Tutorial Tuesday: Bracketing

Bracketing is a very useful technique which photographers often use to capture a closer representation of the dynamic range within images. For example, if you’re shooting a landscape shot of the sea the sky may be very bright but the water very dull, so which area do you choose to expose for? If you correctly expose for the sky, you’ll lose detail in the shadows of the water, but if you expose correctly for the water the detail in the highlights of the sky will disappear instead. This makes it very difficult to decide on the correct shutter speed to capture the correct exposure over the whole scene. This is where the technique of bracketing comes in very useful. What this involves is repeatedly shooting the scene but using a different shutter speed for each shot to deliberately over-expose and under-expose, enabling you to capture detail within all areas of scene. Once this has been achieved Photoshop is used to stitch all these images together combining the various exposures to create one perfectly exposed image. Below is an example/tutorial to show you how this technique can be achieved.

Firstly, you need to take your shots, preferably with a tripod as it will be a lot easier to layer up your images in Photoshop later on. Here are two images below that I shot a while ago which demonstrate perfectly the need for this technique. I shot this flower in direct sunlight which resulted in a very bright, harsh light that was too much for the white areas in the petal yet not strong enough to capture the shadow detail in the pollen itself, the sun was positioned behind the flower slightly creating this ‘back-lighting’ effect. Being the main focus of this image, I need the pollen area of the flower to be perfectly lit.

Shutterspeed =1/160
©2013HannahBennett

    

Shutterspeed =1/400

©2013HannahBennett

If you feel the scene you are shooting needs bracketing then take one shot at the exposure your camera tells you to, then move the shutter speed by 1 stop to underexpose, and also 1  stop to over expose. For example, if your camera says to shoot at 1/160, to overexpose by 1 stop you’d then shoot at1/100, and to underexpose by 1 stop, you’d shoot at 1/320. For the example included in this post, I shot the overexposed image first at 1/160 then underexposed the second image by 2 stops and shot at 1/400. (This can be seen clearly in the pictures above)

©2013HannahBennett

To combine these two images, I opened them up into photoshop and placed the two layers on top of each other, then labelled them accordingly, whilst making sure that they were correctly positioned above one another. I then used the ‘Eraser Tool (E)’ whilst on the overexposed layer to remove the washed out petals, leaving behind the correctly exposed pollen area of the image.      

As you can see in the final picture below, I now have one perfectly exposed image, full of detail throughout the whole frame

©2013HannahBennett