Wireless flash is a highly effective tool that provides you with near-complete freedom to use your on-camera or studio strobes in any configuration to help you best achieve the lighting you desire. Wireless flash is, as the name states, a way for you to fire your flash or group of flashes remotely without having a physical, corded connection to your camera. This lack of a cord can benefit many situations, in addition to being a general convenience for a more expedient workflow. Additionally, a wireless flash system can still provide you with the same automatic functions as when shooting with a flash that is physically tethered to your camera, including TTL and master control functions.
While a hardwired flash can sometimes be preferred for reliability, wireless flash offers a range of possibilities that would otherwise be nearly impossible or incredibly difficult to accomplish by using a cabled connection. At the most basic level, wireless shooting frees up your workspace from cables themselves, which can often prove inconvenient or a hazard for subjects or yourself to negotiate. Especially when working with a flash off-camera, a cord connecting that flash offers an ideal obstacle that can result in knocked-over light stands and broken equipment. Wireless flash also gives greater flexibility when working with multiple light sources. Either by means of invisible or optical triggering, you can place flashes at greater distances and in more complex arrangements when you do not have to take into account where to place and run light cables. By removing the flash from your camera in general, nearly limitless lighting possibilities are available. The control over modification of the light, placement of the light, and the use of multiple lights when working is greatly benefited. This increase in freedom provides you with more room to experiment with different lighting setups and truly learn how to create the image you envision. If working in more confined, corded situations the flash can become more of a nuisance than a tool; if working wirelessly there are essentially no strings attached in regard to the options available for how to enhance the look of a scene.
The term wireless flash is an umbrella term referring to three different types of non-corded methods for triggering a flash: optical, infrared and radio.
An optical trigger, or optical slave, is the most basic means for wirelessly triggering flashes, as it requires no additional power and is an incredibly simple means for accomplishing a straightforward goal. These slaves contain light receptors that, once another flash has been detected, instantly trigger the flash they are connected to. Many current flashes contain a built-in optical slave and require no additional slave to be optically triggered wirelessly; however, if working with an older flash, a flash without an optical slave or for increasing the optical sensitivity of your flash, Wein offers a host of different options and connectors. One of their most popular slaves is the PN Peanut Slave, which features a convenient PC-connection type and supports optical triggering within a 100’ range. Offering a significantly greater range and sensitivity is the SSL Ultra Slave. This slave is available in both household and 1/4” mono plug connections and provides a 3000’ range for long-distance applications. It has a built-in ambient light filter to reduce accidental misfires from working in bright conditions and also has a female PC socket for greater connectivity. While limited in a multitude of features, these simple optical triggers can provide an ideal wireless triggering method for secondary flashes to be used in conjunction with a main flash that is connected to the camera by either a radio or infrared trigger.
Infrared triggering is similar to optical triggering with the exception that the receptor functions after detecting a burst of infrared light rather than a visible one. This is to say that an infrared transmitter still produces a burst of light to transmit its signal; however, there is a strong infrared filter in front of the light source that attenuates much of this light and converts it to an infrared signal. This is beneficial because you are not dependent on having a visible flash emanate from either your camera or a strobe directly wired to your camera; you can use a single strobe off-camera and wirelessly trigger it from anywhere. Like optical triggers, many cameras and flashes have built-in infrared slaves or transmitters, but the use of an auxiliary infrared system will often be much more sophisticated and powerful than those contained in your existing equipment. An infrared system functions best when working in indoor conditions or other situations where you have direct line of sight between the transmitter and receiver.
As with optical triggers, Wein makes a line of infrared slaves with both household and mono plug connections available. Both types also feature a female PC socket for a corded connection to your strobe. When working with infrared triggers, you will need to have both a transmitter and a receiver; similar to how a standard flash works as an optical trigger when working with optical slaves. These transmitters and receivers are available in two-channel or single channel configurations, with the two-channel option giving you the ability to use multiple flashes and only trigger certain ones depending on which channel is selected. Even though some flashes feature a built-in infrared receiver, a dedicated receiver will more often support this multi-channel functionality while also providing greater sensitivity for use at longer distances.
A radio slave is the most refined system of wireless triggering, as it requires no optical or visual sort of transmission and is entirely invisible. This allows you to trigger flashes without a direct line of sight, and often at greater distances than optical or infrared transmitters and receivers support. PocketWizard has long been a stronghold for radio slaves, and most of their units feature the unique quality of also being transceivers—a combination of both a transmitter and receiver within the same device. This allows for more versatility, as you can purchase several PocketWizards and use them on either multiple cameras or flashes to suit different situations. With the most recent introduction of the Plus III Transceiver, all current PocketWizard transceivers and transmitters now support 32-channel triggering for working with multiple groups of flashes or when working in crowded areas where other photographers are using radio triggers. There are also options available that work directly with either Nikon’s i-TTL or Canon’s E-TTL II systems; the FlexTT5 transceiver or the MiniTT1 transmitter. These function similarly to the Plus III, but with the inclusion of TTL compatibility, they are able to transmit exposure compensation information wirelessly between the flash and camera. Additionally, all PocketWizards are backward compatible with previous iterations of all PocketWizard radios, making them a sound investment for long-term use. Another viable option for wireless radios is the Impact PowerSync16 system. These radio slaves feature 16 channels to work with, and support flash sync speeds up to 1/250th of a second. The receivers feature the ability to be converted to use AC power, which is ideal for working indoors and does not require replacing batteries throughout use.
