Taking photos of the Split Point Lighthouse in Victoria’s Airey’s Inlet, I was enjoying playing with the different light-sources, particularly the interplay between the lighthouse beacon and the extravagance of the Milky Way behind it. While the lighthouse tower was being lit by the headlights of cars travelling on the Great Ocean Road some distance away, the relatively short exposure times (30 seconds and less) coupled with the darkness and the very low ambient light (no major towns or moonlight) meant that the lighthouse tower was relatively underexposed.
The use of flash in photography to light up a dark scene is well understood by even the most amateur of photographers, and ranges from the auto-flash on a point-and-shoot, to complicated arrays of flashguns, strobes, slave units and so forth that a studio photographer might set up for a modelling shoot (and of which I have very little knowledge).
It involves the artificial projection of a brief burst of high intensity light which, if balanced correctly with the aperture and distance from the subject (light beams following an inverse-square law dictating their intensity), can give the main subject an appropriate level of light to be correctly exposed on the sensor/film/plate (note as explained elsewhere that shutter-speed rarely has a lot to do with controlling the intensity of flash on a scene, as the flash of light is usually far shorter than the length of the shutter’s opening; exceptions exist in the realms of strobe lighting and high-speed film).
In long-exposure photography it’s possible to use flash to light up a part of your image. Balancing the intensity of light, aperture and distance, a nearby static object can be illuminated sufficiently to imprint on the sensor, while the longer shutter-speed will continue to soak in the background to the desired level of exposure. In effect you are freezing the subject with the flash and then allowing it to disappear- something which can allow you to create some interesting effects.
However a flash is a single and momentary burst, and to get that exposure to the right level can be a tricky prospect. Another option in long-exposure photography is to supply a less intense source of light over a longer period until the desired level of exposure is achieved.
In the case here, I used my LED headlamp to cast a beam up and down the lighthouse tower (moving it up and down over several seconds) during part of the 30-odd second exposure. This allowed the lighthouse to be illuminated for the sensor to a desired level, while still allowing the sensor to pick up the crisp starlight behind as well. You can see the slightly patchy light and shadow patterns which are where my headlamp’s beam went over itself a few too many times while missing out other areas.
The technique is known as light-painting, and has far more applications than I have chosen to use here. It should be noted it is far more art than science, and generally involves some trial-and-error, and experimentation. Among other advantages of light-painting over flash are: partial illumination (i.e. chosing which part of the frame to light up if you want others to fade into darkness- whereas a single-source flash will generally light up an entire scene in an even manner relative to the distance from the light source); using different colours; and playing with movement (you’ve all seen photos of car headlights at night-time and how they streak; same principle).
At the end of the day, it’s a bit of fun and an opportunity to experiment with light and the image to see what effect can be created. Here, light-painting enabled me to ‘leave out’ the ground so that the lighthouse hangs by itself against the dark backdrop, and the unsightly parking lot at its base remains black- where a flash would have lit up the asphalt. Additionally, a point flash would have cast more light onto the base of the lighthouse (closer) than the top, whereas with a light source controlled by me, I was able to focus it a little more on the higher reaches of the lighthouse so that they didn’t fade into obscurity. While I haven’t got a perfectly balanced effect, it’s certainly less pronounced than it would have been with a flashgun.
Next time I’m keen to play with colour and with more creative uses like selective painting and motion. In the meantime, I had a lot of fun with this shoot and I hope the output has given you something to look at.