There is much to consider when using this technique if frustration and disappointment are to be avoided. However, once mastered there is little doubt that backlighting can be magical and will add both drama and visual impact to your photographs and diversity and interest to your portfolio. There are many subjects to try, my favourites are translucent flowers and foliage or rim lighting of animals and birds. Backlighting will enhance mist, rain and haze adding creativity and atmosphere to landscape images.
The two most challenging aspects of photographing backlit subjects are to adequately eliminate flare and ensure correct exposure. These concerns can be allayed with a little practice, good technique and an understanding of the exposure process.
Flare gives rise to a loss of definition and is probably the most significant area requiring attention, so a measured and methodical approach is needed. It is produced when intense rays of light hit the front element of the lens causing excessive lens refraction, this leads to specula highlights, image softening and loss of definition. Clearly this is to be avoided and there are several ways to overcome this undesirable effect.
Lenses show individual characteristics but in general the more lens elements used in their construction the more vulnerable they will be to flare. With this in mind zoom lenses are more likely to be flare susceptible that prime fixed focal length lenses. Lens coatings also have an impact on flare, modern multi coated lenses consistently outperform earlier models and this alone can significantly reduce most potential flare problems.
In many backlighting situations using a designated lens hood will greatly improve the chances of eliminating flare by keeping stray light from striking the front element of the lens. Indeed, the use of a good quality lens hood can improve saturation in all images.
Having taken the above precautions a final visual inspection of the image through the viewfinder, preferably with the lens stopped down, will show any remaining areas of softness or highlights resulting from flare. This may only require a slight repositioning of the camera to eliminate.
The other challenge in photographing backlit subjects is how best to handle exposure. Overexposure is a common problem in backlighting, as the brightly-lit background will overly influence the camera’s meter; this will turn the subject very dark, indeed almost silhouette like.
Exposure compensation is the answer and it is best to give between one and two stops extra exposure from the ‘normal’ exposure suggested by the camera. Alternatively, take a spot meter reading from the shadow area and expose at the camera’s reading this should require no compensation. As exposure for backlit subjects is tricky it is best to practice various exposure metering patterns and overrides until you are comfortable in approaching various back lighting opportunities that present themselves.