Читать книгу Outdoor Photography онлайн

26 страница из 86

Sometimes the camera can freeze movement that the eye can’t follow; sometimes movement appears as a blur. Extremely slow movements, like those of the stars, can also be recorded although they appear static to the eye. All of these results depend on shutter speed.

Sensitivity

Well, of course photographers should be sensitive: sensitive to light, to mood, to the fact that your partner’s getting cramp balanced on that pinnacle waiting for a shaft of light… But that’s not what we’re talking about here. We’re talking about what used to be called film speed and is now called ISO sensitivity.

This is a measure of how readily the sensor reacts to light. A low ISO sensitivity rating means relatively bright light is needed to get a decent image. With a higher ISO rating, you can shoot with much less light

In the (good?) old days, we couldn’t change this at will. When you loaded a roll of film you had to keep shooting at the same ISO setting till the film was finished. You might load a slow film which was great for shooting landscapes in bright sunlight, then next day you’d run into all sorts of problems trying to shoot mountain bike action in a shady forest.