Don’t put your camera away once the sun goes down; there’s plenty of magic to record after dark, whether you’re in a bustling city or an isolated landscape. And you don’t require elaborate equipment if you decide to hand-hold your camera.
A hand-held 1/4-second exposure taken at ISO 3200 with a 16mm focal length using an Olympus OM-D E-M5 camera. The combination of the high sensitivity, slow shutter speed and sensor-shift stabilisation in the camera body allowed stationary elements in the scene to be rendered sharply.
Taking pictures after dark requires the same key controls as you would in daylight ““ but they may be pushed to their technical limits in some situations. Understanding these limits enables you to modify your shooting practices to produce interesting and technically competent photographs.
Shooting in low light levels requires you to make some important decisions about how to balance three vital controls: aperture, shutter speed and ISO. This balance pivots on shutter speed, since it’s the function that determines whether your shot is sharp.
So the first parameter to lock down is shutter speed: how low can you hand-hold the camera without encountering camera shake. This factor should be tested for all camera bodies and lenses you plan to use.
A pose from a traditional Maori haka, captured well after sunset with the Samsung NX1 using a 45mm focal length at f/2.8; 1/80 second at ISO 1600.
An instance where use of a wide lens aperture enables lower sensitivity settings to be used with faster shutter speeds to freeze action. Samsung NX1 with 150mm focal length, 1/160 second at f/2.8; ISO 1600.
The importance of stabilisation
Photographers using modern digital cameras are likely to have access to stabilisation, either built into the camera body as a sensor-shift system or in the lenses they use. Sony and Olympus are the leaders in sensor-shift stabilisation, while most other manufacturers rely on stabilised lenses, in which a ‘floating’ element (or group of elements) is used to re-direct the path of the exposing light in response to camera movement detected by gyro sensors.
Both systems provide similar outcomes. Photographers can expect at least two f-stops of shutter speed advantage at longer focal lengths. This means a shot that would require a shutter speed of at least 1/100 second without stabilisation could be captured at 1/25 second.
Many manufacturers claim their systems can support three or even four f-stops of compensation, although that could depend upon the longest focal length covered. Longer lenses require more correction than lenses with angles of view equivalent to or wider than 24mm in 35mm format, which may not require stabilisation at all.
In most situations, the default stabilisation mode is the one to use. When following a moving subject, switch to the panning mode.
Rainforest environments often have low light levels that can make it difficult to shoot with fast shutter speeds and small aperture settings. This hand-held shot was taken with the Samsung NX1 at ISO 400, using a 20mm focal length with an exposure of 1/15 second at f/7.1.
A hand-held shot taken during twilight with the panorama mode on the Samsung NX1 camera. ISO 400, 68mm focal length, 1/640 second at f/4.
Capturing enough light
Having determined your shutter speed limitations, that next issue to address is how to let enough light into the camera to achieve a satisfactory exposure. This means looking at the lens aperture.
The wider the lens aperture, the more light can enter the camera at a given shutter speed. Consequently, fast lenses are the best choices for low-light shooting. But we can’t all afford a set of fast primes and such a set wouldn’t be particularly portable. So most photographers settle upon zoom lenses ““ which, in the main, aren’t particularly fast.
This is where the third factor, sensitivity, comes into play. Modern digital cameras have overcome many of the issues that faced photographers who recorded on film. Today’s cameras provide much higher sensitivity settings and retain colour accuracy at high ISO settings. But if you use the maximum ISO sensitivity the camera supports, expect a reduction in picture quality due to image noise.
There is a point at which increasing noise makes shots appear very granular, which reduces picture quality. That point varies with different sensor sizes and can be influenced by image processing. Cameras with sensors larger than 12.8 x 9.6mm (‘1-inch type’) should be able to produce ‘usable’ images up to ISO 3200.
An exposure of 1/15 second at f/5.6 with ISO 200 was fast enough for this hand-held shot taken with a Canon EOS 5D Mark II camera and 70mm focal length on the 24-105mm stabilised zoom lens.
Even small-sensor digicams like the Canon PowerShot G10 used for this shot can produce worthwhile results at low ISO settings (ISO 200) when the subject is a brightly-lit cityscape. However, other shooting parameters had to be optimised, requiring the maximum aperture setting of f/2.8 and the camera being held against the window to steady it during the 0.8 second exposure.
Shooting tips
How you deal with exposures will affect the amount of gear you need, your shooting flexibility and the end result you obtain.
The following tips provide some guidelines:
1. Travel light. Depending on where you are, carrying a conspicuous camera at night may not be safe. You’ll be less noticeable with a smaller camera and single lens. Consider using a fast wide-angle zoom or, if you need some ‘working room’, an all-in-one ‘convenience’ zoom lens. Avoid using flash. Be judicious about who and what you photograph. It can help to have a companion to deflect any ‘aggro’ you might encounter and validate your activities. Don’t take unnecessary risks.
