Photography is all about using light to create pictures. But what happens when the ambient lighting is less than ideal? The solution is to modify it in some way. And there are plenty of options available. This buying guide will showcase some of the more popular choices for photo enthusiasts.
|
Flash The simplest way to prevent this is to re-direct the flash light. This normally requires an external flash with an adjustable head that can be swivelled around to ‘bounce’ the light off a light-coloured ceiling or wall. This prevents red eyes and the ‘rabbit in the headlights’ look, producing a softer, more flattering appearance, particularly for portraits.  An accessory flash that clips onto the camera’s hot-shoe allows you to add extra light when it’s needed. Like the Metz 58-AF2 pictured here, most units have adjustable ‘bounce’ heads and support E-TTL metering via compatible cameras. These flashes can also be used in multi-flash wireless set-ups. High-powered portable flash units are also available. Consisting of a hand-held flash head that connects to a battery pack, which is worn on a belt, these systems combine power with versatility, enabling them to be used on location as well as in studio set-ups. When choosing an external flash, consider the following issues: 1. Light output. This is usually expressed as a Guide Number (GN) measured at ISO 100 in metres or feet. Because the brightness of any light source falls off with the square of the distance to the subject, the guide number allows you to calculate the maximum flash-to-subject distance and lens aperture for a correct exposure (GN = distance x f-number). For example, a flash with a GN of 60 (m/ISO100) can correctly expose a subject 10.7 metres from the camera at an aperture of f/5.6. Flash-to-subject distances become longer when the light is bounced or attenuated by a diffuser (see below). A simple rule-of-thumb is to set the aperture one or two stops wider in such situations, although TTL cameras and compatible flash units can measure the distance automatically and apply the necessary correction. Today, GNs are mainly useful for comparing the maximum light output of several flash units or calculating the light output you require when purchasing a flash for a particular application. In practice, most photographers know the guide number and the distance to the subject. To calculate the aperture setting, use the formula: f-number = GN/distance. 2. Adjustability. The more adjustable the ‘head’ of the flash unit, the more options you have for re-directing the light and the more versatile the flash. The heads of most flash units can be tilted through 90 degrees for bouncing light off ceilings. Many can also swivel through more than 180 degrees. Click stops are usually provided at various detent positions. Some flash units also include zoom controls, which moves the flash tube backwards and forwards in the head. This can be used to match the flash coverage to the lens fitted on the camera. You should also expect controls for adjusting the output levels of the flash and choosing between auto and manual modes.  The control panel on a typical enthusiast’s flash gun, in this case the powerful Nissin Di866, indicates the range of adjustments it provides. 3.Camera compatibility. For worry-free exposure setting, make sure the flash can ‘talk’ to your camera’s TTL metering system. Cameras meter for ambient light conditions and flash illumination independently, and provide separate controls for each. Your flash requires the correct electronic contacts to interact with the camera’s AE system. 4. Exposure duration. Flash exposures are normally split-second bursts of light measured in milliseconds so the camera’s shutter speed has little or no effect on flash exposure; only on the amount of ambient light reaching the subject. This should be taken into account to obtain the best balance between flash and ambient lighting. The flash exposure must also occur while the shutter is fully open. Typical ‘synch’ shutter speeds range between 1/60 and 1/125 second, although many cameras also provide high-speed synch modes that support faster shutter speeds.
5. Exposure control. Flash exposures can be controlled by adjusting: 6. Focusing. Some flash units have built-in AF-Assist lights. These are clear red panels on the front which use one or two high-brightness LEDs to project red circles of light striped with dark lines that give the camera a high-contrast pattern to focus on. Typically, they work over a distance of 5-10 metres.
Exposure Metering For studio lighting, it’s best to meter on the subject. Hand-held flash meters can provide an incident reading that will produce very accurate exposures, which take account of all the lights in a studio set-up.  A typical flash meter provides an accurate way to measure flash output and set the camera’s exposure controls accordingly. In contrast to in-camera meters, which measure the light reflected from the subject, incident meters measure the light that falls on the subject. Measurements are taken from as close to the surface of the subject as possible, with the meter facing the camera. A 180 degree translucent plastic diffuser over the metering cell integrates all the light falling on the subject and adjusts the exposure to produce a neutral mid-grey. Because this reading hasn’t been influenced by reflective or absorbent areas in the subject, dark subjects will stay dark, while light ones remain light. (This technique is particularly useful for wedding photography.)
Flash Accessories The most popular modifiers for portable flash units are diffusers and reflectors. Diffusers are normally fitted over the flash head to spread the light, thereby softening the effect of the flash. For portable flashes, they range from translucent panels to fit-over shells made from a white translucent material.  A typical ‘softbox’ diffuser that fits over the head of a portable flash. 
 The illustration above compares the effects of direct on-camera flash with bounced flash and the light from a combined bounce/diffuser head. For studio lighting, the most popular diffusers are umbrellas and softboxes (see illustrations). Reflectors re-direct the light from the flash and can range from cards that attach to the flash head through small, portable discs of white or shiny metallic material to large, flat panels with reflective surfaces. In most cases, the flash is pointed at the reflector, which ‘bounces’ the light onto the subject. The result is a gentler, more widely and evenly distributed illumination of the subject.  Portable reflectors can be used with on-camera flash units, portable flashes and studio lighting, as well as available lighting, to redirect the light onto the parts of the subject where it’s needed. These Lastolite Tri-grip units can be hand-held to allow their positions to be easily adjusted. One nice thing about reflectors is that they can also be used with available lighting to change the quality and amount of light on the subject. They are particularly handy for redirecting light into shadowed areas. Other flash accessories include gobos, barn doors, grids, snoots and coloured gels, each of which is used to modify lights in specific ways. Gobos are usually dark in colour (black or very dark grey) and are used to prevent stray light from flaring into the camera’s lens. Barn doors are a special type of gobo that attaches to the light and provides four-way directional control. Many barn door units have holders for attaching coloured gels.
