Combining images for depth of field
One of the many great options digital image has brought to photographers
With this image I combined in-field techniques with some Photoshop techniques.
This scene of Upper Horsetail Falls in Oregon’s Columbia River Gorge, photographed with a 12-24mm lens at 16mm mounted on a Nikon D300, posed some dilemmas. I wanted a long shutter speed to blur the waterfall and stream, yet I needed a fast shutter speed to stop the motion of the wind-blown foreground. To solve this, I took three shots focused at different points in the scene and then combined them in Photoshop.
It's extremely important that the camera position does not change between exposures. So be sure you figure out the exposures ahead of time and then lock the camera securely on the tripod head.
The first part was easy. I took two shots at ISO 200 (for highest quality) focusing first on the background and then on the trees in the middle. These shots were at a f/16 and at about 1 second.
The foreground needed to be shot at a faster shutter speed, around 1/60 second, to stop the motion of the Bleeding Heart in the foreground. This meant a relatively wide aperture. At ISO 200 the shutter speed was still too slow. ISO 640 allowed me to shoot 1/50 second at f/5. This was enough to stop the wind motion of the foreground.
As with nearly all waterfall/stream/forest pictures, a polarizer really helps with cutting the glare from rocks or leaves, and this situation was no different. With a regular polarizer, I would have had to use an ISO of 1000 to achieve the same shutter speed and aperture combination for the foreground image. But with my Singh-Ray LB Warming Polarizer, which is 2/3 stop faster than a regular polarizer, I was able to use ISO 640. On the D300 there’s not a horrible amount of noise at ISO 640, definitely less than there would be at ISO 1000. Using the LB Warming Polarizer I was able to shoot at an ISO that gave me the highest possible image quality given the situation.
After getting the images into the computer it was just a matter of layering one on top of the other and masking out the un-needed parts of each. (for more on layering the separate images, see my exposure blending tutorial).
Since focus is being changed with each exposure, this means that the composition is also slightly changed and each layer will be slightly "off" in alignment. You'll need to use the "Auto Align Layers" command (Edit>Auto Align Layers) before you start masking.
I also used Imagenomic’s Noiseware for some noise reduction on the foreground layer. To finish up I cloned out the person under the waterfall and then used the "Stamp Visible" command (Control-Alt-Shift-E) to create a layer that is a flattened version of all the visible layers. I used this layer as a final tune up to adjust colors and bring out some details in the shadows adjustment layers.
The tricky part is in creating the masks and wrapping your head around using more than one layer.
Another way to (sort of) accomplish this in Photoshop is to have Photoshop automatically align and blend the layers. I've found this technique to be not as reliable for landscape images as it can be for close ups. But if you want to try it, be sure to read my article about automatic focus blending in Photoshop.
Since the time I originally put this image together (and when I wrote the original version of this article) some pretty great software has come out that makes this process so much easier. I've since reprocessed these sets of images using Zerene Stacker. Not only were the results just as good as doing it all manually, it took a fraction of the time. And instead of prepping and finishing off the image in Photoshop, I did it all in Lightroom, including the noise reduction for the foreground image and using the Spot Removal tool for the person under the waterfall and the Vibrance, Blacks, and Shadows slider for some subtle color and contrast touches.