Generic Flash Primer
This primer is part of a series of articles about using flash on a digital camera.
This segment addresses using so-called generic flash outside a dedicated framework, (i.e. non-TTL auto and manual flash, as well as non-dedicated off-camera flash).
Generic flash units are not compatible with the advanced dedicated flash control systems that are offered by Canon and Nikon. Instead, they provide a more basic functionality, but on many different systems.
While dedicated units are can have their power adjusted by a computer built into the camera, either through a wired connection to the camera body, or wireless by coded light signals, generic units are designed to fire when there is a (short) circuit between the flash's centre pin and edge.
As there is no dedicated control system for flash power control, the power output of generic units must be controlled by buttons and sensors on the flash unit itself. Most of the generic units offer at least manual (with adjustable power ratio) and non-TTL auto exposure modes.
For a list of models that can be used for generic flash, please consult:
- Recommended generic flash units.
- Generic flash units with Auto mode.
- Generic flash units with Varipower mode.
2. Exposure Modes
In order to have the scene properly lit, with correct exposure and with a good balance between foreground and background light, we need to control the amount of light put out by the flash, and adjust aperture, shutter speed and ISO to match that, as well as the ambient light. In this series, the following flash exposure control modes will be discussed:
- TTL automatic flash mode (i.e. Nikon's i-TTL and Canon's E-TTL) is only available on dedicated flashes. When you are using a TTL automatic flash mode, the correct power to use for flash is determined by measuring the amount of flash light reflected by the entire scene or foreground subject through the camera lens (TTL = Through The Lens).
- Non-TTL Auto flash mode (available on some dedicated and most generic flashes). When you use a non-TTL Auto flash mode, you use a built-in sensor at the front of the flash that measures the average flash light reflected by the entire scene.
- Manual mode (available on some dedicated and all generic flashes). When you use a Manual flash mode, nothing measures the light, you control exposure by setting up the power of the flash by selecting how much (as a fraction of maximum output) light the flash should emit, and selecting a ISO and aperture that will yield the right exposure.
Non-TTL Auto first appeared in the 1970ies and was the preferred method for controlling flash exposure until well after dedicated flash systems built around some form of TTL light measurement debuted around 1980.
In Auto mode (sometimes called Auto Thyristor mode), the flash is told what aperture and ISO the camera is set to, and a built-in sensor on the flash measures the average light reflected from the scene and uses a thyristor circuit to shut off flash power when the sensor indicates that the subject has received enough light for a correct exposure. The measurement is done in real-time, during the actual exposure. Unlike TTL, there is no pre-flash when you use Auto to control exposure.
Because the Auto-mode does not use pre-flash, the delay when you press the shutter button is shorter. The difference is small, but it may make a difference in responsiveness when you shoot sports with flash. Some people has fast enough reflexes to blink when they are exposed to the pre-flash. By using Auto-mode, you can photograph such people with their eyes open.
The exposure metering in Auto mode is simple and predictable when used for flash key (i.e. the flash is the main light). Most photographers learn how to compensate for the errors that the system introduces in difficult lighting situations.
For auto flashes with a head that can tilt and/or swivel, the sensor is placed on the body of the flash, never on the head. This means that as long as the flash is fixed to the hot-shoe, the sensor will measure reflect light along the same axis as the lens. The flash metering system will therefore automatically compensate for any light loss that is the result of (for instance) bouncing the flash light against a ceiling. But if the flash is used out of the hot-shoe, the fact that the flash sensor is no longer aligned with the camera may cause problems. For instance, if you put an auto flash inside a soft-box, the flash sensor will measure the light reflected inside the soft-box and not the light reflected from the actual scene. To get around this limitation, some auto flashes has a detachable sensor that can be mounted in the camera's hot-shoe while the flash can be put somewhere else.
