Jim Gollan @ OCA Landscape: Clouds and sky (24)

Requirement

6 to 12 images

Purpose

To explore the role that sky and clouds can play in composition
To practice managing exposure in different light conditions

Technical learning

In summary, clouds:

are the most visible component of weather
are significant in defining landscape mood
are the most important element in creating the quality of daylight
come in several types (nimbus, cumulus, etc) and even more permutations
present a challenge to the dynamic range of the camera sensor

Working beyond the limits of your camera's dynamic range - measures

RAW: shoot RAW, expose for the sky, lighten the land in post-production

Bracketing: take reflected light readings of highlights and shadows separately, bracket images across the gap in exposure between the two, blend in post-production in PS or a HDR application

ND Grad Filter: as with meter readings for bracketing, but use then use a ND Grad Filter of sufficient strength to compress brightness of sky and land. (0.3 = 1 stop, 0.6 = 2 stops, etc)

Crude reckoner of exposure change between cloud conditions (NB not between land and sky in those conditions)

Heavily overcast - baseline

Moderately overcast - + 1 stop

Cloudy, but bright - + 2 stops

Thin, high cloud - + 2.5 stops

Heavy haze - + 3 stops

Clear sky - + 4 stops

Overcast conditions (i.e. the sun is not visible)

On the one hand, soft light produces generally shadowless scenes (except where one object casts a shadow on a close neighbour) and so drains the landscape of 'expression'. It reduces modelling of shapes, perspective and texture so making the image look flat.
On the other hand, soft light has 2 important uses: (a) it can clarify the detail of complex subjects, otherwise masked by shadows thrown in brighter conditions, and (b) it enables reflective surfaces to produce clearer images (i.e. without the specular highlights and glare from the sun).
Nevertheless, overcast conditions increase the contrast of tones between sky and land (compared to clear skies, the brightness of the sky falls less than that of the land). Consequently, subject to the dynamic range of your camera, if the land is exposed correctly, the sky will be burnt-out.

Broken cloud

Often creates interesting, even dramatic lighting, especially when the weather is changing
Most unpredictable environment, however, particularly when (a) the sky has different layers or types of clouds, (b) conditions are windy and (c) when weather fronts collide
Must be prepared to react quickly to changing conditions

Clear skies