ISO Settings: How to Choose the Right One?
In this topic, we’ll discuss an essential question: What is the ideal ISO setting?
The biggest difference between the two images below lies in the background. Under the same lighting conditions, what exactly caused this variation? Keep reading until the end to gain a deeper understanding.
1. ISO, Aperture, and Shutter Speed Work Together
These three settings are always interconnected and never fixed. When capturing fast-moving subjects (such as in this case), the key is to maintain a shutter speed between 1/1000 – 1/2000 to freeze motion effectively. Additionally, as this shot was taken using a 100-400mm telephoto lens, a high shutter speed is necessary to minimize camera shake.
2. What About Aperture in This Case?
If we use a wide aperture, the moving subject is more likely to fall out of focus. Moreover, due to equipment limitations, the minimum aperture is already f/5.6 or f/6.3, leaving us with only one adjustable element: ISO (both images presented are unedited, straight out of the camera).
3. The Role of ISO: Why Does It Matter?
- Higher ISO allows for a faster shutter speed, enabling us to freeze motion effectively.
- Increasing ISO helps to close down the aperture while maintaining adequate shutter speed.
- Adjusting ISO influences background exposure, giving us greater control over lighting:
- In the first image (ISO 250, left side), the darker areas remain significantly underexposed.
- In the second image (ISO 400, right side), details in the shadows are more visible.
- In complex lighting conditions (mixed bright and dark areas), ISO adjustments impact different parts of the frame. Raising ISO brightens the background, while lowering ISO darkens it—a useful technique to control exposure when aperture and shutter speed must remain unchanged.
Key Takeaway
ISO settings should not be dictated solely by the lighting conditions (e.g., low ISO for bright scenes and high ISO for dark environments). Instead, always consider your intended outcome for the image. Understanding how ISO interacts with shutter speed and aperture will help you achieve the desired exposure and creative effect.
We hope this guide provides valuable insights for your photography journey!
