Photography

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Published: Sunday, 11 March 2018 07:54

Night photography

I have enjoyed photographing night creatures for nearly 40 years. With the advancement in camera technology and lighting it is now possible to photograph birds flying at night. and my . The additional equipment required for wildlife can be as simple as a decent camera with good focus-light and an assistant. When working with an assistant or working from your car, photography at night is fairly straightforward, however when alone I find it beneficial to pre-configure as many settings as possible before nightfall.

My techniques and equipment described below have evolved over this time and should be considered as a guide which can be improved upon (updated 2023-01-16).

 

ILLUMINATION

Photography in darkness requires either a continuous light source or an electronic flash. There are several important differences between daylight and light sources which a night photographer should understand.

A fundamental of light is that the brightness of an illuminated object, decreases in proportion to the square of the distance from the light source. For photography in natural light, this can be ignored because the relative distance from the light source only changes by an infintesimal amount. When illuminated with artificial light this is not true, as the diagram below illustrates. If the distance is doubled, the exposure needs to be four times longer or two f-stops wider. If the distance is halved, the exposure needs to be reduced by the equivalent of two f-stops.

 

 

Continuous light sources such as spotlights are great for photographing stationary or slow moving animals. Filament lamps and Xenon arc lamps produce light having excellent colour quality but are heavy on battery power. LED lights are portable, bright and energy efficient and those having a high colour rendering Index (CRI greater >80) produce excellent colour rendition.

Exposure is determined with camera metering system by adjusting shutter speed, aperture and ISO. The Tawny Frogmouth below, was illuminated using the car high beam, with camera settings of 1/15s, f5.3 and 9,000 ISO. The main disadvantages of continuous lighting is the relatively low light intensity and the inability to freeze motion.

 

 

Electronic flash is the ideal portable light source because it emits a super intense burst of high colour quality light which can freeze motion, however an additional light is required to enable the camera to autofocus in darkness. Flash units contain complex electronics that produce an electrical discharge inside a transparent tube and when sufficient light has been emitted, the discharge is terminated. Most models have auto and manual modes which can be configured to produce the correct exposure. A typical high power electronic flash (Nikon SB-800); on full power, 1/4 power, 1/8 power, 1/16 power is equivalent to using a shutter speed of approximately 1/250s, /4000s,1/8000s,1/16000s and 1/32000s respectively. This is illustrated in the image below of a ceiling fan photographed at different shutter speeds from 1/500s to 1/4000s and flash power settings from full power to 1/32 power.

 Advanced electronic flash units have several automatic and manual exposure modes. Properly exposed images can be obtained using manual power settings if the subject distance is known. 'TTL mode' (through-the-lens) can produce well exposed images without any knowledge of the subject distance and I use TTL combined with front-curtain sync for most situations. The advantage of TTL is illustrated in the series of full-frame images below, taken with varying subject distances with a flash-exposure-compensation of -1, f-stops.

 

In TTL mode and front curtain sync a pre-flash is fired just before the camera shutter opens, which allows the camera to calculate the amount of power needed for the exposure. Flash exposure compensation is usually required for optimum exposures. At the commencement of an outing, I check my setup by taking a couple of test shots of an object such as a tree trunk, to ensure correct alignment of the flash and determine the amount of flash exposure compensation required. TTL mode and 'front-curtain' sync is illustrated below. The interval between the pre-flash and the main flash is short, of the order of 50 milliseconds and the pre-flash cannot be seen by eye.  With manual power flash there is no pre-flash.


 

 

FOCUSING

Autofocus sensors in DSLR and mirrorless cameras essentially adjust the focus distance to achieve maximum contrast on the image sensor. Illumination intensity, subject contrast, motion, and the particular camera/lens combination effect the ability of a camera to focus quickly and accurately. Mirrorless cameras have different autofocus systems compared to DSLR's and even flagship mirrorless cameras such as the Nikon Z9, are not on par with high-end DSLR's when red-light is used for focusing.

A small flashlight can often provide sufficient light for auto-focus (AF) to work on stationary subjects, however flying birds require far higher brightness. The human eye is a poor judge of brightness and at night what may appear bright to the photographer is often insufficiently intense for the camera to autofocus on flying birds.

 

GEAR

Cameras, lenses and flashes - A summary of the gear I have used for wildlife night photography is shown below.

1974-2004 (my 35mm film days using manual focus lenses) Nikon F2/Nikon FM2 with 'Nikkor 300mm f4.5' and  'Sunpack Auto 455' electronic flash

2004-2010 Nikon D70 (6 Megapixels) with 'Nikkor 70-300 f4.5-5.6' AF lens and 'Nikon SB-800' flash. My first DSLR and autofocus camera was a major improvement on manual focus and film

2010-2012 Nikon D90 (12 Megapixels) with 'Nikkor 70-300 VR', 'Nikkor 80-400 VR' and  'Nikon SB-80'0 flash.

2012-2015 Nikon D7000 (16 megapixels) with 'Nikkor 70-300 VR AFS', 'Nikkor 80-400 AFS VR' and 'Nikon SB-800' flash. Better autofocusing enabled photography of birds flying at night

2015-2021 Nikon D750 (24 megapixels) with 'Nikkor 180mm f2.8', 'Nikkor 80-400 AFS VR' and 'Nikon SB-800' flash. 24 megapixel full frame camera produced fantastic image quality and better results all round

2022 Nikon Z6ii (24 megapixels) & Nikon D850 (45 megapixels)  with 'Nikon 300mm f4 PF', 'Nikkor 500mm f5.6 PF' and Nikon SB-800 flash - Better image quality than the D750 and the electronic viewfinder of the Z6ii is a joy because it can be be configured to see clearly in almost total darkness. I use the D850 with 300mm f4 lens for night photography using a 660nm red focus light.