A candid shot taken with a Sigma DP3 Merrill camera that has a fixed 50mm lens and no viewfinder. The camera is small enough to be inconspicuous. Use of the raw file format gives images plenty of colour depth. ISO 400, 1/80 second at f/2.8.
2. Know your equipment. Know how to operate your camera in low light and with minimal fuss and ensure you have a good feel for how fast it can focus in different conditions. Be prepared to use manual override if the AF system starts to hunt. Make use of Custom modes to pre-set exposure combinations so you can switch quickly between them.
3. Look for the lights. Seek out places with good lighting and wait for something to happen. Find an interesting light source, look for an engaging angle and watch how the light illuminates the scene and subjects that pass through it. While you’re waiting, decide whether to meter exposures on the light source (which will throw at least some of the rest of the subject into deep shadow) or evaluate the entire scene and hope for an even distribution of dark and light tones.
Festivals like Vivid Sydney provide plenty of opportunities to take interesting pictures after dark. A 1/2 second hand-held exposure at f/4.8 with a 75mm lens on an Olympus OM-D E-M5 camera at ISO 1600.
4. Know what you want. If you’re after action you’ll need a high ISO and fast aperture. If you want to create light trails you’ll need some way to steady the camera (look for a wall or something similar to rest the camera on while taking the shot).
5. Know your location. Check out your shooting location in the daylight before embarking on a night shoot. Find out where the interesting buildings, monuments and parks are and what potential shooting opportunities they offer. Look for places where people are likely to congregate and places where there is water (reflected lights can make great subjects for night photos). Seek out different viewpoints, including from tall buildings and in subways.
6. Check the weather and know what to expect. City lights will look great on a cloudless night. Streets gain additional reflective surfaces after a shower of rain, and snow can add reflective areas that boost ambient lighting and add an all-over glow. But make sure you protect your equipment if it’s going to rain or snow and delay going out in the middle of a thunderstorm. Above all, stay safe ““ and keep your gear safe too.
7. Breathe in and squeeze. Keep your finger on the shutter release and when you have the subject framed perfectly, breathe in and squeeze down on the shutter button. Don’t lift your finger until the shot is captured. This technique will steady both you and your equipment and minimise camera shake with slow shutter speeds.
8. Set the ISO limits. If you know the ISO settings at which your camera’s images become ‘unusable’ it’s easy enough to avoid them by setting the upper limit to the Auto ISO range. Most cameras provide this adjustment. You can then leave the ISO on Auto, overriding it if necessary in the knowledge that you risk visible noise. The Auto setting will always be biased towards low ISO values, giving you the best chances of obtaining relatively noise-free shots.
‘Around the campfire’ shots are fun to have but challenging to take as they generally involve a very wide brightness range and people must sit still during the exposure. Canon EOS 40D with 20mm focal length, ISO 400, 30-second exposure at f/7.1.
Noise reduction
All modern cameras provide some kind of in-camera noise-reduction (NR) processing, which is applied to JPEG files. Most cameras provide separate processing for High ISO and long exposure noise because they require different adjustments.
High ISO NR is handled by the image processor and is based upon calculating whether the actual differences in pixel values constitute noise or genuine photographic detail. They will then average out the former while attempting to preserve the latter.
Since noise levels increase as ISO sensitivity is increased, processing tends to become more aggressive at higher sensitivities. This can produce a noticeable loss of image quality. Details can be smoothed out and colour irregularities may appear in JPEGs recorded with high ISO values.
If you shoot raw files, noise-reduction is part of the file conversion process and you have access to a wider range of adjustments. Different raw file processors provide different adjustments and the best ones allow photographers to fine tune adjustments to suit individual image files.
Noise is inevitable with high sensitivity settings. But effective noise reduction combined with avoidance of the highest ISO settings can produce usable shots. Taken with a 17mm lens at f/3.8 using an Olympus OM-D E-M5 camera at ISO 3200.
‘Usable images’ defined
Deciding what makes an image usable requires you to determine the end use(s) for the picture. Will it be displayed on a monitor screen ““ or printed? And, if printed, how large will the print be? What if you want to use the shot both ways?
For screen viewing, the highest output resolution currently supported is 3840 x 2160 pixels, which complies with the 4K video standard. This is roughly equivalent to an 8.3-megapixel image and most screens support pixel densities of less than 100 (typically 72 ppi).
Tablets and smart-phones may have higher pixel densities but their screen resolutions are less. So for screen-based viewing, images that look good at 3840 x 2160 pixels will fill the bill, regardless of their pixel densities.
Printing images tends to suppress the granularity of image noise because of the way inkjet printers lay down droplets of ink and the resolving power of viewers’ eyes. Modern printers use six or more different inks applied with varying droplet sizes and droplets overlap when hues are blended.
This suppresses the appearance of discrete pixels and results in a more continuous tonal range. Pixel density is also higher, with the most commonly used resolution being 300 pixels/inch. Consequently, an image that looks good on a screen at 3840 x 2160 pixels will withstand close inspection when printed at A4 size or slightly larger. Even larger prints should look good when viewed from further away.
This is an excerpt from Photo Review Issue 62.
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