Unless the flash is made to communicate with the camera (see below), to use an auto flash you need to set the camera up in manual mode (M). You then select a shutter speed equal to the camera's maximum X-sync speed or less, and a suitable aperture and ISO-value. You dial in the same aperture and ISO on the flash and you are ready to shoot.
Some flashes with Auto mode, the Canon 580EX II, and the Metz 54 MZ, are built to communicate with the camera through the hot-shoe, and automatically gets the aperture and ISO-value from the camera. In that case, there is no need to use M mode, you can also use P or A mode, and work with camera and flash just as tightly integrated as if you were using TTL.
Most other flashes of this type allow you to specify aperture and ISO through controls on the flash. Some very simple Auto flashes have only a limited set of fixed settings and require you to adjust aperture and ISO on the camera based upon a guide on the flash or a cheat sheet.
Unless the flash is made to communicate with the camera you dial in flash exposure compensation in auto mode by “lying” to flash it about what aperture you're using. However, if the flash picks up the aperture from the body you need to use explicit flash exposure compensation.
Some argue that modern TTL technology has made Auto obsolete. However, you can still buy cheap and powerful generic flashes using Auto for exposure control (e.g. Vivitar 285HV). Some dedicated flash units, such as Canon 580EX II and Nikon SB-910 also have an Auto mode.
When a flash is used in Manual mode, flash output power is not controlled by the camera (TTL) or by the flash (Auto). Instead, the photographer is in control.
Various manual modes exists, but the most common is a mode where the photographer controls the flash by setting a power ratio on the flash. The power ratios are usually displayed as fractions: “1/1” is full power, “1/2” is half power, and so on.
Not all manual flashes let the photographer set a power ratio. In that case, assume that only a single power ratio (1/1) is available.
After deciding on what power ratio to set on the flash, the photographer need to determine what aperture to set on the camera for a correctly exposed scene. The aperture need to match the power of the flash.
The simplest way to accomplish this, is to use a handheld flash meter (e.g. Gossen Digiflash – search for this product: Adorama, Amazon USA, Amazon UK, B&H, eBay). Fire off a test flash, meter it, and the meter will tell you what aperture to use.
If you regularly shoot complex lighting setups with one or more manual flashes, I strongly recommend that you use a flash meter. With a flash meter, you can meter any setup with all your lights in place and set up with appropriate power ratios. After metering the test flash there is no need to make another reading until you rearrange the lights. A flash meter will work with a multiple flash setup, bounced flash, and all sorts of light modifiers (e.g. brollys and soft-boxes).
If you don't have a flash meter, it is possible to compute the aperture to use from ISO, distance from flash to subject, and the flash's Guide Number (GN).
The GN is usually only given for ISO 100, and is always tied to a unit of measurement (meters or feet), To convert a guide number from meters to feet, multiply it by 3.3. To convert a guide number from feet to meters, divide it by 3.3.
Note that if the flash has a zoom head, or a Fresnel lens that may be used to focus the beam, the GN varies with the position of head or lens. Refer to the manual to find the GN at the zoom setting you're using.
To work out the aperture to use at ISO 100, simply divide the GN with the distance from flash to the subject. i.e.:
Aperture = GN / distance from flash to subject
For example, at ISO 100 for a flash with a GN of 40m (meters) at full power, and the main subject 7 meters away, you get 40/7=5.7. Round this to the nearest available aperture, in this case f/5.6. This is the aperture you set on the camera.
If you are shooting at a different ISO value than 100, you multiply the guide number at ISO 100 with the square root of the ISO value divided by 100 to obtain a revised guide number. For instance, if the flash has a GN=40m at ISO 100, at ISO 200 the guide number becomes 40 x SQRT(200/100) = 57m. If you still are 7 meters from our subject, you get 57/7=8.1, and the nearest available aperture is f/8.
