A Simple How to Technique

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Photo-realistic High Dynamic Range image do click on the photo for the larger view. A recent post: Subtle HDR-No Whacked Out Colors Here details a how to for a simple HDR. This post will deal mostly with manually blending or stitching 2 sets of HDR’s in Photoshop.

Always have the DSLR on a sturdy tripod and have the remote switch shutter release plugged into the DSLR (after DSLR is on the tripod to avoid tangled up wires). From the top LCD on the DSLR, dial in for AEB (Auto Exposure Bracketing). For Canon shooters that is just 3 exposures: -1, 0, +1. Try -2, 0, +2 for different results and choose high speed shooting mode again from the top menu so the 3 exposures will fire off without a hitch.

Now shoot the heck out of the landscape but on’t take too much time fiddling with the next 3 exposures. When the sun sets into the horizon color ranges vary greatly within a few minutes. Shooting fast can still get you different colors from the first set of exposures but they can be corrected in RAW to get the same tones.

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Shoot 3 exposure of bottom half first as color and light will affect this part of the photo more than the sky. It is also easier to deal with the colors in the sky later on in post if colors do not match the bottom half.

Next, gently adjust your tripod and shift up-this is where live view (EOS 50D, 60D, 7D, 5D) comes in handy. Shoot the next 3 exposures to overlap the first set of exposures. Just include about 10-20% of what is on the horizon to keep as guide when manually stitching later on and for reference to color changes.

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Now that the 2 sets of 3 exposures are finished, grab a cup of coffee, a piece of pie and relax. Take in the beautiful view at hand and remember no 2 sunset scenes are ever alike.

Next put each set of exposures into your favorite HDR processing software (I use either Photomatix or Photoshop CS5) and process the 2 sets separately. Then save them as TIF files to be worked on later. Once the 2 sets of HDR images are ready open them up in Photoshop, stack them in separate layers, add a masking layer (to sky set) and align the sky layer to the bottom layer. The most accurate way to do this is set opacity on the top image at 50% and align using the selection tool (use the horizon/buildings as reference). Zoom in at 100% to make sure the buildings and horizon are aligned.

Once the 2 HDR layers are aligned carefully brush away the part of the horizon on the sky set to show the bottom (city shot) photo. The 2 layers will look seamless if a soft brush preset at 50% preset is used. Brush strokes should start from one end of the image to the next (left to right-right to left). This technique is easy to do once a few trial and error brush strokes are done. Don’t be disappointed by the first try. I had to work my way through this process all on my lonesome in 2007-as evident in the many holes in the wall punched through out of frustration-ok, this part isn’t true but that’s sort of how it felt.

One of the most important features in Photoshop is control Z. This shortcut is an ‘undo’ if a mistake is made.

Capturing the 3 exposures are the easiest part of this exercise. The manual blending brush strokes are the most labor intensive of the process (depending on detail of the horizon). Once you achieve your desired look all it takes is some adjustments in overall color to bring the 2 sets together.

Twilight at 6:30 pm captured on Canon EOS 50D at 24mm, ISO 125, tripod with ball head and Canon RS-80N3 Remote Switch (cheapest of the bunch).