Photo
Exposure metering
First zone – absolutely dark. These are those parts of image where you needn’t any details.
Second zone – it is also black but slightly lighter than the first one. Details can be indiscernible here.
Third zone – it is lighter and reproduces slightly visible details. Examples of this zone in the photo are black velvet, bridegroom suit, bark of trees in the shadow…
Fourth zone – dark colours of black clothes, hair, trees, shadowed foliage, wet asphalt.
Fifth zone – shadow on a dry asphalt, leaves on the trees, deep suntan on the skin.
Sixth zone – middle-grey colour. It reflects approximately 18 % of incident light. Green grass, red brick, dry asphalt in the shadow at defused by the clouds sunshine. Middle-grey object conforms to this zone of Adams scale. Such object serves as a standard for all exposure meters, both stand-alone and onboard in camera. This is the point from which we must start analyzing the object of shooting. Try to remember the objects which reflect light in the same way as the middle-grey card as much as possible. You can buy such cards in a photoshop or make them on your own. I always carry a piece of grey cloth with me. The cloth is very convenient for my work: it is absolutely mat, it neither flashes nor becomes creased, it doesn’t tear and easily takes the shape of the object on which you lay it down. Thus, it is lightened at the same angle as the object you want to shoot.
Seventh zone – cloudless blue sky, a newspaper sheet.
Eighth zone – barely perceptible details against light background, light-gray, yellowish, cream-coloured, silvery components, snow lighted with a side sunshine.
Ninth zone – almost absolutely white colour: a wedding dress with dull apparel.
Tenth zone – absolutely white colour: glares of metal surface, white background intensively brightened in a studio, bright sources of light.
Each zone of the scale is exactly two times lighter or darker that the neighbour zone. It’s enough to change the aperture or exposure in one grade in order to shift to one zone of the scale.
7. Grey scale. It reflects 18% of incident light. You may copy and print it. And then use it for metering. You can use it provided that your monitor screen and printer are calibrated.
Now when you know what zone of the grey Adams scale the main part of your shot belongs to, you can correct the “silly” exposure meter of your camera. For example, if you want the snow texture to be well discernible in a picture of winter scenery, remember that light subjects belong to the eighth zone of the scale. This zone is two grades lighter than middle-grey zone. When measuring the light reflected by snow any even the most precise camera will try to attribute snow to the sixth zone: it will be grey in the photo. I order to save the whiteness of snow, you must let pass four times more light to the film than it is recommended by automatic camera. Open aperture or prolong exposure in two grades. Analyse every subject of shooting in such way and then you won’t be disappointed by the result.
How to measure light
At first sight the question is simple. Modern cameras carry out this procedure precisely. Reflex cameras measure light straight through the lens; thus, their reading is affected only by the light which passes to the film. They make allowance of the light absorbed by the filter-converters and other obstacles that can be constructed on the lens carrier by the photographer. But it only seems to be simple. Exposure meter can measure only the light reflected by the object of shooting. This doesn’t guarantee correctness of exposure.
In most cases you can make a precise measure by metering the incident light by means of a separate exposure meter. Point the diffusion sheet of the device to the camera and it will indicate correct exposure. Grey colours of the photograph will strictly agree with the sixth middle-grey zone of Adams scale. Such measuring guarantees nearly 100% high quality of the negative for black-and-white colour negative films.
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