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 This trend will continue and the techniques and equipment I use today will quickly become outdated.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 August 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". Each time the distance to the light source is doubled, the photographer needs to increase the exposure by 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 effectively 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 light - is great for photographing animals that are stationary. Filament and Xenon arc lamps produce light of good colour quality but are power hungry and not very portable. LED lights are portable, bright and energy efficient but most models produce poor colour quality. LEDS's with high colour rendering index produce high quality colour and are starting to appear in higher-end units. 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 and I used the car headlights for illumination and the camera to determine an exposure of 1/15s at f5.3 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. When sufficient light has been emitted to produce the 'correct' exposure the discharge is terminated. 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 prefer 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 the images also reveals that the maximum 1/4,000s shutter speed on 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. To illustrate the benefit, the images below were taken using a 50mm lens with identical camera/flash settings and image processing
Focusing at night
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 sensors, making the cameras task easier. I believe that 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 auto settings often produce 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 of an object such as a tree trunk, at a known (estimated) distance. With my favourite flash unit set on 1/4 power and camera on ISO 800 I achieve good range and motion stopping ability. Next I calculate a working guide number 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, my working guide number, is 5m x 16 = 80 metres. This working guide number is correct only for the setup for which it was calibrated!
To photograph a subject 10 meters away, I can simply divide the working guide number by the distance ie 80/10 to get f8. If I prefer 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 setting or reduce the camera ISO. Providing, my estimate of the the subject distance was reasonable, the first exposure is usually quite close to the mark.
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 equipment 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 - For stationary birds I use a single central focus point with continuous autofocus. I have the camera set up to focus using the 'backbutton' which makes it easy to reframe the subject without refocusing. For flying birds I use continuous autofocus with multiple focus points selected and use the shutter button to focus and to shoot. 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. Using high ISO is equivalent to using a more powerful flash unit, however the downside is that it also increases 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 is that accurate focus is more critical and some lenses are soft when used wide open.
Shutter - 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 for stationary subjects to record ambient light detail as shown for the Barking owl below, which was taken at 1/15s. The owl remained sharp because it was exposed by flash, whilst the background shows some effects of camera movement.
Flash and low shutter speed can be combined intentionally to give the appearance of motion as shown for the nightjar below. The sharp image of the bird produced by the short duration of the flash is superimposed on the blurry 1/30s exposure resulting from continuous spotlight illumination. By setting the camera flash mode to 'rear-curtain sync', the blurred part of the image can be made to trail the bird to give the impression of speed.
More often than not though, an otherwise good photo of a hard to get subject, such as this grass owl with prey, is ruined!
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 iris colour as is 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 far more natural to me and can be captured using electronic flash by pre-focusing the camera and turning off the focusing light several 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 and head angles. 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 a shallow flash angle.
Sometimes you cannot avoid red-eye as the images above show. When this happens red-eye can often be 'fixed' 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 same images 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 by 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.