Fisheye macro photography of herps using the Sigma 15mm f/2.8 lens
Articles | Macro photography tips
By Alejandro Arteaga. November 2017.
Meet the Sigma 15mm f/2.8 EX DG Diagonal Fisheye. This is a fisheye (i.e. ultra wide-angle lens that produces strong visual distortion) lens with 1:3.8 magnification that you can use to create close-up images of amphibians and reptiles while showing the environment where they live. You can also use it to present the animal you want to photograph in a creative and unusual eye-catching perspective that emphasizes its dimension against other elements in the image. You can even use it on white background photography of herps to give special importance to certain body parts of the subject, like the head or claws. However, the lens comes with its own drawbacks, like chromatic aberration, unusual angle of view, and slow focusing capabilities. For this reason, in this article, I present you 10 tips that you can use to harness the creative power of the Sigma 15mm f/2.8 lens while coping with its disadvantages.
1. Set the lens on minimum focusing distance (15 cm) and focus manually. The abilities of this lens to autofocus near its minimum focusing distance are extremely poor, and in fact, the lens often fails to "find" subjects that are 10–20 cm away from the front of the lens, which is the most appropriate distance to photograph frogs and small lizards. You can compensate for this by setting the lens on manual focus and choosing the focusing distance that will give you the desired magnification. For example, I usually set the distance on 15 cm unless the subject does not fit in the frame.
2. Try imagining the picture without the animal. If, without the subject, the overall composition still looks balanced, eye catching and interesting, then it makes sense to use the fisheye lens. If it does not, then try using another lens.
3. Photograph animals larger than 5 cm. Everything smaller than this is better photographed using a standard macro lens. Tiny frogs and some lizards fall in this category. When photographed using a fisheye macro, they appear as though they were "lost" in the frame.
4. Include lines. When you use the Sigma 15mm f/2.8 to photograph macro subjects like herps, you often come up with an image that includes a foreground and a background that are both in focus, but unlinked and competing for the attention of the observer. To solve this problem, you can include lines that lead the observer from the background to the subject. Examples are diagonal branches, streams, or groups of individual elements (like rocks or leaves) arranged in a linear pattern.
5. Use fill flash. In fisheye macro photography, you will rarely encounter a situation in which the subject is naturally more brightly lit that the background, especially if the background is a whole landscape. Therefore, if you want to bring attention to your subject, while also revealing its colors and details (like the head scales of the panther chameleon pictured above), it is crucial that you include at least a touch of fill flash during the exposure. You can do this by incorporating an off-camera, diffused flash unit that you can hand-hold right besides your lens to illuminate the parts of the subject that are in underexposed.
6. You don't always need a tripod. As a general rule of thumb, if you want to create sharp images while hand-holding your camera, you usually need to be shooting at a shutter speed of at least 1/nth of a second, where n equals your lens focal length (i.e. the distance between the lens and the image sensor when the subject is in focus). This is great news for the Sigma 15mm, because you can create sharp images while hand holding your camera using a shutter speed of 1/15th of a second, meaning you can create images of animals in dark understory situations where setting up a tripod may be complicated, like in the swamp shown in the picture of the anaconda above.
7. Be careful not to include your feet. You would be surprised how often you get them in your pictures while using a lens that, like the Sigma 15mm f/2.8 lens, has an angle of view of up to 180 degrees. In the picture of the chameleon above, my feet were just barely out of the frame.
8. Stay away from ambient salt and humidity. You may be thinking that this is true for all lenses, and you may be right. However, in my field experience, the Sigma 15mm f/2.8 lens is the most delicate lens that I have ever used, and in more than one occasion, it has stopped working due to humidity or ambient salt. One way to deal with this challenge is to always carry a plastic bag full of silica gel whenever you are using this lens in the field.
9. Shoot remotely. Remember that the minimum focusing distance of the Sigma 15mm f/2.8 lens is only 15 cm, which is well within the striking range for the majority of viper species. If you are trying to photograph venomous reptiles, like the bushmaster pictured above, mount your camera and lens on a tripod and trigger it remotely using a shutter release.
10. Always remember to remove chromatic aberration. If you want to have the images you create with the Sigma 15mm f/2.8 lens to be free of the extraneous cyan and magenta fringing along the edges of your subjects, you can remove it after the fact using any of the most popular image editing software out there. I use Adobe Camera RAW before I open the files in Photoshop.
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