Bracketing Exposure. Castleford Camera Club.
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Inphotography, bracketing is the general technique of taking several shots of the same subject using different camera settings. Bracketing is useful and often recommended in situations that make it difficult to obtain a satisfactory image with a single shot, especially when a small variation in exposure parameters has a comparatively large effect on the resulting image. Autobracketing is automatic bracketing by using a setting on the camera to take several bracketed shots (in contrast to the photographer altering the settings by hand between each shot).
- 4 stops
- 2 stops
As can be seen in the previous slide, moving exposure minus by 2 or 4 stops darkens the photo dramatically. In the following slide the effect is lightened greatly by going + by 2 & 4 stops, this has caused some over exposure, even burn out of the highlights.
+ 2 stops
+ 4 stops
To use the Auto Bracket function on your camera can help achieve images lost by not having the correct setting at the time of releasing the shutter.
A typical example is whereby the lighting and/or conditions are constantly changing, ie: Sunsets &/or Sunrise.
Whilst you set the exposure/settings then check the results WILL cost you time and most possibly cost you the photo, bracketing your exposures will help you achieve the photo of 'the moment'.
Also known as hedging your bets. (Ensuring one out of 3 shots is perfect.
As previously mentioned, Auto Exposure Bracketing (AEB) allows you to take 3 images of different exposures without having to alter any settings between shots/frames. Most DSLR's allow sequential shots of +/- 3 stops from base exposure. There are some cameras that allow up to 5 stops of AEB.
This function works in Aperture, Shutter, Program & Manual modes.
The best method is to use a tripod and a remote release/timer so as to capture the very same image. Set the focus then switch to manual, the last thing you want is the lens 'hunting' for something to 'lock' onto.
You access the AEB function through your menu screen. Use the input dial/button to select just how many stops you need the bracket to cover.
Exit the menu screen.
Set up the shot, tripod, focus and press the shutter button 3 times or use a shutter release to capture the bracket.
Some camera allow the user to press the shutter button once & it will take the 3 shots automatically.
To take exposure bracketing a step further, I will explain EV (Exposure Valuation) some times known as Exposure Compensation. This works in conjunction with exposure bracketing.
This is the simplest exposure override method & is found on every DSLR, it very easy to use adjusting exposure by set increments of 1/3 or ½ stops (depending on the camera). Applying a positive + value increases exposure therefore lightening the image/s. Hence a negative – value decreases & darkens the image/s.
The amount set is usually shown on the LCD/Viewfinder or top window.
How the camera applies exposure compensation (EV) will depend on the exposure mode used.
In Aperture Priority it is the shutter speed that changes.
In Shutter Priority it is the aperture that alters.
In Program the camera alters either variable depending on the light & risk of camera shake.
The general rule is: If the subject/scene is very light, has a dominant light area the camera MAY underexpose so, dial in (+) value.
If the subject is dark or dominated by a very dark area, dial in (-) value as the camera is likely to overexpose.
Using the EV Exposure Compensation can help, provide a method to gain a correct exposure.
To bring this to an end lets imagine you shoot a snow scene, do you apply ½, 1 + value to prevent over exposure?
Set the camera +1.5EV, Exposure Compensation then in AEB (Auto Exposure Bracketing) set +/-0.5EV, when the sequence is shot the result will be a set of 3 images at +1, +1.5 and +2EV.
Predominantly the main use is to capture images to produce High Dynamic Range (HDR) images. Make sure a tripod is used to prevent movement.
Lastly.........if anyone is familiar with these techniques please feel free to help others.
I hope this has been enjoyable and of use to you. If just one person has understood then brilliant.