Photographing Scorpions under Blacklight

[skinheaddave]

Scorpions are interesting for a variety of reasons, not the least of which is their ability to fluoresce (glow) when exposed to ultraviolet light from “blacklights.” The effect of UV light on a scorpion is stunning, and photographs of this phenomenon can be among the nicest images captured by the scorpion enthusiast. Unfortunately, capturing good quality images of scorpions fluorescing is not a simple point-and-shoot affair. Taking such photographs requires at least a basic understanding of photographic principles – particularly as they apply to macro and low-light photography. I hope that this article will help people to take better pictures of fluorescing scorpions.

The Camera

If you look past the phenomenal technology that has come to dominate the camera market these days, all cameras actually work much the same as the antique cameras you might see in a museum. At its heart, a camera contains some method of recording the light hitting a surface. Many cameras still use film for this function, but a growing number use some sort of electronic device to record the image. A charged couple device (CCD) is by far the most common method of recording digital images, though more advanced cameras generally use a CMOS or other chip for the same function. I will use CCD throughout this article, even though the principles apply equally to other technologies for image capturing.

Given that the sole purpose of the camera is to record light on a surface, the science of photography centers around getting an appropriate amount of light to that surface. There are basically two ways of controlling the amount of light that hits the CCD. The first is to control shutter speed. The shutter is simply a device that blocks light from hitting the CCD until the photographer hits the trigger. Once triggered, the shutter remains open for a period of time, allowing light to hit the CCD. The shutter then closes again. The longer the shutter remains open, the more light will hit the CCD. There are, of course, tradeoffs. The longer the shutter remains open, the longer the scene is recorded. If anything in the scene moves during the time the shutter is open, the movement will be recorded as a blur. The same applies if the camera moves relative to the scene. A photographer with a very steady hand will be able to shoot images at slower shutter speeds than a photographer with shaky hands, but eventually everyone must rely on a tripod or some similar method of bracing the camera against movement. Of course even the steadiest of cameras does no good if the scorpion moves while the shutter is open.

The other way to control light is setting the aperture. The aperture changes the size of the hole through which the light enters the camera. The larger the hole, the more light is let in. As with the shutter, there is a trade-off with aperture -- the wider the aperture, the narrower the depth of field. Depth of field refers to the amount of a picture that is in focus. When taking pictures of people, photographers will often narrow the depth of field intentionally so that the person is in focus in the foreground, but the background becomes out of focus and blurry. While this can work well when taking pictures of big things, when taking pictures of small things like scorpions it is often difficult to get the entire scorpion in focus unless the aperture is made narrower to maximize the depth of field.


Figure 1 - This image was taken with too wide an aperture. You can see that not all of the scorpion is in focus.

With all of this in mind, photography becomes a balancing act between shutter speed and aperture. For casual photography, this is all rather bothersome. That is why most of the cameras sold have automatic modes that take care of all of the balancing for you. This is fantastic for taking pictures of your brother’s birthday party or your new car. When it comes to taking pictures of fluorescing scorpions, however, you need to take over and control your own settings.

Macro Photography

To take photographs of scorpions under blacklight, you must first be proficient at taking pictures of scorpions under regular light. The biggest challenge to scorpion photography is the size of the scorpion – even the largest of them is, in the grand scheme of things, a rather small object. Most point-and-shoot cameras these days have a “macro mode,” usually represented by a flower icon. When this mode is enabled, it allows the camera to focus on objects quite close to the camera. With macro mode, most cameras have minimum focusing distances of between 0 and 5 inches. The minimum focusing distance is the closest the camera can be to the object and still focus. It should be noted that you sometimes don’t want to get the camera too close to a scorpion, lest it sting you. You can usually find the minimum focusing distance for your camera in the manual that came with it or in specifications posted at the manufacturer’s website or other review sites online.

Once macro mode is engaged, your next big concern is your depth of field. As already mentioned, depth of field refers to how much of the image is in focus. If you want the entire scorpion to be in focus, you will have to try to maximize the depth of field. How you go about this will depend largely on your camera. Many cameras will have a manual mode where you can set your shutter speed and aperture manually to your desired settings. Usually these cameras will also have an aperture priority setting where you can set the aperture yourself and it will automatically select the shutter speed needed for correct exposure. Regardless of the mode, your goal is to make the aperture quite small, allowing for a large depth of field. Aperture is measured in f stops, with the larger number being the smaller aperture. So you want to set your f stop to a large number. Usually f/9 or higher will do – though you may want to play with settings to see what works for your camera and setup.

