Photography How To: Streaked Headlights

A new regular blog feature which will post an image, either new or from the archive, and explain the photography techniques involved in creating it.

Charing Cross in Glasgow, Scotland at dusk - stock images and prints from Dunmaglas Photography

Charing Cross in Glasgow, Scotland after dusk

I am a huge fan of night photography and the winter months are a perfect time of year to capture night images in the city without having stand around in lonely streets late at night with rather dodgy people hovering around. The dark rush-hour also means there is plenty of motion and, well, general rushing around that can be captured. In many instances night images containing a lot of sky are best captured just after dusk when lights are on, buildings may be lit up, though there is still some light left in the sky –  earlier and the sky may be overexposed – later and the sky may be very dark or black without excessively overexposing the light sources. However overcast skies will often reflect the street lighting especially in larger urban areas and give some light to the sky – even better if there is broken cloud to give some texture and variety.

This image was taken above the motorway underpass at Charing Cross in  Glasgow at the Western fringe of the city centre, facing south towards the Kingston Bridge approach.

In order to capture motion streaks from the traffic headlamps a slow shutter speed is required which means a tripod is essential (obviously an SLR or other camera that allows you to change the shutter speed and aperture settings is essential too that goes without saying). To capture an image of this kind you will need to mount your camera on a tripod and use manual exposure mode. Set to the lowest ISO sensitivity your camera allows (100 in the case of this image), aperture to F/11 or smaller (i.e. higher F-stop number – this image was taken at F/16) . You will want a shutter speed of at least a second to capture traffic motion in this way. In rush hour the traffic may be moving more slowly in a tailback so you will need to set your shutter speed accordingly and adjust your aperture setting to compensate (if shooting in film you could bracket +/- 1.0EV). Since camera metering is less reliable in these kind of lighting situations you may need to take a test shot at the metered exposure value and adjust your exposure if necessary. This image was taken with a shutter speed of 15s which was as metered. If you find that your camera’s metered exposure value produces good results you could try taking this type of image in shutter priority mode (this enables you to set a fixed shutter speed while the camera metering will automatically set the aperture to the correct exposure) to give you faster control of shutter speed and experiment with the extent of motion-blur however I tend to avoid using semi-automatic modes unless the lighting is tricky and/or changinr rapidly or the subject is liable to move on.

To minimise camera shake when pressing the shutter you will want to use a remote trigger however if you don’t have one you can use the self timer setting on your camera to delay the shot for a few seconds – a feature available on most DSLRs.  If your camera allows you to do so then set the shutter release mode to lock the mirror  up before taking the shot. This will eliminate camera shake caused by the motion of the mirror.

Another useful tip is that when shooting where the dominant light source is the street lamps, this will often produce a strong reddish colour cast in photographs – which for artistic reasons you may wish to keep or remove. If you wish to eliminate this kind of colour cast you can do so by adjusting your camera’s white balance. Many people may shoot in either automatic white balance (tut tut!) or use daylight or cloudy white balance settings – both of which can work well shooting at dusk or after dark. If you are shooting in camera RAW (which you are, aren’t you?) then you can make adjustments to the white balance afterwards if need be. Obviously if you are producing black and white images then the white balance will be less of a concern however changes to white balance can still alter the contrast in areas of a photograph so it is still useful to test different settings to see what works best.

This image was rendered with direct sunlight (or daylight) white balance which works well since there is still some ambient light scattered from the sky and balances the (still mild in these conditions) reddish tint that would be produced using the cloudy white balance. When it is darker, there is no light from the sky and the street lights are completely dominant – I find the incandescent or warm-white-fluorescent white balance options work well and retain just a hint of the colour cast from the lights however in this image such settings would have rendered too much of a blue/purplish tint akin to excessive filtering (45 minutes to an hour later and warm-white-fluorescent would have worked well) . The sodium vapour white balance setting will generally tend to remove the colour cast from sodium lights completely, rendering an image more like one taken under daylight lamps and perhaps making it seem slightly artificial. Again it is a matter of experimenting with different settings to determine that which works best for any given image.

To summarise, the camera and settings for this photograph were:

If you don’t understand any of the terminology in this blog post then perhaps your camera’s user manual is gathering too much dust 😉

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