EV | Panorama Palace

AEB – Auto Exposure Bracketing is a functionality present in photographic cameras for many years. This feature makes N exposures with the “distance” to the middle of EV’s preconfigured. This distance can be of exposure value, apperture or with digital cameras, ISO.

Many years ago, while using film cameras, I received a mail with some thoughts on photography and one of which was “Use bracket. Film is cheaper than a new trip. “If the roll time it was advised, imagine the digital time! Memory card is much cheaper than a new journey.

Bracketing idea is to prevent photo exposure errors caused by automatic or manual settings.

If, for example, the amplitude of the image is 14 EV’s (-7 to +7), depending on the scene, we can bracket [-2.0 + 2], ie, from -9 to +5 (getting good exposure for lights sun and sky blue), -7 to +7 (normal exposure) to +9 -5 (good exposure in shadows) regarding automatic settings or M mode.

At home, calmly, we look at the histogram and we select the photo that best corresponds to our idea for the scene. If we choose the darker able to regain some shadows but we have all the detail in the highlights. If we choose to have clearer detail in the shadows but possibly the Sun will be a larger ball. It is a matter of personal taste.

Depending on the situation it may be desirable that the driving mode – shooting mode is

– Burst. Takes 3 pictures then the maximum speed of the camera fps shooting. The N pictures are made quickly (at camera fps) and can be used in any subject in motion during the day.
– With timer. Can be with or without mirror / lockup in case it is essential that the machine does not shake (of course, a tripod). If the camera is mirrorless has no mirror lockup.

After shooting AEB we can always produce an HDR image stretching the amplitude of various light images to an image much “richer” in light amplitude.

The exposure triangle shows, graphically, the impact and the compensation that must be made for each of the parameters to ensure an image with the desired exposure. If you move one side towards “less light” one of the other sides must move towards “more light”.

Note that I said “desired exposure” and not “correct exposure” as “correct exposure” might mean that the image has no dark areas without detail or burnt areas and, in some cases, may even be the intention.

When reading the triangle can be seen that, for example, to increase the F (reducing the amount of light passing through the lens and improve DOF) one has to increase exposure and / or increase the ISO (increasing the grain on the picture . If the idea is to freeze the motion shortening the exposure compensation would be to decrease the F (increasing the amount of light passing through the lens and decrease DOF) and / or increase the ISO (increasing the grain in the photograph).

We can observe the variation of the impacts of any of the parameters on display can be seen on the scale of “exposure compensation” ranging typically from -2 to +2 stop’s.

By placing the camera in M mode carry out a measurement (press the photo button halfway). Then adjust the speed so the dot stays in the middle of the scale (0). Increase the ISO to double, measure, see what you have to change to replace the measurement in (0).