Backlight is a situation used in photography, especially name for a light source, which is located directly in or near the design direction.
Back light that falls into the lens of a camera, has a number of effects on the resulting image:
- If the light from a bright light source directly onto the lens, so a series of images of the aperture will be (usually round or hexagonal ) shown on the image. They are caused by unwanted reflections inside the camera and are depending on the quality of the lens and the reflections within the camera body less pronounced. This effect can usually be effectively reduced with lens hoods, in some images such reflections are also used as a means of expression and caused artificially by filters.
- If direct light source obscured by any part of the motive, this appears too dark when automatic exposure metering prior to a properly lit background. Therefore, one should use in backlit portraits always additional light sources (such as a mirror or a flash light) when the face should be discoverable. This is even with high quality cameras that detect the backlight situations, necessary, otherwise the background will be overexposed.
- In addition to this light-dark contrast color contrasts are attenuated, so that dull color images can emerge. Also contributes to the so-called fogging of the lenses in backlit conditions.
- Transparent or partially transparent bright objects light up against the light, while structures can be clearly that remain hidden in reflected light from the object surface.
Automatic programs from cameras rarely work satisfactorily for backlit subjects. The automatically exposed images are usually too dark when the light source (s ) are in the range. If the camera has allowed, multiple spot metering on image important areas, the calculation of a mean value and manually adjust the camera recommends.
- Problems for backlit subjects
Extremely reduced colors, even on directly irradiated by the sun faces on the Hohensyburgstraße
Contrast -reducing reflections and refractions in direct backlight
The sun shining through a sheet suggests no green leaf surface.
Against the light flashing Yucca flowers
Screening of leaves: very high contrasts
Measurement of unwanted backlight
The adverse effect of back light in photographic images based on light sources outside the recorded image angle. It is possible by measurement to determine the influence of such back-light as stray light. These include, for example, a dark object to be photographed while positioned a bright light source outside the image field and directed into the lens. In the ideal case, the light beam of this light source are directed not affect the recorded image, but, in practice, within the lens and the camera body, these light rays reflected or diffused or diffracted. The two figures on the right illustrate experimental design and an image result in relatively strong backlighting effect without the use of a lens hood.