Leafy Sea Dragon at the MN Zoo
Shooting in an public aquarium environment can be difficult. Usually flash and tripods are, either forbidden, or too encumbering to use in the heavily-trafficked areas. Aquariums themselves pose their own unique set of problems as well:
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Reflections onto the surface of the glass/acrylic of lights, people etc.
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Unusual lighting spectrums used to promote the health of the animals in the aquarium
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Distortion of the occupants by refraction around edges, curved surfaces and the chromatic aberrations introduced by the non-optical quality glass/acrylic
Given these constraints and the low light levels present, this shoot was a challenge.
I showed up at the zoo with a Canon 5DMKII with a Canon 50mm F1.8 lens. I knew that the wider lens I used, the more danger of introducing some wicked CA into the shot, so I wanted to keep the angle of view tighter to avoid some exotic acrylic fringing. The focal length was sufficient to allow me to isolate the depth of field, effectively eliminating details from the front and back glass from the shot but not so razor-thin I couldn’t get the bulk of the creature in reasonable focus.
Unprocessed Before Image
Exposed at 1/160th at F8 at ISO 1600, the ‘before’ shot, shown above had some problems. First, there was no sufficiently non-descript background against which to shoot. I was stuck with distractions no matter where the Sea Dragon hovered. In addition, there was no position I could adopt that would prevent some of the room’s lighting from intruding. This was the best I could manage in-camera. There is a small plastic plant frond in the foreground, a tube or wire, across the black background of the tank and a nasty spot light reflection at the top. There is also a barely-discernible red reflection under the Sea Dragon’s jaw.
I almost left White Balance out of the equation but it turned out to be a major issue. As I said, the lighting was very unusual. Shooting in RAW, I knew I could set my white balance later but I would need a reference for setting this white balance. Fortunately, I considered the problem at the shoot instead of later in post-production. The only item in the aquarium that looked remotely neutral was the crushed coral sand substrate. I snapped a shot of it to use as a reference for later in white balancing the entire group of shots. As it turned out the White Balance was really out there and it took a very radical slide to the 30,000° K range to bring the whites into line. Even then-the bulbs weren’t necessarily broadcasting full-spectrum so I was still guessing at some of the colors.
From there, it was post production in Lightroom 3.0 Public Beta 2 to clean up noise, sharpen and adjust the colors. The new version of Lightroom works wonders with noise in high-ISO images. Background and foreground distractions were brushed out with negative exposure.
Rikk Flohr © 2010
nice, very interesting , thanks u