Photography

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Published: Sunday, 11 March 2018 07:54

Night photography

 Introduction

I have enjoyed photographing night creatures for nearly 40 years. With the rapid advancement in camera technology and lighting it is now possible to photograph birds flying at night and my techniques and equipment have progressively evolved. The additional equipment required for night photography of wildlife can be as simple as a decent spotlight and an assistant or as complex as you wish. When working from a car or with an assistant, photography in the dark is fairly straightforward. When alone in the dark, adjusting gear and camera/flash settings can be difficult and error prone. I find it helps enormously to pre-configure as many settings as possible and get your gear ready before nightfall. These are my thoughts and techniques as of May 2022.


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 needs to 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 daylight photography, this can be ignored because the distance of the photographer from the sun or the sky does not change the brightness of the subject. When illuminated with artificial light, however, this is not true. The diagram below shows an object located at distance "d" from the light source is four times brighter than an object at twice the distance. Consequently, if the object to light source distance  is doubled, the exposure needs to be increased by the equivalent of two f-stops. If it is halved, the exposure needs to be reduced by the equivalent of two f-stops.

 





Continuous lighting

Light sources such as a spotlights are great for photographing stationary animals. Filament lamps and Xenon arc lamps produce light having excellent colour quality but are heavy and power hungry. LED lights are portable, bright and energy efficient and those having a high colour rendering Index (CRI greatr >80) produce accurate photographic colour rendition.

Exposure is determined using the 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 disadvantage of a continuous source is that it has very low intensity compared to electronic flash and a comparitively long exposure is required, making it impossible to obtain sharp images of moving subjects.

 

Electronic flash

Flash is the ideal portable light source because it emits an intense burst of high colour quality light that can freeze motion. 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 by the clever electronics. The flash-tube contains xenon gas which produces light of excellent colour quality. Most models have auto and manual modes which can be configured to produce  the correct exposure.

To illustrate the advantage of using manual flash over continuous lighting to freeze motion, I photographed an operating ceiling fan, with black lines painted on one blade. Images in the top row below, were taken using a spotlight (continuous source) and camera shutter speeds from 1/500s  to 1/4000s. The bottom row was taken using a fixed shutter speed of 1/200s using flash power settings, from full power to 1/32 power. Comparison of the images reveals that a shutter speed of 1/4,000s is equivalent to a flash power setting of 1/4 and a shutter speed of 1/20,000s is equivalent to  a flash power setting of 1/32. Consequently, night images taken with flash on 1/4 power or less shown virtually no movement or blur.


Flash extender

Combined with a telephoto lens, a fresnel lens placed in front of the flash concentrates the light output.To illustrate this, the images below were taken with and withou a flash extender using a 50mm lens with identical conditions and processing.The flash extender reduced the beam angle to produce a small 'hotspot' with a 3 f-stop gain in brightness.


 

Focusing at night

The 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 effect the ability to focus quickly and accurately at night. Mirrorless cameras unlike DSLR's do not always focus at the maximum lens aperture and I believe they are not currently on par with the best DSLR's for flying birds at night.

LED flashlights can be used to provide sufficient light to focus well on stationary subjects, however flying birds require much higher intensity light to enable fast AF. The human eye is a poor judge of light intensity and what may appear very bright to a photographer may in fact be very dim to the camera AF system.


Exposure determination

With continuous light sources, obtaining the correct exposure is identical to daylight photography.

Using flash, the task is more difficult and is dependent upon equipment and settings. Good results can always be obtained using electronic flash on the correct manual power setting. With some cameras (eg Nikon Z6ii) well exposed images can be obtained with stationary subjects located at distances from 5m to 50m away using the through-the-lens (TTL) flash mode.

At the commencement of a night outing, I 'calibrate' my setup by taking test shots of an object such as a tree trunk at the anticipated subject distance so I know it will work when the critical moment arises.

 

Gear timeline

A summary of the cameras and lenses I have used for wildlife photography at night is shown below.

1974-2004 (35mm film days with manual focus gear) Nikon F2 & Nikon FM2 / Nikkor 300mm f4.5

2004-2010 Nikon D70 / Nikkor 70-300 f4.5-5.6 AF - my first autofocus camera  big improvement on manual focus and film

2010-2012 Nikon D90 / Nikkor 70-300 VR AFS & 80-400 VR - 12 megapixel sensor was a significant improvement over the D70's 6 megapixel sensor

2012-2015 Nikon D7000 / Nikkor 70-300 VR AFS & 80-400 AFS VR - 16 megapixels with improved autofocus enabled me to photograph birds flying at night

2015-2021 Nikon D750 / Nikkor 180mm f2.8 & 80-400 AFS VR - My first full frame digital camera, 24 megapixels, fantastic image quality and better all round

2022 Slow moving wildlife; Nikon Z6ii,  Nikkor 70-300 f4.5-5.6 AFP, 500 f5.6 PF - Possibly even better image quality than the D750 and the electronic viewfinder is a joy because it can be configured to see clearly in almost total darkness. Unfortunately, at night the Z6ii struggles to focus on flying birds. Flying birds; I am considering  using a Nikon D850 and Nikkor 300mm f4 PF lens.

