Photographing Nocturnal Animals
I have enjoyed photographing night creatures for over 30 years and my ideas and equipment have continually evolved. With the rapid advancement in camera technology and the advent of LED illumination it is now possible to photograph birds flying at night. This trend will continue and the techniques and equipment I use today will quickly become outdated. For those interested in this type of photography the additional equipment that is needed can be as simple as a decent spotlight and an assistant or as complex as you wish. These are my thoughts and techniques as of February 2018, which I hope will provide insight and tempt you to venture out at night and enjoy your photography in a different light.
Photography in darkness requires the use of artificial light in the form of either a continuous light source or electronic flash. There are several important differences between daylight and light sources which the experienced night photographer understands and is familiar with.
A fundamental characteristic of light is that the intensity (brightness) of light reaching an object, decreases in proportion to the square of the distance from the light source. The diagram below shows that if an object is located at "d" it would be four times brighter than if it was located at "2d" which is twice as far from the light. Each time the distance from the light source is doubled, to obtain the same exposure the photographer must increase the exposure by the the equivalent of two f-stops. Likewise, if the distance is halved the exposure needs to be reduced by the equivalent of two f-stops.
For outdoor photography during daylight, the sun is so far away from Earth that the brightness of an object does not vary with distance and this characteristic of light can be conveniently ignored. However, a photographer on Mars which is 1.5 times further away from the sun, would need to increase the exposure by the equivalent of one f-stop.
Continuous lights - are great for photographing animals that are stationary. Filament and Xenon arc lamps produce light of good colour quality but they are not very portable. LED lights are portable and bright but they produce poor colour because most models use LED's with low colour rendering index. LEDS's with high colour rendering index are available and will soon appear in higher quality LED lights. With continuous light, exposure is determined using the camera metering system by adjusting shutter speed, aperture or ISO. The Tawny Frogmouth below was sitting on a fence post by the roadside and I used the car headlights for illumination and the camera to determine an exposure of 1/15s at f 5.3 and 9,000 ISO.
Electronic flash - the ideal portable light source. Flash units contain complex electronics that produce an electrical discharge inside a transparent tube and terminate the discharge when sufficient light has been emitted. The flash-tube is filled with xenon gas which produces intense light having a colour comparable with midday sunlight. Most models have an auto mode, however I recommend using one that also has manual power settings which control the light output in f-stop increments.
The composite image below shows a series of photos of an operating ceiling fan. One blade was painted on the edge with white paint and black lines. Images in the top row were taken using continuous light and show the effect of camera shutter speed in stopping motion. The bottom row, taken using an electronic flash on different power settings at a camera shutter speed of 1/200s, illustrates the superior motion stopping ability of electronic flash. Comparison of these images also reveals that the maximum 1/4,000s shutter speed of my camera is equivalent to a power setting of 1/4 and the motion stopping ability of the 1/32 power setting is equivalent to a staggering shutter speed of around 1/20,000s.
Flash extender - a Fresnel lens placed in front of the flash is a useful aid to a telephoto lens at night. It concentrates the light into a narrow beam, typically providing a 2-3 f-stop increase in light intensity at the expense of reduced illumination angle. The images below illustrate the benefit of a flash extender and were taken using a 50mm lens with identical camera/flash settings and image processing.
The various types of focus sensors used in DSLR cameras essentially measure subject contrast. The camera continually adjusts the lens focus until maximum contrast is obtained at the focus point indicated in the viewfinder. Illumination, subject contrast and movement, independently affect the cameras ability to focus accurately and quickly. At night, additional illumination is required for the system to work efficiently.
LED flashlights and spotlights provide sufficient light output to focus on stationary subjects, however flying birds require very intense illumination to enable the camera to rapidly achieve focus. A fast telephoto lens is also helpful as it increases the amount of light received by the autofocus sensor. I am of the belief that deep red light is ideal for watching and focusing on stationary animals because nocturnal eyes have very poor sensitivity to red light, which therefore causes minimal disturbance.
Obtaining correct exposure with a continuous light source is achieved using the camera metering system. Auto-flash (TTL) relies on the camera in conjunction with the flash unit to determine when to terminate the light output. Auto-flash, like a camera in full auto mode, does not compensate for variation in subject contrast or background brightness and outside at night often produces disappointing results. For this reason I prefer using flash on manual power settings.
Prior to a night outing, I "calibrate" my camera/flash set-up by taking test shots at night of an object of average shade and contrast such as a tree trunk, at a known distance. My flash on the 1/4 power setting and camera on ISO 800 gives good shooting range and motion stopping ability. I then calculate a working guide number for those settings which I record on a piece of white tape on my flash extender for quick reference. For example, if the best test shot of a tree trunk 5m away was f16, the working guide number, is obtained by multiplying 5 x 16 to get 80 metres. This working guide number is correct only for the setup which it was calibrated!
To photograph a bird 10 meters away, I can simply divide the working guide number by the distance ie 80/10 to get f8. If I decided to use f5.6 instead of f8, I would need to either reduce the light output from the flash by one f-stop, by reducing either the power or the ISO. Providing I estimated the subject distance correctly, the first exposure is usually close to the mark.
Many modern flash units such as the Nikon SB-800 have an illuminated LCD display where you can set the f-stop, ISO, zoom head position and then simply adjust the power setting to match the subject distance. This is a very simple and fast way to get a near-correct exposure first time.
