Beyond the Pop-Up Flash
If you haven't shot an image containing a half-moon shadow that looks somewhat like this with your digital SLR, you eventually will. That pop-up flash on your camera has a very sparse range and narrow beam, thusly it provides limited illumination for an area about 10 feet (3 meters) away. Additionally, the light source is too closely positioned to the lens, so not only do you have to deal with the arcing shadow from the lens across the bottom of an image, but occurrences of red-eye will be increased. You will, and perhaps already do, need more light to be shone on your subjects, and you may want to control not just the power but modify the direction and diffusion as well. Selecting a shoe-mount flash that is dedicated to your camera system and best fits your professional or creative needs should be an easy choice once the options and individual characteristics of each model become apparent.
Before we delve into the specific models, there is some technology that anyone shopping for a flash should be aware of. TTL is a term that will arise regularly when dealing with this type of equipment. It is an acronym for "Through-the-Lens," and is essentially how the computer embedded in the camera regulates the operation of the flash. It does this by sharing in-camera metering data obtained from metering off your subject through the attached objective. The camera activates and turns off the flash by measuring the light striking the sensor inside the camera; thusly the flash duration matches the camera's readings for proper exposure. It is a highly accurate system and does not require any external measurement tools to read light values such as a hand-held flash meter. Ultimately, this results in the ability to adjust the exposure on the camera, and if needed, fine-tune on the flash itself. As the metering systems inside cameras become increasingly more complex, the TTL language becomes more and more proprietary and may also become outdated. When buying a flash, make certain that not only does the flash "speak" the same TTL language, but make sure that the TTL generation matches your camera as well.
Another important ingredient is physical flexibility. A direct blast of horizontal light is not always ideal, especially when photographing people or objects with great depth. The quality of direct light is often more flattening than flattering. A good flash will have a range of pivot points to aim light on two axes. Like large format cameras, movements are named: vertical tilt on a flash is referred to as ‘bounce' while a vertical swing is called ‘swivel.' This range of motion is important when you want to modify, shape, reflect or soften the light falling on your subject for a more appealing effect.
Flexibility is augmented by the presence of a manual or automatic zoom head. Zoom mates the focal length of the lens used to the flash beam width and output. With some flashes the "focal length" of the flash is set automatically as you zoom a lens, others do not. Keep in mind that the flash zoom range is limited; on average it spans 24-105mm (in 35mm/full-frame standards). Wider focal lengths may require a spreader that is sometimes built-into the flash, or is available as an accessory. On the other hand, a longer lens may benefit from a modifier like a snoot or a device like the Better Beamer, a simple fresnel attachment that dramatically extends the reach of the light output.
When fine-tuning flash exposure or using a flash manually, adjustable output is necessary. Personally, I spent a few years of my photographic career with a camera set to 1/60 @ f/5.6 and ¼ power on the flash as I knew that the overwhelming majority of my subjects were at the same fixed distance from my camera. A lesser dedicated flash may not be capable of this range of manual control, so read the specifications carefully. Illumination is measured in the difficult to track guide number (GN) unit of measurement. GN denotes the light's farthest reach possible when a flash is set at a maximum while using a specific lens and set ISO. There exists a drastic problem when comparing guide numbers from flash to flash. While sourcing a GN for a flash unit, the photographic industry has not standardized the lens' focal length, aperture or is the ISO in use. Furthermore, GN is not an accurate representation of power, so it can get somewhat confusing while researching flashes. My recommendation is to use guide numbers as guidelines, and avoid using the figures as factuality.
Recycle time is an important factor in shooting situations where rapid sequences of images are made. Realistically, the majority of your shooting circumstance won't require shot after shot with a full-power flash burst, but the recycle times calculated are often based on full-power pops. Obviously, the faster times are better, and these times can be improved with an additional external rechargeable battery pack by Quantum , Lumedyne, Digital Camera Battery, and others. An added benefit is that the larger external cells also provide greater longevity, so instead of toting a dozens of disposable AA batteries, a single fully-charged battery pack may suffice. When shopping for external packs, consider ones using Nickel-Metal Hydride (NiMH) or Lithium (Li-Ion) cells rather than Nickel-Cadmium (NiCad) or Sealed Lead Acid (SLA) chemistry since often NiMH and Li-ion packs are newer designs boasting modern circuitry, while being infinitely more eco-friendly and recyclable. This rule of thumb applies to AA rechargeable and non-rechargeable cells as well.
Some of the flashes discussed are capable of being triggering wirelessly with a built-in component; which is another key point someone shopping for a flash should know. A dedicated wireless flash is unique as the electrical signal that triggers its activity does not come from direct contact with the camera's hotshoe nor a dedicated remote cord, but rather from an optical signal. An invisible burst of infra-red light from another flash can initiate a photoelectric circuit whereby a "master" flash may send a control signal to one or more "slave" flash receivers. The embedded TTL circuitry in each remote unit is capable of synchronizing with the camera which allows for exposure to be balanced for all of the dedicated flashes being used.
Rounding out a flash's feature set are some extras found on some of the higher-end units. These goodies include but are not limited to: stroboscopic bursts, a modeling light, a weatherproof design, a backlit LCD display, an accessory range, as well as a PC sync terminal. These may be overkill for some beginners, but they are tools one may grow into at a later date. So with the embedded technology explained, let's look at a selection of hotshoe mounted strobes for digital and film SLRs.
