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light values

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Light values for photography and exposure

see also:

Digital exposure using the histogram method:

Light values:

The S+L = A+T exposure system:

Examples of light values:

Light value (approx.)

add 5 for EV at ISO100

Example ambient lighting scenes
10 bright sunlight
9 subjects backlit by sun with light background to give a silhouette (try 7-10LV); photos of the moon +/- 1stops;
7 outdoor shade (light from midday blue sky) 
6 overcast sky (6.5LV ~1000lumen/sq.m); subjects backlit by sun with dark background (try 5.5-7LV) - may need a warming filter;
5 light from blue sky at sunset; crescent moon; ie. landscapes immediately after sunset;
4 sports ground night lighting (3.5-4 eg. ISO 3200, f/2.8, 1/1600th sec); indoor lighting (3-5); Paris' Dome Church ceiling in daylight; Church stained glass window in daylight; twilight 30-45min after sunset of mid-toned subject - bracket +/- 2 fstops; neon lights; 
3 under a 300W reading lamp
2 office lighting
1 average living room lighting; heavy cloud, rain (0.6LV ~100lumen/sq.m); slit lamp for corneal flourescein; 
0 the Louvre paintings (most are -1 to +2, eg. Mona Lisa 0.5, although some are very dimly lit at -2.5 to -2)
-1 night scenes of street lighting on buildings/streets (-2.5 to +0.5 eg. 1/15th sec, ISO 2500, f/4); twilight (~10lumen/sq.m)

St Peter's Basilica interior (1/15th sec: 1600ISO, f/4 if using Canon or 400ISO, f/2 if using Olympus)

-2 light from a candle at 1 foot = 1 foot-candle; church cathedral interiors (eg. Notre Dame -3 to -1); fireworks;
-3 lightning +/- 2 stops;
-4 light from a candle at 2 feet = 0.25 foot-candle; distant view of city skyline lights; 
-5 light from a candle at 1 meter = 1 lumen/sqm = 1 meter-candle = 0.09 foot-candle; deep twilight;
-7 night scene lit by full moon overhead (~0.27lumen/sq.m); photo of bright stars (~0.0001lumen/sq.m for -1.4 magnitude)
-11 photo of deep sky objects such as comet tails, nebulae (~0.0000001lumen/sq.m for 6th magnitude objects) - see astrophotography

Zone system for reflective light metering:

Zone Reflectance % F-stops Examples
IX 95% +4 snow
VIII 80% +3 off white; show some details;
VII 70% +2 light gray; shows distinct texture.
VI 35% +1 Caucasian skin
V 18% 0 mid-gray = setting for light meters
IV 16% -1 brown skin
III 13% -2 black skin; shows distinct texture in prints
II 9% -3 very black skin; shows some details;
I 2% -4 black velvet; no details;

A few more concepts:

Very brief duration light sources:

What is the true ISO?:


Reciprocity failure compensation for most films:

Dealing with high contrast scenes: