Posts Tagged ‘drop’by tnowack on June 7, 2012 in Blog with No Comments
This entry is the fifth in a series of five detailing the techniques, equipment, and setups to photograph insects on a macro level. The first entry in this series is located here.
The positioning of every piece of equipment is just as important as the settings used. To properly illuminate the drops of water, the 580EX is placed behind the stream of water and facing the camera. If a black background is desired, the flash is lifted out of view of the camera and a black photo board is placed behind the subject. In a dark room, the black board hides any objects inadvertently in the shot and creates an illusion of dark infinity behind the subject. While only one flash is required for drop photography, the second flash is almost essential to capture the drops and insect subject. The two heads of the MT-24EX are placed in different locations. For my setup, the A Head is aimed from the left and vertically in plane with the mosquito while the B Head is positioned adjacent to the lens on the right and aimed directly at the mosquito. The B Head is approximately 3 times closer to the subject than the A Head. Because I am forced to use the lowest power of flash to capture motion, I use the distance the flash is from the subject to change the amount of saturation of light, with closer flashes providing greater illumination. The MT-24EX and 580EX are also aimed in such a way that they do not illuminate the pins tethering the mosquito. This is partly accomplished with the use of cardboard light deflectors that direct the light away from the pins. This setup was determined by trial and error, and adjustments were made until I finally got a rig that produced the best photo.
For a backlit photo, the 580EX is moved downward and angled directly at the camera. The A Head of the MT-24EX moves to behind the stream aiming at the drops and the B Head remains in place to illuminate the subject. This setup results in a clean National Geographic insert style image, but does result in extremely soft edges around the subject. With mosquitoes, the details of the fine hairs and legs are lost due to the backlight, which I felt was unacceptable. Therefore, I modified the rig to simulate a backlit photo by bouncing a flash off a white photo board behind the subject. The background of the image is the board not the light, and the bounced flash
fills any shadows caused by the subject illuminating flash. With some minor contrast correction in post processing, the result is a cleaner, crisper backlit style photo. To see an example of a backlit style shot, see the butterfly photo in the Macro Insect gallery while the bounced style can be seen here. To hold each flash, I use two Manfrotto 196AB-3 Articulated Arms; two Manfrotto 237HD Heavy-Duty Flex Arms hold the MT-24EX heads. The arms are attached to the work bench with Manfrotto Super Clamps. The articulated and flex arms allow for easy positioning of the flash heads and are strong enough to hold the weight of each flash at awkward angles. Holding the camera is a Manfrotto 055XPROB Pro Tripod with a Manfrotto 229 3D Super-Pro Head.
This entry is the fourth in a series of five detailing the techniques, equipment, and setups to photograph insects on a macro level. The first entry in this series is located here.
With the drops correctly captured, my next challenge was with my mosquito subjects. Mosquitoes fly in seemingly random patterns and exhibit varying flight scenarios and characteristics. As a result, capturing a mosquito flying through the cameras pre-determined plane of focus is a very difficult task to accomplish. To eliminate some flight variability, I designed an acrylic box that would house a mosquito. Inside the box was a wall with a square hole, whose dimensions matched the cameras sensor size, removed from the center. Above this hole was the valve sensor, which would drop the water onto the mosquito as it traversed the gap from one side of the box to the other. The idea here is that the camera would be pre-focused at the wall opening. Then, when the mosquito moved through the opening it would be in view and in focus. At that instant, I would actuate the Camera Axe, hit the mosquito with the drop, capture the image and Bob’s your uncle. However, nothing is that easy when working with live subjects. When confined in a sealed box, mosquitoes land and refuse to move. Additionally, present with insects with a hole in a wall, they traverse the gap only randomly (i.e they don’t actively move towards the hole). Meaning, if you somehow stirred the mosquitoes to move in the box, they only moved to the hole in the wall after long periods of time. This is how the backlit images of mosquitoes was captured, but it was a very time consuming process. Coupled with the need for user activation of the camera rig, a new plan was needed.
The solution was to tether the mosquitoes in place and then hide the fact that they are restrained. To accomplish this, the mosquito’s rear legs are each attached via superglue to a pin. The two pins are attached to a plate and suspended in front of the camera. The pins are hidden from view by aiming the illuminating flashes away from the pins; in the dark room they are completely invisible. After reviewing high-speed footage of tethered and non-tethered mosquitoes, the attachment of pins does not alter how the mosquito flies or behaves, but only restrains the mosquito to a single location. To attach the insects, a syphon is used to extract one mosquito from a canister containing dozens.
The isolated bug is placed in a small dish, covered with a lid to keep it from flying away, and moved to the freezer for about one minute. This slows the mosquito’s movements temporarily allowing for the pins to be attached and super glue to dry. When the mosquito warms back up, it resumes normal behavior completely unharmed. The pinned mosquito is placed in front of the camera and the Camera Axe is activated to capture the shot. It should be noted that things never went as smoothly as described here: bugs fly away during transfer, glue fails, drops miss, and worst of all, collisions disable and maim some mosquitoes. In all, what seems from this description as a relatively simple shot with the gear and technique described here became a week-long photographic nightmare. The process of tethering a mosquito takes around 20 minutes and often resulted in only one photo before in mosquito flew away or was too damaged to continue. So, you repeat the tethering process over and over and over; patience and fortitude are musts.
This entry is the third in a series of five detailing the techniques, equipment, and setups to photograph insects on a macro level. The first entry in this series is located here.