One of the more complex aspects of working with flash is how to properly set your exposure values, in regard to light output, for correctly rendering your scene. Flash is a variable that requires additional consideration for determining the proper exposure since it is not a type of light that can be constantly metered or easily previsualized. When working with manual flash, you are determining your camera’s aperture value solely by taking meter readings, working from guide numbers and revie
wing images in order to determine the proper exposure setting to flash power ratio. Working in this manner requires a bit more guesswork, as there are a number of factors that can affect how truea guide-number reading works, such as weather, surroundings and so on. On the beneficial side, manual flash does give you unlimited creative ability to over- or under-power your subjects with light or to create more complex multi-light setups.
TTL (through the lens) flash metering is equivalent to manual flash metering just like auto exposure is to general, ambient exposure metering. When working with TTL, your camera is able to determine a proper exposure setting that takes into account how bright your flash output should be, depending on where your subject is. TTL systems are often proprietary, such as Canon’s E-TTL II or Nikon’s i-TTL systems, so as to work cogently with your camera and similarly branded flash. Additionally, you can use third-party flashes with a paired TTL connection—either a TTL cable or a radio system with compatible TTL functionality. A TTL flash system utilizes a brief pre-flash to help acquire these exposure settings, but as such, if using an optical triggering method to link additional strobes, you will need to use slaves that can ignore or compensate for this pre-flash so as to not fire the flashes prior to the exposure being made.
Using your flash with manual settings wirelessly is a straightforward, although more difficult, means of using a strobe off-camera. It is more difficult in regard to the fact that you need to use a system, flash metering or testing, to calculate your exposure settings. It is simpler in nature, though, because there are fewer compatibility necessities and you have a broader range of options and methods to wirelessly tether your flash. When working with TTL metering in a wireless fashion, equipment compatibility is something that must be adhered to in order for everything to work seamlessly. Each camera manufacturer typically has their own TTL system that utilizes a proprietary coding or method to transmit and receive exposure calculations in order to properly balance your camera’s settings with the flash output. With this stringency accounted for, TTL and wireless flash afford you a number of options relating to convenience and efficiency that cannot be accomplished using a fully manual setup.
Wireless radio slaves most typically function from different channels, or frequencies, in order to communicate with the flash or the receiver attached to the flash. This benefit is twofold: it allows several photographers to photograph wirelessly in the same environment without accidentally triggering each others’ flashes and it allows you to set up different lighting schemes that you can transition to and from without having to manually adjust each unit. In addition to working on different channels, some TTL systems also support creating groups of flashes within a single channel. Groups can consist of one or more strobes that are all controlled by a master controller or commander. By grouping flashes, or several flashes within a single group, you can control the output levels of each of these groups when working with multiple light sources. An example would be to have your main lights set to one group, and your hair light, rim light, fill light or any other secondary light sources set to another group; this provides you with the ability to wirelessly control the light ratios between groups to fine tune the overall look of your scene.In order to utilize wireless TTL groups, you must use some kind of commander; either a master flash or a dedicated controller. This commander, if using an on-camera flash, will contribute to the overall exposure while also giving you the ability to modify the light output of the other lights in your group. A dedicated controller is a TTL-enabled radio or infrared unit that performs the same functions; however, it does not emit a flash and thus does not, itself, contribute to the lighting setup. The TTL settings, including the ability to alter light output levels amongst groups, are typically done through the camera’s menu system while the master flash itself is controlled through the flash’s own menu system.
Beside the PocketWizards previously mentioned, there are also commanders available from both Canon and Nikon that ideally suit their respective TTL systems. The Canon ST-E2 Speedlite Transmitter is compatible with a wide array of Canon’s Speedlites and supports full E-TTL and E-TTL II capabilities to an unlimited number of strobes. Two groups are available when using this transmitter, which provides more room to creatively engineer multiple light setups. The more-recently introduced ST-E3-RT Speedlite Transmitter is a radio transmitter that is specifically designed for use with the also recently introduced Speedlite 600EX-RT. When using the ST-E3-RT, you are afforded up to five groups with a total of 15 individual flashes for an extensive range of control over how your flashes perform. This transmitter, however, is currently only compatible with the 600EX-RT, due to its built-in unique wireless radio capabilities.
In regard to Nikon and its CLS (Creative Lighting System), there is the Nikon SU-800 Wireless Speedlight Commander. This wireless commander is compatible with many of the current Nikon Speedlights and supports control of an unlimited number of strobes within three separate groups. When paired with CLS-compatible cameras and flashes, this commander can provide wireless control up to 66’ and offers four independent channels for use amongst other photographers also using Nikon CLS devices.
Working with flashes wirelessly without the use of TTL can be a bit more freeing, but also more complex as you are the determinate of exposure settings. This begins to get more and more complex when working with more and more individual strobes and varying distances, but will make more sense once you become accustomed to creating and envisioning your own lighting situations. If TTL metering is not required, you can make use of “dumb” transmitters and receivers whose sole purpose is to tell a flash when to fire. When working in this manner you will need to either use a transmitter or a master flash that is connected to your camera, and subsequently some kind of receiver on each light source. The main purpose of this is to create a simple, straightforward connection between all aspects of your lighting setup and to have as few variables as possible in regard to the communication end. Once everything is linked, you are essentially ready to determine your exposure through a system of flash metering or through testing.
The initial intimidation of working with wireless flash stems from the fact that the lights themselves are out of realistic physical control and must be managed through alternate means. The benefit of working with either multiple flashes or even a single flash off-camera is that you gain more control and lighting options in regard to how you can modify the quality and overall look of the light output. By using either an intelligent TTL system or spending time getting to know your lights with manual controls, working wirelessly will immensely increase the range of scenarios you will be able to light in a much more efficient manner. Through the use of the proper tools and a working knowledge of how each works with one another, lighting can become more of a joy and a chance to be more creative with your photographs versus simply being a misunderstood tool used to only provide additional light.