 

Flash extender - consists of a Fresnel lens placed in front of the flash window, which concentrates the light output over a small area. It produces a 'hotspot' with a 3-4 f-stop gain in brightness and is very useful for night photography using a telephoto lens. To demonstate how it works, the images below were taken with a 50mm lens using identical exposure and processing, without and with a flash extender.

 

Focus lights A white focus light can work well but I have found that flying birds often veer away from the light making it difficult to nail the shot. Red light (660nm) is ideal for DSLR cameras because it works well and induces minimal evasive action from the flying bird and green light (550nm) works well for my Z6ii Mirrorless camera when photographing stationary animals. Coloured focus lights are problematic in that a colour cast can result in the final image which is difficult to remove in post-processing. To address the problem I developed the circuit below, which turns the focus light off for approximately 1/20s each time the flash fires. 

 To show the benefit of the circuit the images below were taken using the same ISO, shutter speed and aperture, except the flash was turned off for the image on the right.

 

A selection of red and green focus lights incorporating the circuit is shown.

 

 

Flash brackets can be used to minimise 'Red-eye'. As selection of DIY carbon fibre brackets incorporating focus lamps are shown below


 

Tripods are useful at night at fixed locations such as perches, roosts or nests or during the day for dimly lit locations that require slow shutter speeds or hand holding for extended periods. A portable lightweight tripod can be used to support the camera or as a stand for an off-camera flash.

 

Off-camera flash - Occasionally I use radio triggers to fire flashes located away from the camera. Previously, I used Nikon's 'CLS' system and sync. cables but found them to be unreliable and time-consuming to set up.

 

CAMERA SETTINGS

 Settings Banks - Many cameras allow you to save your favourite settings for quick recall, which is a very useful in the dark.

 Image file format - RAW files have high dynamic range and the capacity for salvaging images which have been over or under exposed and to set the white balance post-exposure.

 LCD Monitor/viewfinder - Display monitors appear much brighter in the dark and images which appear adequately exposed are often significantly underexposed. To counteract this, I turn the monitor brightness down and regularly check the image histogram.

 Shooting Mode - I use either TTL or manual modes.

 Focus - For stationary birds I use the centre autofocus point with the camera set for 'backbutton and continuous autofocus' which makes it easy to recompose the image without having to refocus. For flying birds, continuous AF and multiple focus points works well. Modern DSLR's and Mirrorless cameras have many autofocus modes which need to be explored to find which ones work best.

 ISO - Producing sufficient light for correct exposure or to obtain motion-free images can be difficult. Using a higher ISO is equivalent to using a more powerful flash, however this produces more image noise. On my current cameras ISO 800-1600 produces 'acceptable' results.

 Aperture - A wide aperture is desirable to isolate the subject from the background and to increase the maximum working range of the flash, however, I usually stop the lens down slightly from the maximum aperture to minimise the affects of AF focus errors.

 Shutter speed - The shutter speed should generally be set to the maximum flash sync speed which for most cameras is around 1/200s. In darkness fast shutter speed is irrelevant because it is the short duration of the flash output which exposes the image and freezes motion.

For stationary subjects, a low shutter speed can be useful to record ambient light. The Barking owl below remained sharp because it was exposed by the short pulse of light from the flash, whilst the ambient light is revealed. The foreground branch shows blur from camera movement associated with hand-holding at 1/15s exposure.

 

For flying birds, low shutter speed combined with 'rear-curtain sync.' can be used to produce light trails, giving the illusion of speed, as for the Nightjar below, taken with a 1/30s exposure. Often however, a potentially good image, such as the Grass owl with prey, shown in the second image are ruined by the excessive blur.

 

 

 

NOCTURNAL EYES

Pupils - A continuous white light source always produces contracted pupils when the bird is looking toward it. This is especially noticeable for a bird with pale irises such as the young Boobook owl in  the left side image below. Large eyes are a prominent feature of nocturnal birds and if we could see in the dark we would notice their pupils are always wide open. I consider dilated pupils look more natural  and they can be captured by pre-focusing the camera then turning the focus light off for a few seconds before releasing the shutter (right-side image below). After focus is achieved and before the shutter is released, the subject can be observed through the viewfinder using an extremely dim 'moon-glow' light.

 

Red-eye occurs when the light source is located 'close' to the camera and light reflected from the retina enters the camera lens. By moving the light source away from the camera or moving closer to the subject, the likelihood  of red-eye in your photos can be significantly reduced. This is illustrated in the diagram and images of a Tasmanian Boobook owl below.


 

Red-eye correction -  Sometimes you cannot avoid red-eye as seen in the left and centre images above, however usually it can be 'fixed' with good photo-editing. Pupils almost always have some light and colour, so I prefer to darken them by 'burning' the shadows and mid-tones, then desaturating the colour until they are almost black. You can also 'dodge' the catchlights and eye reflections to enhance their appearance as shown below. In close proximity to an owl at night, a single light source often produces multiple catchlights due to reflections from the cornea and eye lens.

 

 

FLYING BIRDS

Sharp images of a birds flying at night can be obtained by shooting a bird leaving or arriving at a pre-focused destination or by achieving focus in flight. The Tawny frogmouth below, was phoyographed by pre-focusing on the perch it was hunting from and watching with a dim red light until it flew. The Grass owl was focused in flight using a high intensity light source.