![]() In a somewhat similar manner, high light-amplification in a digital camera is more likely to produce a noisy-looking image under low-light conditions. High-sensitivity film was more likely to produce a grainy image. Nowadays, with digital cameras we talk about the gain of the light-amplification system. In the days of film cameras, we talked about film sensitivity (“fast” film being more sensitive to light than “slow” film). the sensitivity of the image-capturing surface to light.The extreme case of a pinhole camera has a very tiny aperture with infinite depth of field (no need to focus at all), but captures very little light, so it needs a very well-lit scene, a long exposure, or a very sensitive image-capturing surface. A wider aperture increases the amount of light being captured without contributing to motion blur, but it reduces the depth of field. This is expressed, not as an actual distance measurement, but as a fraction of the focal length of the lens (loosely, distance between the lens and the image-capturing surface when the image is properly focused), written as f: thus, say, f/2.8 (“ f over 2.8”, not “ f 2.8”) is a larger number, hence representing a wider aperture, than f/8. the aperture - how wide the iris opening is. ![]() The longer this is, the more light is captured, but also the more likely the image is to pick up motion blur from moving objects.
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