Bracketing

Under a bracketing means a graded series of exposures in photography to the object extent of a template or a subject precisely as possible to the printing range to transmit a photographic material or cast. The same motif is shown several times with different exposure settings (for example +/- half or a third of an aperture stop ).

The English term bracketing has a broader meaning and is to be understood in the sense of a series of photos by varying one or more recording parameters, while the camera and object remain static. The varied parameters can be, for example, various exposure parameters, the white balance , the sensitivity setting or the distance setting.

Modern camera systems accept such series features some automatic (Engl. Auto bracketing , Autobracketing ). Depending on the changed parameters, the recordings can then be merged (examples: HDR, focus stacking, see below).

Bracketing

Bracketing (Engl. Exposure bracketing ) can both come when photographing itself and during the creation of magnifications in the photo lab used.

The change in exposure usually takes place via the duration of the exposure time , but can also be controlled via the f-number or, in the case of digital cameras, via the change in the sensitivity setting. The figure on the right shows a series of exposures that was created by the natural light of dawn.

Modern cameras can automatically create series of exposures for mostly three, five or seven images. Manufacturers usually use the term Auto Exposure Bracketing ( AEB ) to refer to this.

Practical examples

A series of exposures in which a moving object can be seen in the individual images.

Bracketing is used in photography when the subject has a very high dynamic range . A series of exposures in combination with suitable software to merge the individual photos can help in such cases to reproduce a high dynamic range of an object. An exposure series is created from the (stationary) subject in such a way that each area of the subject is well exposed on at least one of the images in the series. Subsequently, an HDR image can be created from the individual images by the camera processor or on the computer , which depicts a large dynamic range (see HDRI generation from exposure series ).

In the classic photo laboratory , exposure series are used and evaluated in the form of test strips , among other things . Exposure series are possible both on the camera side during the exposure and later during positive development. Slide films have a lower exposure latitude than negative films; they must therefore be exposed more precisely, and in case of doubt, a series of exposures is recommended if the object has a high contrast range. When shooting at night on conventional film, it may not be possible to determine the exact exposure time due to the Schwarzschild effect . Here, too, you can achieve a useful result by trying out a series of exposures.

In repro photography , exposure series are created in order to obtain at least one reproduction that corresponds as closely as possible to the original. This is necessary because, on the one hand, the exposure measurement does not always lead to exact results due to factors such as the extension length or any filters used , on the other hand, because the reprofilms that are often used work extremely hard.

Flash bracketing

Under a flash exposure series, engl. Flash Exposure Bracketing ( FEB for short ) is a gradation with regard to the flash exposure intensity. Similar to the exposure time, corrections can be made on higher quality cameras and flash units.

White balance continuous shooting

Some digital cameras have a white balance continuous shooting function. Here, while maintaining the same exposure time, several images are taken with a comparison to different color temperatures . The English expression for this is White Balance Bracketing ( WBB for short ).

Sensitivity series recording

Engl. ISO bracketing . The exposure time and aperture remain constant while the sensitivity setting is varied from shot to shot.

Distance setting series recording

Engl. Focus bracketing . The exposure parameters (exposure time, aperture, sensitivity setting (ISO value)) remain constant, while the distance setting is varied manually or automatically by the camera system according to specified parameters. Such a series of recordings can, for. B. can be used for focus stacking .