Monday, July 28, 2014

Playing with multiple exposures

Out of my normal routine, this summer has been a blur of non-photography activities occasionally interrupted with mornings on Biscayne Bay, paddling around Chokoloskee or visiting Fairchild Gardens. Otherwise, I have been holed up at home which has given me lots of time to research, gather inspiration from other artists, and hatch new ideas.

Feeling antsy after the Biscayne Bay exhibit, I wanted something new in my photography and this has led me to using the tripod more often. That and the fact that I am suffering from carpel tunnel syndrome and trigger thumb (which has now evolved to trigger thumb and finger). It's my own fault. I tried using a monopod in the boat especially during those long hours of sitting in front of birds, but it is cumbersome and rendered useless with vertical shots. Having put up with on-again off-again numbness and discomfort in the hands and wrist, I need a new game plan. For the birds, I am going back to using the monopod (probably upgrade it to allow more leverage). But lately, I have been using the tripod on land more often. I am officially on another steep learning curve.

One of the techniques I have been exploring is multiple imaging, which basically requires use of a tripod. So far, multiple imaging for me comes in two versions. One version is the well known technique of stitching horizontally or vertically aligned images into one. Professionals that create these types of images rely on important (and expensive) hardware to get the job done right. But with my limited resources (a typical ballhead on the tripod), I can stitch some images together without noticeable parallax distortion. Here are a couple waterscapes, the first using the tripod (3 images) while out of the canoe and the second one handheld while in the canoe (2 images).

I've also tried the panoromic stitching with a common iguana. This reptile is a perfect multiple-image subject because it is long and stands still for long periods. The first shot is a horizontal pano of 3 images and the second one consists of 2 images stitched vertically.

The other multiple image technique that I am experimenting with is blending multiple focus points. This is something that macro photographers do quite well. However, it requires more work in the post-processing steps. I tried this out yesterday at Fairchild Gardens on a couple lubber grasshoppers (with their large size, they are great subjects for this practice!). I was using my 70-400mm lens and I shot at 250mm for one image and 400mm for another (the greater the focal length, the lower the DOF). I set the aperture at f11 as this offers good sharpness. Because of the nearness of the subject and the aperture chosen, the DOF would be limited to less than an inch at 400mm and about 2 inches at 250mm. This meant that when I spot focused on one part of the grasshopper, much of  the remaining grasshopper would remain out of focus.

To get the entire grasshopper in focus, I took two images to combine into one. Use of the tripod is essential because the images must be identical to the nth degree. In Photoshop, I used a layer mask to blend the two images by layering the sharpest portion of one image onto the other image. For instance, for the first image below, I focused on the top lubber's face for one image and the bottom lubber's midthigh on the other. With the layer mask, I layered the top lubber's head and upper thorax into the other image. It appeared to have worked!

There are plenty of tutorials from the experts on this method and I really could not recommend one specific one (I seem to go from one to another and pick out bits of information that work best for me), but here is one example.

Another use for multiple images includes a combination of multiple exposures and multiple focus points. Practicing indoors where you have natural light coming in through a window is great for this technique, as seen below. When I exposed and set my focus point for the inside, the outside area was overexposed and slightly out of focus. For the second image, I set the exposure for the outside (2 stops down with the shutter speed from 1/3 to 1/13 sec) and focused on the tree. In Photoshop, I used the layer masking technique above to blend the outside with the inside. The window frame serves as a rigid barrier, making the blending much easier.

I don't know where all this will go, but I am having fun so it does not matter. At the very least, I hope it inspires another photographer to try some new things. The possibilities are limitless.

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