 到目前为止，最常见的标准是APS-C，它基于Advanced Photo Systems胶卷的尺寸。 确切的传感器尺寸在制造商之间略有不同，但通常在22.5mm x 15mm和24mm x 16mm之间。
While 35mm and APS-C are the primary standards, there are other sensor sizes too. The one in your phone is around 9mm x 6mm. Digital medium format cameras (link) can have sensors that are 50mm x 40mm.
虽然35mm和APS-C是主要标准，但还有其他尺寸的传感器。 手机中的一个约为9mm x 6mm。 数码中画幅相机(链接)可以具有50mm x 40mm的传感器。
传感器和视野 (Sensors and Field of View)
Now, to get crop factor, you need to understand two things:
现在，要获取作物因子，您需要了解两件事：
The focal length of a lens is a physical property that stays constant regardless of what camera you use.
镜头的焦距是一种物理特性 ，无论您使用哪种相机，其焦距都保持恒定。
The focal length of a lens is what determines its field of view.
镜头的焦距决定了它的视场 。
But here’s the thing: The field of view you get from a lens of a given focal lengthdoesn’tstay constant. It depends on what camera you use.
但这就是问题：从给定焦距的镜头获得的视野不会保持恒定。 这取决于您使用的相机。
Let’s look at this in action. In the image below, courtesy of Sony, you can see how a given lens projects an image circle onto a full frame sensor and the resulting image.
让我们看看实际情况。 在下面的图像中， 由Sony提供 ，您可以看到给定的镜头如何将像圈投影到全画幅传感器上以及得到的图像。
Now, look at how the same lens projects an image circle of the same scene onto an APS-C sensor.
现在，看看相同的镜头如何将相同场景的像圈投影到APS-C传感器上。
Since the sensor is smaller, the area that it samples from the image circle is smaller. This has the effect of reducing the field of view relative to the full frame sensor.
由于传感器较小，因此它从像圈采样的区域较小。 这具有减小相对于全帧传感器的视野的效果。
Nothing about the lens has changed; it’s just that for the image to be in focus, the sensor has to sit a certain distance from the lens which means a smaller sensor will always have a narrower field of view when using a lens of the same focal length.
镜头什么都没有改变。 只是为了使图像清晰，传感器必须与镜头保持一定的距离，这意味着较小的传感器在使用相同焦距的镜头时将始终具有较窄的视野。
作物因子 (Crop Factor)
So to recap:
因此，回顾一下：
Different cameras use different sized sensors. 35mm full frame is the main standard.不同的相机使用不同大小的传感器。 35mm全画幅是主要标准。 Smaller sensors have a narrower field of view than larger sensors when using lenses of the same focal length.当使用相同焦距的镜头时，较小的传感器比较大的传感器具有更窄的视野。
Since photography is based around incredibly well understood and predictable optical principles, we can calculate the relative field of view for any combination of lens and sensor size when compared to a full frame camera. This is the crop factor. Fortunately, the maths has already been done for us, so you can put your pencil away.
由于摄影是基于令人难以置信的良好理解和可预测的光学原理，因此与全画幅相机相比，我们可以计算镜头和传感器尺寸的任何组合的相对视场。 这是作物因素。 幸运的是，数学已经为我们完成，因此您可以放下铅笔了。
The most common crop factor you’ll encounter is 1.5x. That’s the crop factor for most APS-C cameras. It means that a 50mm lens on a crop sensor camera has an equivalent field of view to a 75mm lens on a full frame camera (50mm x 1.5 = 75mm). Bear in mind; this is just an approximation. Canon’s crop factor is actually about 1.6x, and most Nikon and Sony cameras are normally closer to 1.52x. If you’re curious about the exact crop factor of your camera, look up its specs online.
您会遇到的最常见的裁剪系数是1.5倍。 这是大多数APS-C相机的收成因素。 这意味着作物传感器相机上的50mm镜头具有与全画幅相机上的75mm镜头相同的视场(50mm x 1.5 = 75mm)。 记住; 这只是一个近似值。 佳能的裁剪系数实际上约为1.6倍，大多数尼康和索尼相机通常接近1.52倍。 如果您对相机的确切裁切系数感到好奇，请在线查找其规格。
Phone cameras have a crop factor of about 7x. The wide angle lens on your iPhone has an actual focal length of 3.99mm; this gives it a full frame equivalent focal length of about 28mm given the tiny size of the sensor.
手机摄像头的裁剪系数约为7倍。 iPhone上的广角镜头的实际焦距为3.99毫米； 在传感器很小的情况下，这使它的全帧等效焦距约为28mm。
Crop factor also cuts both ways. Medium format cameras have a crop factor that’s less than 1. For example, the Hasselblad H6D-100c has a crop factor of 0.65x. This means a 50mm lens has a full frame equivalent focal length of 32.5mm. That’s a much wider field of view.
作物因素也有双重作用。 中画幅相机的裁切系数小于1。例如，哈苏H6D-100c的裁切系数为0.65倍。 这意味着50mm镜头的全画幅等效焦距为32.5mm。 那是更广阔的视野。
为什么你应该关心 (Why You Should Care)
At How-To Geek, we believe you should understand how your camera works so you can better control what it does. Focal length is the biggest factor in determining how your images look, so it’s important that you know how different focal lengths work with your camera.
在How-To Geek，我们相信您应该了解相机的工作原理，以便更好地控制相机的工作。 焦距是决定图像外观的最大因素，因此了解相机如何使用不同的焦距非常重要。
For example, a 35mm lens (super popular with the great street photographers like Henri Cartier-Bresson) is a wide angle lens on a full frame camera but a normal lens on a crop sensor camera. If you wanted to recreate the look of Cartier-Bresson’s photos with your crop sensor camera, you’d need to use a 24mm lens.
例如，35mm镜头(在Henri Cartier-Bresson等街头摄影师中很受欢迎)是全画幅相机上的广角镜头，而农作物传感器相机上是普通镜头 。 如果要使用裁剪传感器相机重现Cartier-Bresson照片的外观，则需要使用24mm镜头。
翻译自: /366983/what-is-dslr-crop-factor-and-why-should-i-care/
android 单反相机