Guide numbers are not much used these days. Most photographers prefer to use a flash meter when working with manual flash. But back in the 1970ies, when working photographers still used guide numbers on a regular basis, most photographers used pre-computed guide number tables to show what aperture to use at various distances and ISO-values. The image to the right show such a table. It is from the back of a Prinz Jupiter 2000 flash from 1973 which has a guide number equal to 18 (meters) for ISO 100/21° (known as “ASA” and “DIN” in the 1970ies).
The guide number is still useful if you want to work out the reach of a flash – including the reach of non-manual flashes. In that case, divide the guide number of the flash at the ISO you are shooting with the f-number you plan to use. The answer is the maximum flash to subject distance.
For example, if your flash has a guide number of 40 (meters), and your aperture is f/2, maximum flash-to-subject distance for correct exposure is 40/2 = 20 meters.
If the flash let you set a power ratio, the guide number is reduced by the square root of the ratio you set. For example a flash that at full power has a guide number equal to 40 has at half power (power ratio 1/2) a guide number equal to 40 x SQRT(1/2) = 28.
Similarly, you can get more power by using more flash units. Adding another identical flash doubles your light output, which is equivalent to adding an extra stop of light. In terms of guide numbers, the combined guide number of multiple flash units is the square root of the sum of the squares of the guide numbers for the individual flashes. For instance, if you are using four flashes with individual guide numbers equal to 18, 26, 34 and 38, the sum of squares is 18x18+26x26+34x34+38x38=3600, and the square root of 3600 is 60. I.e. the combined guide number of firing four flash units in tandem is 60.
If you do not want to do the math yourself to find out the the GNs for different varipower and ISO settings, you may want to use our guide number calculator.
To work out the aperture to use for manual bounce flash against a white ceiling, first compute an aperture by dividing the flash's guide number with the total distance the light has to travel (i.e the distance from the flash to the reflecting point in the ceiling, plus the distance from the reflecting point to the subject). Then open up at least two extra stops to compensate for light being absorbed by the ceiling. Check the histogram to determine if the exposure is correct, and adjust if necessary.
For manual fill flash, increase the shutter speed until the background is properly exposed. To lessen the effect of the flash on the foreground you may dial down the light output using a suitable power ratio, increase the subject to flash distance, or use light modifiers such as diffusers.
3. Off-camera Flash
For working with multiple off-camera flashes, the dedicated wireless flash control system from Canon or Nikon will often do the job. However, dedicated flash units are expensive, and the built-in flash on most of Canon's DSLRs (except EOS 7D, 60D and 600D) can not be used as commander in Canon's wireless control system. The built-in flash on Nikon's entry level DSLRs (such as D60 and D5000) have the same limitation. If the camera's built-in flash can not be used as commander, you also need to buy dedicated wireless transmitters (ST-E2 or SU-800) or an extra dedicated flash unit to control off-camera flash.
In addition to the additional cost of using dedicated flash units, there may be situations where the manufacturer's dedicated system for off-camera flash do not work well.
For instance, when you want greater range, when you are working in a mixed setup where you want to use you dedicated units together with generic flashes or monolights, or in some other environment where it is not possible to use a dedicated system for wireless control, or when you are using a manual lens, you probably will want to use generic wired, plain optical and/or radio off-camera flash instead.
Because generic off-camera flash doesn't involve a pre-flash, you can freely mix all three means of communication. For instance, you can put a radio transmitter on the camera as master, and use this to trigger a few strategically positioned slaves units with a radio receiver. The light from these will then trigger other units fitted with optical receivers. Units in close proximity to each other can be connected to the same optical or radio receiver by wires. By doing it this way, total cost is kept low, and at the same time the photographer can move around freely because no wires attach the lighting to the camera. However, flash units from different manufacturers often have different colour temperatures. Mixing several brands may lead to problems with colour casts.
This section discusses using non-dedicated off-camera flash (by some also called “strobist”-style flash). For dedicated solutions for off-camera flash, see the sections dealing with Canon and Nikon respectively.
