Name: 相機基礎知識：ISO 到底是什麼？！ (Camera Basics - ISO)
Uploaded: 2026-03-14T09:05:37.000Z
Duration: 4 min 38 s

情態副詞

While shutter speed and aperture control the amount of light physically hitting the sensor, ISO controls the amount of light the camera needs and is a representation of the sensitivity of the image sensor.

快門速度和光圈控制著實際進入影像感測器的光線量，而 ISO 則控制著相機所需的光線量，代表著影像感測器的靈敏度。

As the ISO increases, the light it takes to expose the image decreases.

隨著 ISO 提高，曝光影像所需的光線就會減少。

For example, doubling the ISO from, say, 400 to 800 results in the camera needing only half as much light for the same exposure.

例如，將 ISO 從 400 加倍到 800，相機就能以一半的光線量達到相同的曝光。

This is the main reason such high ISO values are used in indoors, especially at sporting events, and

這也是為什麼在室內，特別是體育賽事，以及

拍攝野生動物時，會使用這麼高的 ISO 值。

Needing a fast shutter speed to freeze action, and

需要快速的快門速度來凍結動作，而且

often with limited light available, photographers pump up the ISO as far as they are comfortable doing.

光線常常不足，攝影師就會盡可能提高 ISO。

However, increasing your ISO doesn't come without drawbacks.

不過，提高 ISO 並非沒有缺點。

Microphones gather sound waves from a source, just like cameras gather light rays from the environment and each turn them into electrical signals, which are outputted as either a sound file for a microphone or an image for a camera.

麥克風會從音源收集聲波，就像相機從環境收集光線，然後將它們轉換成電氣訊號，輸出成音訊檔案或影像。

Now, what happens if you're trying to record something very faint, like a whisper?

現在，如果你想錄製非常微弱的聲音，像是耳語，會發生什麼事呢？

You increase the sensitivity of the microphone.

However, besides the whisper being louder, background noise is amplified as well, and

但是，除了耳語變大聲，背景噪音也會被放大，而且

you may even hear the hum of the microphone's electronics.

你甚至可能聽到麥克風電子的嗡嗡聲。

So similarly, increasing the ISO of a camera increases its sensitivity to everything, revealing any lighting artifacts as well as any electrical grain in the system.

所以，類似地，提高相機的 ISO 會提高它對所有事物的靈敏度，揭露任何光線的瑕疵以及系統中的電氣雜訊。

In the world of photography, higher ISO values don't just produce more noise, they also reduce the color accuracy and dynamic range.

在攝影的世界裡，較高的 ISO 值不僅會產生更多雜訊，還會降低色彩準確度和動態範圍。

So you should use the lowest ISO value possible at all times.

所以你應該盡可能隨時使用最低的 ISO 值。

The lowest ISO value of your camera is considered the base ISO, a term that you may come across in the future.

你相機的最低 ISO 值被認為是基礎 ISO，這個詞你未來可能會遇到。

This ISO produces the best image quality and lowest amount of noise, but

這個 ISO 能產生最佳的影像品質和最低的雜訊，但是

as stated earlier, low ISO values require lots of ambient light to properly expose the scene.

就像前面說的，低 ISO 值需要充足的環境光才能正確曝光場景。

It's also worth mentioning that not all cameras will have the same ISO profile.

還有，值得一提的是，並非所有相機的 ISO 設定都一樣。

The ISO performance of your camera largely depends on the size of the photo sites in your camera.

你相機的 ISO 表現很大程度上取決於你相機裡感光元件的大小。

When you press the shutter button of your camera, the curtain in front of the image sensor slides up, exposing the photosites to ambient light.

當你按下相機的快門按鈕時，影像感測器前方的簾幕會向上滑動，讓感光元件暴露在環境光下。

The photosites gather photons that enter through the lens, and

感光元件會收集透過鏡頭進入的光子，然後

once the exposure is over, the curtain slides over the sensor and the camera assesses the amount of photons that were gathered, converting the number into an image.

曝光結束後，簾幕會滑到感測器上方，相機會評估收集到的光子數量，並將這個數字轉換成影像。

Larger sensor cameras allow for larger photo sites, which can gather more photons, so full frame cameras have an advantage over crop sensor cameras.

感測器較大的相機可以容納較大的感光元件，能收集更多光子，所以全片幅相機比 APS-C 格式相機更有優勢。

Also, lower megapixel counts mean that each photosite is allowed to take up more space on the sensor, increasing photo site size.

另外，較低的百萬像素數量意味著每個感光元件在感測器上能佔用更多空間，增加了感光元件的大小。

However, older lower megapixel sensors are not better for low light shooting, as advances in microlens design and the silicon itself have made modern sensors more efficient.

不過，老舊的低百萬像素感測器在低光源拍攝上並不見得比較好，因為微透鏡設計和矽本身的進步，讓現代感測器更有效率。

那麼，我們什麼時候該用低 ISO 和高 ISO 呢？

Remember that in every case you should try to decrease your ISO as much as possible to retain image quality, but

請記得，在任何情況下，你都應該盡量降低 ISO 以保留影像品質，但

sometimes you may be forced to use higher ISOs.

有時候你可能不得不使用較高的 ISO。

Low ISOs are particularly useful in outdoor photography, where the sun will provide lots of light for your camera, allowing you to more freely use faster shutter speeds and smaller apertures.

低 ISO 在戶外攝影時特別有用，陽光能提供充足的光線給你的相機，讓你更自由地使用更快的快門速度和較小的光圈。

ISO for indoor photography is largely situational.

室內攝影的 ISO 很大程度上取決於現場情況。

Depending on how well lit the area is, you may want to use higher ISO values.

根據場地的光線充足程度，你可能需要使用較高的 ISO 值。

Remember that if your subject is not moving, you can use a slower shutter speed or if you're okay with a shallower depth of field, use a larger aperture.

請記得，如果你的拍攝對象沒有移動，你可以使用較慢的快門速度；或者如果你不介意較淺的景深，可以使用較大的光圈。

Night photography, whether it be a moonlit photo shoot or astrophotography, will inevitably require high ISO values.

夜間攝影，無論是月光下的拍攝還是天文攝影，都不可避免地需要高 ISO 值。

This is where you need to experiment with your camera to find out how far you can push it without serious drawbacks.

這時候就需要你多嘗試你的相機，找出在不產生嚴重缺點的情況下，你能將它推到多高的極限。

ISO, while appearing to be a complicated subject, is actually very simple.

ISO 雖然聽起來很複雜，但其實非常簡單。

By exploring your camera's ISO profile and realizing when to use high and low ISOs, with an understanding of the principles of image noise and sensitivity, you will be able to directly improve the quality of your photos and be more comfortable with your camera.

透過探索相機的 ISO 設定，瞭解何時該用高 ISO 或低 ISO，並且理解影像雜訊和靈敏度的原理，你就能直接提升照片品質，也會對你的相機更加得心應手。

Stay subscribed to Apple Apps for more animations, which are released every month.

請持續訂閱 Apple Apps，我們每個月都會推出新的動畫。