Gear and handling
When working from a car or with an assistant, photographing an animal in the dark is pretty straightforward. When you are alone and in darkness, simple tasks such as changing camera and flash settings and trying to manage lights and other gear is difficult and error prone. If you work alone as I usually do, it is a great help to simplify your setup and pre-configure as many equipment settings as possible to minimise lost opportunities. My general setup is shown below on the left and incorporates an 80-400mm zoom lens, camera bracket, flash with flash extender, and focusing lights. It is simple and robust and makes working in the dark easy. For flying birds I use the set-up on the right which includes camera bracket, very intense focus lights and a fast 180mm f2.8 lens.
Tripod - A tripod is useful for photographing subjects at fixed locations such as roosts or nests. I have used a small lightweight carbon fibre tripod to support my camera or as a stand for an off-camera flash.
Slaves and triggers - Occasionally I use off-camera flash triggered by sync. cables or Pocket Wizzard Plus-X radio triggers which are usually reliable. Previously I have used Nikon's clever inbuilt 'CLS' system which employs line-of-sight infrared signals between flash and camera, however it is time consuming to set up and very unreliable in the bush due beam path obstructions from leaves, branches and unseen objects.
Settings Banks - Many cameras allow you to save your favourite settings for quick recall. My camera has two banks which I have configured for night use, one for flying birds and one for stationary subjects. It saves enormous time and frustration when working in the dark to be able to select your settings simply by rotating a knob.
Image format - RAW file format has a much higher capacity for correcting white balance and for salvaging great shots which would have be spoilt by over or under exposure if they were created as JPG files.
LCD Monitor - At night the monitor screen appears very much brighter than it does during the day and often images which look adequately exposed are considerably underexposed. For night work I turn the monitor brightness right down and for important shots I also check the image histogram to make sure the exposure is OK.
Shooting Mode - My camera is always set to manual mode because I always use flash at night.
Focus - I use the camera back-button to autofocus and the shutter button to shoot. For stationary birds I prefer using a single central focus point with continuous autofocus and for flying birds I use Group area autofocus. I apologise to the non-Nikon users whose settings go by different names. Camera brands and models have a multitude of focus modes and I am not sufficiently knowledgeable to expound on which ones are the best.
ISO - Producing sufficient light to properly expose and obtain a 'motion-free' image at night can be difficult. High ISO has the equivalent effect of using a more powerful flash unit, however the downside is that it also produces more image noise. ISO 800 produces an acceptable level of image noise on my camera (Nikon D750) and I use it as my go-to night setting.
Aperture - Using a wide aperture is desirable to isolate the subject from the background and increase the maximum working range of the flash. The downside of using the aperture wide open is that accurate focus is more critical and some lenses are soft when used wide open.
Shutter speed - When using flash and a DSLR with focal plane shutter, the maximum shutter speed should be set no higher than the maximum flash sync speed, which is around 1/200s for many models. At night, the surrounds are usually dark and it is the short duration of the pulse of light from the flash which stops motion, not the shutter speed. Slow shutter speeds can be useful to record ambient light detail as shown for the Barking owl below which was taken at 1/15s and the bird remained sharp because it was exposed by flash.
Pupils - Unfortunately, a continuous light always produces contracted pupils when the bird is looking toward it and this is especially noticeable with birds having a light coloured iris as apparent for the young Boobook owl below on the left. Large eyes are a prominent feature of nocturnal birds and if we were able see in darkness we would observe that their pupils are always dilated as shown for the adult Boobook on the right. Dilated pupils look natural and can be captured using electronic flash by pre-focusing the camera and turning off the focus light(s) a few seconds before shooting.
Red-eye occurs when the light source is located close to the camera and light is reflected from the retina into the lens. It can be avoided by moving the light away from the camera or moving closer to the subject to increase the 'flash-eye-lens' angle. This is shown in the diagrams below and in the images of a Tasmanian Boobook owl, taken at different distances. If the eyes are at slightly different angles to the camera you can occasionally get red-eye can in one eye only. Increasing the angle can be achieved via a camera bracket or off-camera flash. When red-eye cannot be avoided it can sometimes be removed by skillful photo editing, however, photos with red-eye often lack feather texture due to the flat shadowless illumination associated with the shallow angle. Consequently, I prefer to avoid red-eye rather than having to fix it.
Sometimes you cannot avoid red-eye and when this happens it can often be successfully removed by careful photo-editing. Pupils almost always have some light and colour in them, so I prefer to darken them by 'burning' the shadows and mid-tones, then desaturating the colour until they are almost but not quite black. You can also 'dodge' the catchlights and other eye reflections to enhance their appearance as shown for the Powerful owl image below.
Flying birds present a greater challenge to photograph especially at night. Images can be obtained by shooting a bird leaving or arriving on a pre-focused perch or by focusing on the bird in flight. The Tawny frogmouth below was taken by pre-focusing on the perch it was using and watching it with a dim red light until it flew. The Grass owl was focused in flight using a camera bracket incorporating high intensity lights.
My thoughts and ideas should be viewed as a guide for those interested in night photography. They should not be considered as binding, rather as ideas and techniques that have worked for me. I hope this article can assist you in developing yours skills in photographing nocturnal creatures at night and encourage you to give it a go.