 

Flash brackets

To minimise 'Red-eye', I use a DIY carbon fibre bracket with an intense focus light.


 

Tripod

A tripod is useful for night photography at fixed locations such as perches, roosts or nests. A small lightweight carbon-fibre tripod can support the camera or be used as a stand for an off-camera flash.

 

Off camera flash

Occasionally, I use sync. cables or radio triggers to fire flashes located away from the camera. Previously, I used Nikon's 'CLS' system but found it time consuming to set up and unreliable due to unseen beam path obstructions from foliage and other obstacles in the bush.

 

Camera settings

Settings Banks - Many cameras allow you to save your favourite settings for quick recall. I have pre-configured settings for night photography which I can select by rotating a knob.

Image format - RAW file format has high dynamic range and a high capacity for setting white balance and salvaging shots which would have been over or under exposed had they been taken using jpeg format.


LCD Monitor/viewfinder - At night display screens appears much brighter than during the day and images which appear adequately exposed are often significantly underexposed. To counteract this, I turn the monitor brightness right down and when possible check the image histogram.

 
Shooting Mode - I always set the camera to manual mode for outdoor night photography.


Focus - For stationary birds I use the centre autofocus point with the camera set for 'backbutton continuous autofocus'. Backbutton focus makes it easy to reframe the subject without  refocusing. For flying birds, I use continuous autofocus and multiple focus points. Different camera brands and models have many different autofocus modes so you need to experiment to find which work best for your camera/lens.


ISO - Producing sufficient light for correct exposure or to obtain motion-free images can be difficult. Using higher ISO which is equivalent to using a more powerful flash can help, however the downside is that image noise increases . On my most recent cameras ISO 800 produces 'acceptable' noise which use as my preferred setting.


Aperture - A wide aperture is desirable to isolate the subject from the background and increase the maximum working range of the flash. I usually stop my lens down by at least one f-stop from maximum aperture because accurate focus is easier to achieve and lenses generally perform better when stopped down. Unlike DSLR's mirrorless cameras may not focus at the maximum aperture of the lens!


Shutter speed - The maximum shutter speed should be set no higher than the maximum flash sync speed of the camera which is approximately 1/200s. At night, the surrounds are dark and it is the short duration of the flash which stops motion, not the camera shutter speed.

Very low shutter speed can be useful for stationary subjects to record ambient light as shown for the Barking owl below. The owl remained sharp because it was exposed by the short pulse of light from the flash, whilst the background shows blur from hand-held camera movement during the 1/15s exposure.

 


Illusion of speed - Flash combined with low shutter speed and 'rear-curtain sync.' can be used
to give the illusion of speed. For the Nightjar below, a sharp image of the bird and the illusion of speed was obtained by the short flash duration, combined with a 1/30s exposure where the bird was illuminated by the focus light. This technique is a gamble because a potentially good image, such as the Grass owl with prey below, was ruined by the blur caused by the slow 1/15s shutter speed. In the third image the shutter speed was 1/200s and although the bird is flying away from the camera, the image is sharp.

 

 

 

 

 

Nocturnal Eyes

Pupils - A continuous light source always produces contracted pupils when the bird is looking toward it and there is no way to prevent that. This is especially noticeable for a bird having a light coloured iris such as the young Boobook owl on the left below. Large eyes are a prominent feature of nocturnal birds and if we were able see in the dark we would see that their pupils are always wide open. To me, dilated pupils look natural and can be captured by pre-focusing then turning the focus light off before releasing the shutter, as shown for the image on the right. Electronic viewfinders in mirrorless cameras can see in almost complete darkness and after focus is achieved, the subject can be observed with extremely dim light ( 'moon-glow' intensity) before  the shutter is activated.

 

Red-eye

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, red-eye can be reduced and often avoided. This is illustrated in the diagram and images of a Tasmanian Boobook owl below, which were taken at different distances and head angles. Increasing the lens/flash angle can be achieved via a camera bracket or 'off-camera' flash.


 

Red-eye correction

Sometimes you cannot avoid red-eye as seen in the left and centre images above, however it can often be 'fixed' by 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 but not quite black. You can also 'dodge' the catchlights and eye reflections to enhance their appearance as shown for the same images below. A single light source often produces multiple catchlights due to reflections from the cornea and eye lens.

 

 

Flying birds

Flying birds present the ultimate challenge to me. Sharp images 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 taken 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 one of the camera brackets shown above.

 

Conclusion

My thoughts and ideas are a guide and should not be considered binding, rather as ideas and techniques that have worked for me and which I am constantly modifying. I hope this article can  encourage you to give night photography a go.