To capture the falling drops, the normal rules of photography are seemingly reversed. Instead of instinctively shooting with a shutter speed as fast as possible, I set the camera to a longer exposure, around ¼ of a second, and shoot in a completely dark room. While the 1D has a 1/8000 second maximum shutter speed, the need to shoot with an extremely closed aperture for increased depth of field results in needing a very strong lighting, which can disturb live subjects, and high ISO, which adds noise. Instead, a sudden burst of a flash captures the drop in place. This works simply because in a dark room the quick flash illuminates the subject for only a short period; before and after the flash fires, the environment is completely dark. In essence, we are creating a faster shutter: completely dark (shutter closed) -> flash fires (shutter open) -> completely dark (shutter closed).
Additionally, the flash power must be set to as low as possible (on the 580EX II this is 1/128 and on the MT-24EX is 1/64). Again, this goes against instinct, especially shooting in the dark, as one would think flash power would positively correlate with subject velocity. However, a flash’s power (read: light output level) is created by lengthening the amount of time the flash fires. A flash on full power (1/1) is firing for 1/1000 of a second, while at 1/128 power is only firing for 1/35000 of a second. When shooting in the dark on a virtual bulb exposure, the fast flash acts like the opening and closing of the shutter – except that it occurs almost 4 times more quickly. Too much power, and the subject is illuminated too long, and motion blur results – just like using a slower shutter speed in the daylight. I use the 580EX to capture the drops and subjects’ movements; the MT-24EX is used to illuminate the subject, here a mosquito. I leave my ISO around 400, which provides me with the best black saturation for the background and subject illumination in the foreground, but this value can be adjusted for different scenarios without much disturbance.
This entry is the second in a series of five detailing the techniques, equipment, and setups to photograph insects on a macro level. The first entry in this series is located here.
My main goal in macro photography is to capture the most detail through magnification while not compromising the focus of the subject. This is done through proper camera and lens choices and pushing the equipment to its maximum abilities. For all my research shots, I use a Canon EOS-1D Mark IV. Its full frame senor is ideal for almost all scenarios and has incredible low light sensitivity (yes, full frame sensors do decrease the available depth of field compared to standard frame sensors, but I’ve found this effect is seemingly negligible). Mounted to the camera, I use, primarily, the Canon MP-E 65mm 1-5x Macro Lens. The 65mm offers an unmatched level of magnification; set at 5x magnification or a 5:1 magnification ratio, 1mm of subject is captured as 5mm on the sensor plate. For an example of full 5x magnification see Macro Insects gallery. However, the 65mm can only be stopped down to f/16 resulting in a maximum depth of field around 2.24mm. This small depth of field means that in order to have my subject mosquitoes fully in focus they must fly perpendicular to the camera. Even then, some of the wing and leg structure details are lost; this is a trade-off using the MP-E 65mm for its magnification powers. Coupled with this extreme small depth of field, the 65mm lacks an image stabilization system and autofocus drive making a tripod absolutely essential. When I need slightly more depth of field, I switch to the Canon EF 100mm f/2.8 USM Macro Lens, which can be stopped down to f/32 and gives 4mm of working depth. This amount will allow for the body of the mosquito to be fully in focus. The 100mm can autofocus, which is helpful (and extremely fast and accurate), but does lack the magnification ratios the 65mm provides. The black-background mosquito pictures are taken with the 65mm, the white-background with the 100mm.
For lighting, I use a combination of Canon speedlites: the 580EX II, the MT-24EX, and occasionally the MT-14EX ring flash. I find my subjects react to the ring flash and colors are often distorted, so I rarely use it anymore. The settings and placements of the lights I will discuss later.
Lastly, I recently added a few pieces of specialty equipment to my arsenal: the Camera Axe and Valve sensor. I can honestly say this equipment is absolutely required to get this shot. The Camera Axe is a device that can drive the camera and flashes with varying delays and outputs as determined by the input sensors.
Here, the camera axe actuates a solenoid valve which opens to release a stream of water, then closes. The length of time the valve is open is determined by the user and determines the size of the drops the result. The camera axe the drives the camera and flashes to fire after a user-entered length of delay that matches the height and speed of the falling drop.
As part of my research photography, I was recently asked to attempt to photograph a collision between a drop of water and a flying mosquito and a mosquito flying in a field of drops for a research article determining how these insects can fly in the rain. While seemingly straightforward, this quickly became one of the most difficult shots I have ever attempted. In a fraction of a second, I needed to capture – in focus – the flight path of a mosquito timed perfectly with a falling drop of water, all with enough magnification to provide enough detail and aesthetic beauty to wow readers. After many days of trying, I think I finally got the results I was striving for, which is shown here. I will publish a full gallery as soon as the copyright licenses from the journal have expired, so for now please excuse the watermarks covering the images. My main goal now is to provide detail on how I managed to capture this image, as there is a very steep learning curve in macro-photography and very little documentation on procedures, equipment, and setup. Many people have asked me how I managed to get these unique shots, so I decided over the next few posts I would chronicle the equipment, setups, and techniques I use to accomplish my macro shots.
I took these images as cover art submission for a prestigious research journal, in hopes that I could generate interest in the work we are doing here at the labs at Georgia Tech. My other macro photography works can be viewed in the Gallery section under Research, and include shots of fire ant raft formations submitted for the research journal, Proceedings of the the National Academy of Science. These images were later published on major news outlets like Fox News, MSNBC, Wired, and National Geographic. Please do not repost, reproduce, or copy this material for personal use without my consent, as this material is yet to publish.
Please do not repost, reproduce, or copy this material for personal use without my consent, as this material is yet to publish. However, if I fail to answer any questions you may have, please leave a comment or send me and email at email@example.com.