“Strobist”-style has become synonymous with using multiple small battery powered manual flashes that are wirelessly triggered (by radio or light). The name is derived from the popular blog Strobist.com, where Baltimore based photographer David Hobby champions this type of flash use (as opposed to using automatic, dedicated TTL flash units, mono-lights or studio lights).
Generic Wired Flash
For multiple off-camera flashes, you can connect several units to the camera or to other flash units by means of a multi flash pc adaptor like the one shown on the right.
For multiple off-camera flashes, Nikon used to offer a wired solution designed to work with OTF TTL. This system used a special 3-pin connector that you'll still find on the SC-17, SC-28 and SC-29 off-camera shoe cords. Each of these cords ends with a cube with a Nikon hot-shoe on top and two 3-pin terminals on each side that let you connect two additional Speedlights by so-called TTL Multi-Flash Sync Cords The Nikon models number for various lengths of these cords were: SC-14, SC-18, SC-19, SC-26 and SC-27.
To fan the signal out to more than three Speedlights, you would use the Nikon AS-10 TTL Multi-Flash Adapter. This is a cube with three Nikon 3-pin sockets and a hot-shoe on top. The photo on the left shows a copy of the Nikon AS-10 made by YongNuo.
The “TTL” in the name of all these products refers to Niko's pre-CLS TTL systems that used a quench signal to control the power of Speedlights. It is not in any way compatible with Nikon CLS or the current i-TTL system.
However, you can still use these connectors and cords if you operate legacy Nikon Speedlights fitted with a three-pin connector in the manual and non-TTL auto modes.
For example, to use a three flash wired setup using Nikon SB-800 Speedlights, first take one flash off camera with the SC-28 off-camera shoe cord, and then tee off two more SB-800 Speedlights by connecting them with the SC-19 to the 3-pin contacts on the SC-28. All three Speedlights will now sync with the camera, but in manual and auto modes only.
It is also possible to remove the Nikon 3-pin plug from one end of these legacy cords and replace it with a 3.5 mm mono-plug or pc-connector to fire non-Nikon flash units with a suitable external terminal socket.
Whether you use pc-cords or Nikon's legacy cords, a wired set-up for off-camera flash restricts your positioning of remote units to the physical length of the cord, and also entails the hazard of tripping over the cords. Also, when you connect one or more units to the electronics of your digital camera with cord, trigger voltage safety may be an issue. Therefore, many photographers prefer to use wireless solutions using light or radio signals to trigger the remote flash.
Plain Optical Slave Triggers
A plain optical slave trigger is an electronic device that will trigger an off-camera flash when it “sees” another flash fire. You can buy cheap plain optical slave triggers and attach a compatible flash unit to it to create an optical slave flash. (To learn about about the combinations to avoid, see our notes on incompatibility.)
Some flashes have a built-in optical trigger (e.g. Nikon SB-910 and most monolights) that will trigger the flash when it “sees” another flash fire.
However, to use the light from the camera's built-in flash to trigger remote units, you need to prevent (or make the remote units ignore) the pre-flash. Otherwise, the pre-flash that is intrinsic to dedicated flash systems will ruin your shot by setting off the optical slaves before the shutter opens. How you can do this is described in the next section).
If you don't want the master flash to contribute light to the exposure, dial down the power ratio as far as it will go without making your slave flash(es) unreliable. If you want to reduce the master flash output without affecting the range, you can make a makeshift IR-pass filter by taping black unexposed E6 slide film in front of the master flash.
You should not mix TTL exposure control with plain optical slave flash. In this kind of setup you should use both the camera and all the flash units involved in manual mode. Refer to the sections Auto and Manual to learn how to control exposure in these modes.
Not all optical slave triggers work well with all flash units. See our notes about incompatibility to see what problems you need to look out for.
