Did I travel to Mars for this shot? Nope,,, So where does one find such a creature as this? The Giant Isopod “genus Bathynomus; B. giganteus” is a deep water ocean crustacean. If you saw the whole body (sorry, I only photographed the head) you would see that it looks a lot like a big ‘ol 18″ rolly polely (pill bug, sow bug)…. You know the ones. You used to play with them as a kid and make them roll into a little ball.
Ok, back to the photo. I did not travel to the ocean depth for this. I photographed it at the Westminster Butterfly Pavilion. In addition to butterflies of course, they also have various other insects and some salt water tanks. This guy is new there, just arrived last Fall.
How did I take this Photograph?
To get a quality image of a critter like this one in a tank takes a few extra steps. There are some issues that must be dealt with before snapping your photo.
Reflections: A dark tank in a lit room equals, reflections. We don’t want to see everything else in the room in front of our pretty model. Since we cannot turn off the lighting in the public room, I simply put my camera on timer and then stood in front of the tank and held a jacket in front of as much of the glass as possible blocking the majority of ambient lighting from the room.
Depth of Field: In order to capture the interesting details of the Giant Isopod I had to shoot at relatively high magnification (focal length – 120mm and close distance – approx 24 inches). Not full macro, but nevertheless close enough that even an F/16 aperture only provides about 2 inches of sharpness. If you don’t understand the relationship between focal length, distance and depth of field please visit this tutorial on Depth of Field.
- Issue 1: As this creature is a deep water species it cannot tolerate bright light and so the tank is quit dark. As such a larger f/stop would have driven my exposure time to several minutes. That won’t work since the ebb/flow of the tank water would cause blurring of the subject.
- Issue 2: Even if possible an f/stop over f/16 would have introduced far more diffraction than I would want for a detail based image like this. Along that same vein even f/16 is not the best choice. f/4-8 is the sweet spot of my lens.
In order to resolve both these issues I used a macro technique called “focus stacking” whereby I take multiple photos at a relatively low f/stop (in this case f/4). Each frame has a very shallow depth of field (about 1/4 inch). Additionally each frame is focused at a slightly different location along the body of the subject. From front to back I shot about 24 images (more than actually necessary to ensure I don’t miss any part of the subject).
Once the images are back home I made a few tweaks to one image in Lightroom > sync those changes to the rest of the images. Note that due to our next step you do NOT want to do any sharpening or noise reduction on the images.
Stacking: The developed images are then imported into Helicon Focus (a focus stacking program) which combines only the sharp pixels from each of the images in the series. For those familiar with the program I used “method C”.
The final output image can then be sharpened and any needed noise reduction done.
WANT TO LEARN MORE ABOUT MACRO PHOTOGRAPHY?
Join my upcoming Butterfly Macro Photography Workshop held at the Westminster Butterfly Pavilion.
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