 David Honl has developed an extensive range of accessories for compact flash guns, including gobos that can be attached to a flash head to simulate the control provided by barn doors.  Coloured gels in Honl Photo’s filter kits enable photographers to add artistic colour effects to flash photographs. Grids and snoots narrow the beam of light, producing a small circle of light on the subject. They are most suitable when dramatic lighting effects are wanted.  Snoots direct the light into a narrow cone, while grids use an array of honeycomb cells to narrow the beam of light.
Ring Lights 
The Metz ring flash shown here is a typical example of a combined flash and diffuser unit that fits around the lens on a DSLR camera.  The Sunblitz Macro Ring Lite RL2400, shown mounted on a DSLR camera, uses an array of LED lamps to provide the omni-directional light source. The light is powered by four AA batteries in the unit mounted on the camera’s hot shoe.
Studio Lighting  Studio flash kits usually consist of two or three flash heads with reflectors and light stands. An entry-level kit can be purchased for less than $400 while a more sophisticated kit, like the Glanz Mini Pioneer 250Di kit shown here, is available for just under $800. Portraiture and product photography are the main applications for studio lighting, the latter also covering photography of scale models and tabletop set-ups. If these aspects of photography interest you, it can be worthwhile investing in a studio lighting kit.
Studio lighting can be split into two categories: flash and continuous. Flash equipment is popular for the following reasons: 3. Flash bursts are very brief, so the pupils in subjects’ eyes remain at a normal size. 4. Flash output is consistent, making it easy to calculate exposures. Studio flash heads also come with ‘modelling lamps’. These continuous light sources are fitted just above the flash tube and emit a beam of light that shows the angle of coverage of the flash and approximates the intensity of the flash burst. This makes studio flash lighting easy to set up because you can see beforehand the effects produced by each light. In most cases, Monobloc (or Compact Flash Heads) will suit most photographers. These units have their electronics built into the head, along with a holder for the modelling lamp, the flash tube, simple circuitry and a cooling fan.  This Elinchrom BXRi 500 Monobloc flash head it typical of the compact professional flash heads used for studio lighting. Power Packs consist of a floor-standing unit containing all the electronics. Separate heads are plugged into this unit and controlled by it. The parts that generate the most heat are housed in the head away from the electronics in the pack, which is also fan cooled. They are generally used when a huge amount of power is required and when the units are going to be used at high speed over long periods (eg, for fashion photography). The main advantage of continuous studio lighting is that you can see exactly where the light is going and where the shadows and highlights occur. Continuous lighting is also less expensive that studio flash lights because it is technologically simpler. The original continuous studio lighting kits were based on incandescent lamps and these systems are still available, although most use halogen lamps, which are more efficient. However, we’ve seen a shift in favour of compact fluorescent lights in recent years, and more recently towards LED lights with a colour temperature between 2700 and 2800K. These lights are particularly suitable for close-up work and ideal for product and tabletop photography. The new types of lighting overcome the two main problems associated with tungsten lights: heat generation and a strong red/orange colour balance. Both fluorescent lamps and LED lights are comparatively cool and their colour balance is much closer to normal daylight. However, users should still carry out white balance measurement before shooting to avoid any possibility of colour casts. A basic kit containing two Monobloc flash heads with a synch cord, light stands, umbrella reflectors and a carrying bag can be purchased for less than $1000. Expect to pay more for kits with more powerful flash heads plus additional lights and light modifying accessories.  More sophisticated studio kits, like the Bowens Gemini GM200 shown here, combine robust construction with high performance, adjustability, and the ability to be used in studio environments or on location.  A basic studio set-up for portraiture, showing a monobloc head with an umbrella diffuser that is positioned to one side of the subject.
Studio Accessories Various types of grids can be fitted to larger reflectors to further modify the light, making it softer or intensifying highlights. Grids come with varying angles to suit different applications.  
  Some of the light modifiers available for studio lighting.
Equipment Rental  Full lighting kits can be rented from most professional imaging specialist outlets.
Renting is a great way to try out equipment you think you may want to buy. It’s also the most economical strategy for photographers who only require studio equipment once in a while. C.R. Kennedy and Company (www.crkennedy.com.au): Bowens studio lighting equipment, Metz flash guns and meters. Film & Video Extras (www.fvextras.com): Nissin flash guns, Luxmen LED continuous lighting systems, Glanz studio flash kits and accessories, FalconEyes accessories for flash guns, Portaflash meters, Sunblitz ring lights, Pixel wireless flash triggers.
Garage Brands (www.garagebrands.com.au): Gary Fong portable flash accessories and kits. Verbatim (www.verbatim.com.au): LED light bulbs. Note: All major camera manufacturers offer branded flash units designed to suit the cameras in their ranges that will accept them. This is an article from Photo Review Magazine March-May 2011 Issue 47.
Subscribe to Photo Review:
|