Preventing pre-flash, etc. from firing slaves
When using plain optical slaves (i.e. a setup where the flash on the camera is used as master to trigger one or more slave receivers that are programmed to fire when they see the light from the camera flash), the slave flash must fire after the shutter opens. If it fires too early, it will be unready when needed to light the scene.
Some cameras strobes the on-camera flash to assist the camera's autofocus system in dim conditions. This will trigger the optical slave prematurely. If your camera does this, you need to disable AF-assist to use plain optical slave flash.
Also, the pre-flash that is at the heart of a dedicated flash control system must be prevented from firing the slave flashes.
How you do this depends on your camera's make and model.
Some Canon cameras, such as the compact Powershot G5, EOS 7D, EOS 60D and EOS 600D let you set manual mode (M). This turns off pre-flash. Note that this also disables E-TTL. See the camera's manual for details (e.g. p. 101 in the Powershot G5 manual). However, most Canon DSLRs do not have a manual flash mode.
On a Nikon camera, you disable pre-flash by selecting manual flash mode. Note that this also disables i-TTL. NB: Do not use the manual setting in Nikon's commander mode. It will not work.
As far as I know, you cannot set the built-in flash on most Canon DSLRs to manual. Below is a list of alternative methods that may be used instead to prevent slaves prematurely:
- Attach an external flash unit to the hot-shoe. You can either use a generic flash, or you can use a dedicated flash set to fully manual. Do not use the manual setting in any commander or master mode, as this will result in the master firing pre-flashes. NB: Not all dedicated flash units offer a fully manual mode.
- Attach an external flash to the camera's pc-connector instead of from the hot-shoe. To use this method, both camera and flash must have the appropriate connector, or you need an adaptor.
- Use a radio system to control the remote flash units.
- Use blank FEL or blank FV lock to fire the pre-flash while covering the flash head in tin-foil or similar).
- Use a special slave flash with a built-in “digital smart” trigger that can be set to ignore pre-flash, or an external slave flash trigger with this capability. I do not recommend this, as noted here, these are not very reliable.
Blank FEL and Blank FV Lock
The technique known as blank FEL (Canon) or blank FV lock (Nikon) is a way of preventing the pre-flash from affecting slaves controlled by plain optical triggers.
This is most useful on those Canon DSLRs where there is no straightforward way of disabling pre-flash, but you can, if you want to, also use this technique on a Nikon DSLR.
Here is a step by step recipe for blank FEL or blank FV lock:
- Make sure the built-in (dedicated) flash is popped up and ready.
- Cover the flash completely (e.g. with your hand, tin foil, or a dark cloth).
- Push and release the button to lock flash exposure (FEL/FV lock). The pre-flash will be emitted, but should not trigger the slave flashes.
- With Canon, you now have about 16 seconds to shoot your picture. With Nikon flash exposure is locked until you push the button a second time.
- Uncover the flash, and depress the shutter button fully to take the picture.
Note that not all DSLR cameras have a dedicated FEL/FV lock-button. With some models, you need to assign this function to a programmable button first.
For more details, and some variations, see Julian Loke's note on blank FEL.
Mixing Dedicated and Generic Wireless Flash Units
People that own a combination of dedicated and generic flash units sometimes want to use all the units they already own at the same time to light a scene. I.e. for frugal, or other, reasons they want to use a mix of generic and dedicated flash units in a particular setup.
If you want to do this, the simplest way to do accomplish it is to “dumb down” your dedicated units by disabling all advanced features such as i-TTL and AWL (Nikon), or E-TTL II and dedicated wireless control (Canon). Instead, you use pc-sync cords, cheap radio triggers and optical triggers to fire the off-camera flash units.
If you use optical triggers, make sure that you prevent pre-flash from firing the slaves prematurely. I.e.: Switch everything over to manual and operate the combo by treating all the units involved as generic flashes.