Beginning with the more professional and robust dedicated flash models from the camera manufacturers Canon, Nikon, Olympus, Panasonic, Pentax, and Sony, the 580EX II, SB-800, FL-50R, DMW-FL500, AF-540 FGZ, and HVL-F56AM respectively, are bestowed with features that carve out their place at the top of the heap. Examining the Nikon SB-800, the most prominent functions include four different wireless channels, the ability to function as a master or slave, manual mode, and vertical/horizontal bounce. The flash head is capable of covering lenses up to 24mm wide (full-frame/DX standard), and with a built-in wide angle adapter and included diffuser, it can go as wide as 14mm.
Canon's flagship flash, the 580EX II, is a powerful device with a bit more juice than the SB-800. It is also significantly larger. The comparisons pretty much end there as the Canon and Nikon interface languages are not cross-compatible; Nikon with Nikon, Canon with Canon etc. The 580EX II has rapid recycling, manual control and 14 custom functions. Another inclusion that makes this flash stand out is its dust and water resistance provided by the same type of seals that protect Canon's midrange and professional SLRs.
Panasonic has a premium flash, the DMW-FL500, that is fully compatible with the DMC-L1, DMC-FZ50 and DMC-FZ30 cameras and sports a full range of bounce and swivel movements and an automatic zoom head that couples with the camera. Wide-angle lenses are accommodated by the presence of a built-in panel.
Pentax's offering to the power-user is backwards compatible with their older 35mm & 120 film cameras' metering systems, yet has a set of specs that a Pentax digital SLR owner would be pleased with. The AF-540 FGZ has a high-speed sync for newer cameras, wireless TTL triggering with ratio control, four channels of trigger broadcast, and an illuminated LCD.
To complement the Alpha series of cameras, Sony produces the HVL-F56AM for their pro users. A special high-speed flash sync mode ensures that whatever shutter speed the camera is set to, the flash will evenly illuminate the entire frame. In the past, flash sync speeds were critical as exceeding the set speed would produce images that were partially underexposed with a strongly discernable line going across the frame. The HVL-F56AM also has the usual set of swivel, bounce and zoom movements for creative lighting options.
If your budget is tight, the more modestly-priced, Sony HVL-F42AM, Pentax AF-360 FGZ, Panasonic DMW-FL360, Nikon SB-600 or the new Canon 430EX II is suitable for most shooters. These second-string flashes are nearly the same size and roughly 1/3 less powerful than their varsity brothers. Aside from lacking a master wireless function (where applicable,) most significant features are also available on this junior series of units.
It is only when stepping down to the compact Pentax AF-200FG, Nikon SB-400, Sony HVL-F32X, Olympus FL-20 or Canon 220EX that the downscaling becomes pronounced. Part of the reason these petite flashes exist is for users who don't need to light up an entire room, but rather just a section of it. They aren't very powerful, but are substantially brighter than the pop-up flash found on the camera. Many lack the intricate manual controls, quick recycle times, wide system of accessories and directional light output. On the other hand, if the compact nature of an SLR was an important part of your decision in buying a camera, then you will want to retain as much of the compact form as possible. A 580EX II is nearly the same size as a Digital Rebel and when it is mounted in the camera's hot shoe, it is no longer the svelte streamlined camera that so easily fits in your hand. Not only are these smaller flashes easier to transport, but they also have TTL circuitry that allows them to work in a "look Ma, no hands" mode that is usually locked into fully automatic operation.
The brilliance of these multi-tiered offerings from the camera manufacturer themselves provides users with a flash for nearly every situation or level of photography. If criteria like budget, flash output, power source or compatibility preclude any of the aforementioned flashes, there are a host of portable lighting units from manufacturers like Sunpak, or Metz with their own variety of dedicated TTL flashes. Some with TTL capability admittedly do not work as well as flashes using TTL commands originated by the manufacturer of the camera you are using. Metz manufactures a range of flashes from simple dedicated unit like the 28AF– compatible with Canon, Sony/Minolta, Olympus/Panasonic and Nikon, to a powerhouse like the 58 AF-1 that is compatible with Nikon, Canon, Olympus/Panasonic, and Pentax/Samsung TTL systems. The Sunpak 383 is a perennial low-cost favorite and newer units like the Sunpak PZ42X or PZ40X II pack a decent number of professional features while remaining rather economical.
Additionally, Lumiquest, Sto-Fen, and Gary Fong (among others) produce a range of custom light modifiers to shape, diffuse or enhance the light output. These accessories easily attach to the full-size flashes, but in general, are not easily meshed with the lower-end compact units. Altogether, the best advice is to research and make a good prediction of your future needs when it comes to flash illumination. As a rule, it is nearly impossible to have too much flash as the output can be dialed down on the better flashes, and when a single flash burst is too weak, its output can be augmented by an array of wirelessly triggered and TTL slave flashes. So it is not unusual to regard your first flash as being the start of a future collection. Ultimately, TTL metering greatly improves and simplifies flash photography; now you can toss away the old slide-rule when calculating exposure and lighting ratios. Stylistically, a good flash is extremely versatile and can be used in a fashion that makes the additional light obvious to a viewer of your image. On the other hand, a flash may be used in a subtle or sculptural manner masking its presence to your audience. A final point to bear in mind is that a small sub-1 lb. flash unit can provide you, as a photographer, with a tool that puts you in control of your image– after all, that was one of the reasons you purchased an SLR camera with manual control of focus, aperture, ISO, and shutter speed. Lighting control is simply another element of image-making and is definitely the next step you should contemplate as your photographic skills develop.
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