If lighting is extreme, which iris should be used?

• A. Fixed iris
• B. Auto iris
• C. Manual iris
• D. Adjustable manual iris

Answer: (D)

Managing exposure in extreme lighting hinges on having precise control over how much light enters the camera, which is governed by the iris. The iris acts like a compact adjustable hole: opening wider lets in more light for brighter scenes, while closing it down reduces light to prevent overexposure and to maintain detail.

A fixed iris is stuck at one size, so it can’t adapt to very bright or very dark conditions—you either blow out highlights or lose detail in shadows. An auto iris tries to compensate, but automatic adjustments can be fooled by glare, backlight, or high-contrast areas, leading to unstable exposure. A manual iris lets you set the aperture, but if you can’t change it quickly, you may still struggle as lighting shifts.

An adjustable manual iris gives you both control and flexibility: you can select a specific aperture that yields the right brightness for the scene and adjust it as conditions change, while also dialing in the depth of field you need. This combination makes it the most reliable choice when lighting is extreme.