However, there may be situations where you want to retain dedicated functions such as TTL control of on-camera and remote flashes, and at the same time fire off generic wireless slaves in manual mode. If you want to try this, here are some suggestions to help you along:
- There now exist remote triggers that are designed to let you combine TTL with manual flash. Such units include the Phottix Strato, Ojecoco H-550 and Pixel Knight. The Phottix Strato and Ojecoco H-550 features a TTL pass-through hot-shoe that allows you to piggyback a TTL wireless controller (e.g. a Canon ST-E2 or a Nikon SU-800) in the hot-shoe of the radio transmitter. The Pixel Knight let you combine a single wireless TTL group with one or more manually controlled groups.
- Use the dedicated optical system (Nikon's AWL or Canon's wireless E-TTL mode) with a dedicated master flash in the hot-shoe to trigger dedicated remote flashes. Then, connect any radio slave trigger to the camera by means of the the camera's pc-connector, and use radio slave triggers to fire the generic wireless slaves. Some cameras may not have a pc-connector, or may disable the pc-connector when there is a dedicated flash in the hot-shoe. You can get around this by using a hot-shoe to pc adaptor with an extra hot-shoe on top.
- If you want an optical solution, the fundamental problem you run into is that the pre-flash that is intrinsic to dedicated flash will trigger any plain optical slave prematurely. As a workaround, you can lock exposure well ahead of the actual exposure by using FEL (Canon) FV lock (Nikon) to introduce a delay between the time flash exposure is measured, and the time the actual exposure is performed. Your plain slaves will fire when you press the FEL/FV lock-button, but by introducing a delay, they will have time to recharge and therefore be ready to fire again when you press the shutter button. See your camera's manual for a description of how you activate FEL or FV lock.
- As an alternative to using FEL/FV lock to create a delay, you may try to use so-called digital slave triggers that that can be set to ignore the pre-flash. However, while some of these devices cope reasonable well with TTL-mode pre-flashes, they may not be advanced enough to also work with the additional commander-mode pre-flashes. I currently know of no such device that works reliable in commander-mode.
Note: Mixing dedicated and generic flash means that the sophisticated exposure logic that is at the heart of any dedicated flash systems will not “see”, and therefore not be able to take into account, the light thrown by the generic units in the mix. This may, depending of circumstances, throw the dedicated exposure control system off track.
But, for example, when shooting a venue that takes place in a large room, it often works well to have radio controlled manual flash units positioned hidden from direct view around the room to fill in the background. These should be positioned to not throw any light on the main subject (e.g. the people in the foreground). Which such a set-up, you can use TTL to control the key light that illuminates the foreground, including any people there. Using TTL means that the photographer can move quickly in close for portraits and back off for groups, leaving control of the strength of the key flash to the automatic logic of TTL.
Radio Slave Triggers
Optical solutions for off-camera flash of both the dedicated and plain variety struggles outdoors, especially in bright light. Optical units also require a clear line of sight between master and slave.
For this reason, many instead opt for radio transmitters to control off-camera flash units. Radio will work outdoors in bright light, and requires no line of sight between master and slave.
The downside of radio is cost. Quality radio systems, (e.g. Pocketwizards), are expensive, but in later years, several low cost alternatives have become available.
The low cost radio slave triggers does not support TTL exposure control. In this kind of setup you must use the camera in manual mode. You control the power of the flash by using non-TTL Auto or Manual power control.
You may not always want to connect the flash to the camera's hot-shoe. For example, if you want to trigger the flash from a generic optical or radio-controlled wireless trigger, you may want to connect the flash through the pc-socket rather than a hot-shoe. Most generic flashes will work if you mount them in the hot-shoe. However, because of the hazards associated with high trigger voltages you should be aware of the risks involved. Connecting them through a pc-connector may be safer. Refer to your camera's manual for details. Another situation where you want to connect your flash through the pc-socket instead of through the hot-shoe, is when you don't want any of the dedicated TTL functions found on modern cameras to interfere with your flash
If the flash comes fitted with a pc-socket, you just run a cable from the pc-socket on the flash to the pc-socket on the wireless trigger or camera.
