In the painting of Renaissance sfumato effect had been achieved by the softening of the outlines of figures and objects by recreating the surrounding light and air. The founder of this method was Leonardo da Vinci. This fuzzy technique requires from the painter a lot of time and patience because the effect is achieved by the overlay of many tiny strokes, enabling to render the subtle passages of tones, make the contours soft and blurred and create a lively interplay of lights and shadows.
Using this technique, photographer doesn`t aim to accurately convey the specific feature of the surrounding reality, but to force the viewer to rethink what he sees. This approach allows us to discover and convey to the audience the most important – the atmosphere and the mood. It should be noted, however, that such transmission of reality does not quite match the canons of the modern digital photography, in which in the first place are the sharpness and clarity of an image (sometimes excessive). Thus, the main feature of the photos in the technique of sfumato is contours softening and colour passages, color and light perspective: objects located in the foreground have warmer tones than the objects in the image depth, the background is always colder, brighter and more blurred.
It is possible to achieve such pattern of lights and shadows by directing the light source in the white ceiling, so that the diffused light falls on the subject. You may also use a soft-focus optics or special filters, which, by the way, can be easily made by yourself)) Outdoors a similar effect can be easily achieved on a cloudy and foggy weather.