Lowered light levels can often be dealt with simply by upping the ISO setting, but consider ﬁrst whether the scene should actually look darker than average. As rain begins to pelt down from darkgrey clouds, you can best preserve the sensation by making sure that the clouds and everything else are indeed dark in the image, and not try to brighten them to make it look as if it's not such a bad day.
Quite the opposite happens if the sun breaks through to light up the foreground or middle ground, and the contrast shoots up between lit landscape and dark sky. This combination is always dramatic, and order to capture it you should avoid over-exposure at all costs. Dark skies can radically alter the lighting of a picture, not just in landscape photography. A facade of a building suddenly illuminated by the sun against a dark sky can look very dramatic indeed,as can a mountain ridge suddenly highlighted in otherwise gloomy conditions, or a ﬁeld of rice glowing bright green against a dark grey backdrop. You might encounter these conditions spontaneously, but you may also have to wait. You may also have to run so that you are in the right place at the right time — before the sun goes in again. And again you might consider bracketing so as not to lose the moment.
All cameras use automatic exposure by default, and the simpler ones offer few possibilities to over- ride this. Nevertheless, automatic exposure systems are not yet content-aware, and any unfamiliar light- ing conditions call for judgment. The saving grace with digital photography retouch is that you have some lat- itude when processing the image, with the possibilities for recovering mistakes, as we show in the At Home section. Nevertheless, three basic considerations will get you through most exposure issues to do with lighting.
First, how bright or dark should the scene be? This may not seem obvious until you come across certain conditions, like snow, a bright sandy beach or a village nestled in a valley at dusk, as the lights begin to come on. lust remember that the cameras exposure system will always try to give you an av- erage mid-tone. While this perfectly suits most scenes, it would render a snowscape a dirty grey, a bright tropical beach too dark, and fading dusk unnaturally light.