If your flash does not come with a pc-socket, you can buy a pc-to-hot-shoe adaptor, such as the model displayed on the right, to make the connection. You then use a standard pc-to-pc cable to connect the adaptor to the trigger's or the camera's pc-socket, and mount the flash in the hot-shoe of the adaptor.
Dedicated flashes built for a different camera system than what you are using will in many cases not fire from the hot-shoe, but may work fine in manual mode if they are connected through the pc-socket, or – if they are not fitted with a pc-socket – through a pc-to-hot-shoe-adaptor.
If your wireless trigger has a 3.5 mm monoplug-socket instead of a pc-socket, FlashZebra offers a monoplug-to-hot-shoe adaptor.
I find 3.5 mm mono-plugs more reliable than pc-sync sockets, so I've opted for the 3.5 mm monoplug to hot-shoe adaptor shown below to trigger flash units that only has a hot-shoe connection. The image on the right shows the adaptor with the rear wall removed, so you can see the internal wiring. The adaptor is actually a Seagull slave cube that has been rebuilt to serve as an adaptor.
Canon's higher end DSLRs (e.g. EOS 10D, 20D, 30D, 40D, 50D, 5D-series, 7D, 1D-series) comes with a pc-socket, that can be used to trigger generic auto and manual flash units. The maximum safe voltage rating for the pc-socket can be found in your camera's manual. For all current models, I believe it is 250 volts.
Nikon's higher end DSLRs (e.g. D200, D300, D700, D2-series, D3-series) comes with a pc-socket, that can be used to connect most generic auto and manual flash units. The maximum safe voltage rating for the pc-socket can be found in your camera's manual. For all current models, I believe it is 250 volts.
Most compact cameras and some entry level DSLRs do not have a pc-connector. For these cameras, a possible workaround is to use a hot-shoe-to-pc-adaptor in the camera's hot-shoe.
Pixel makes hot-shoe to pc-adaptors (generic version for ISO 518 hot-shoe shown on the left). The Nikon and Sony versions pass through the TTL signal from the camera to the hot-shoe on top of the adaptor. This means that you can connect a generic flash by means of the pc-socket, and have a dedicated flash mounted in the adaptor's top hot-shoe. The series includes TF-321 (Generic – do not pass through), TF-322 (Nikon i-TTL pass through), and TF-323 (Sony/Minolta P-TTL pass through). According to this thread on Flickr, you can add pass-through to the TF-321 if you know how to solder.
With a hot-shoe to pc-adaptor, you can connect the pc-plug of a sync cord to the adaptor's pc-socket. Since the adaptor is plugged directly into the camera's hot-shoe, you should only do this if you know that the flash is trigger-voltage is safe.
For wireless off-camera use, you can use plain optical or radio slave triggers to fire generic flash units. Using slave triggers also removes any trigger-voltage worries, because the third-party flash is never in physical contact with the camera, only with the optical or radio slave trigger.
6. Flash links
- David Hobby:
- Strobist (Great blog about Nikon flash use and lightning in general by Baltimore based photojournalist David Hobby.)
- David Hobby:
- Strobist: Lighting 101 (Good tutorial on using off-camera flash.)
- David Hobby:
- Strobist: On assignment (Examples of clever use of off-camera flash.)
- Joe McNally:
- Blog (Photojournalist and author of several books about creative flash use.)
- Neil van Niekerk:
- Flash Techniques (Tutorial on flash photography for weddings and portraits.)
- Home Page (Supplier of custom made cords, slave triggers and other flash accessories.)
- Lighten up and shoot (Blog aiming to teach photography and lighting with a little humour.)
- Lighting essentials for photographers (Web site about flash, studio lighting and natural light.)
- Portrait Lighting:
- Home page (Web site and blog devoted to studio lighting for portraits.)