With your f stop set high and your scorpion in focus, the next concern is that enough light hit the CCD. With the f stop set high, the amount of light entering the camera is relatively small. In normal macro photography, you can often increase the amount of light on a subject by using supplemental lights, your camera flash or by shooting on a bright sunny day. This allows you to shoot at a narrow aperture while maintaining a reasonably quick shutter speed. If your camera does not allow you to manually adjust the aperture, this may be the only option for you. Adding more light will allow the camera to automatically set a smaller aperture.

The alternative is to slow the shutter speed down to a point where you can record the image with lower lighting levels. With such a slow shutter speed, a tripod or some other stabilizing mechanism may be needed. One good method of working at ground level is to use a beanbag or rifle bench bag to stabilize the camera. At very slow shutter speeds, even the pressing of the trigger button on a stabilized camera can cause unacceptable levels of camera shake. To bypass this, some cameras have a remote shutter that can be plugged into the camera or trigger it by infrared signals so that the camera need not be touched. If your camera does not have this option, it is also possible to use a self timer option to allow you to press the trigger button and then remove your hands from the camera before the picture is taken. Most self timers are around 10 seconds to allow you and your friends to assemble in front of the camera for a snapshot. Some cameras, however, have a short 1 or 2-second delay to allow for just the type of delayed trigger you need for shots at very slow shutter speeds.


Figure 2 - Whether your hand is shaking or the scorpion moves, a slow shutter speed can result in a blurred image.

While such slow shutter speeds do allow you to take shots you might otherwise not be able to, it must be noted that should the scorpion move the shot will be ruined. Fortunately, should you manage to convince your scorpion to hold a pose, they are incredibly stable – much more so than the average photographer’s hand. Thus, slow shutter speed shots can be an effective way of capturing good images. This is important, since blacklight shots require that you do not use a flash or any other bright supplemental lighting.

Blacklight Photographs

Blacklight shots of scorpions follow all the basic rules of macro photography, but with some added twists. The first twist is that, as already mentioned, you do not have the option of supplemental lighting. You do, however, have the option of what sort of blacklight you use and where it is placed. For the purposes of blacklight photography, you want a light source that produces the least visible light while still producing enough UV light to make the scorpion fluoresce. For example, an LED light producing 395-400nm light will make the scorpion glow, but also produces a lot of purple light. An LED light producing 390-395nm light will make the scorpion glow just as well but will produce less visible light. Regardless of the light source, you want to place the light close enough to the scorpion to allow it to fluoresce but far enough away that it does not illuminate the surrounding environment too much. If placed correctly, there will be a good contrast between the glowing scorpion and the dark background. The use of a clean, dark, light-absorbing fabric like black velveteen can greatly enhance the effect. The selection of too wide an aperture or too slow a shutter speed can destroy the effect by capturing more of the visible light.


Figure 3 - An overexposed image may show the background and wash out the details of the scorpion.

Next, you want to set your aperture to maximize your depth of field, just as with macro photography. When it comes to your shutter, however, the lack of strong light will require a slow shutter speed. This, in turn, will require some sort of camera stabilization. Most often, then, a blacklight photograph will involve a well stabilized camera with a narrow aperture and a slow shutter speed.

The final twist in blacklight photography is issue of focus. Some cameras will have no issues focusing on the fluorescing scorpion as they would on any normally illuminated subject. Others, for whatever reason, do not seem to be capable of recognizing the scorpion as a focal target. At this point it pays to know your camera. You may be able to manually set the focal distance or “trick” the camera into focusing by using a white light to illuminate the scorpion for focusing and then “locking” the focal distance (most often by holding the trigger button down half-way) before turning out the white light and taking the picture.

Finally, when all is said and done, you ought to have yourself a decent picture of a scorpion under UV light. The trick now is to fine tune all of the settings to get just the right effect.


Figure 4 - The final product, straight out of the camera.

Photoshop

Often a good photograph can be turned into an absolutely great photograph by some post-shooting modifications. While Photoshop is probably the most common software for this type of photo editing, there is other software out there that can also help bring out the best of the photograph.

A complete tutorial on the use of Photoshop is beyond the scope of this paper. Most often, though, the picture will be edited to remove any specs of dust or other visible background that may spoil the contrast between the scorpion and its background. The overall contrast and saturation may also be increased to add to the stunning effect a fluorescing scorpion can have. A word of warning, however, that overdoing post-processing can destroy the natural look of the shot and may misrepresent the phenomenon that is being documented.


Figure 5 - The final product with some touch-up work. The dust has been removed and the contrast and saturation raised.

The Last Word

As with most anything, knowing the theory helps but practice is a necessity. The more shots taken the better the photographer will get. While I hope this article was informative, it is not the last word in blacklight photography and there is still much to be learned from experience. As always, if there are any questions please contact me.