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Topic:	Automotive Lighting 6: Selecting Flash equipment
Author/Copyright:	John Jovic

There are many different kinds of flashes which can be used for photographing cars. Your particular needs or style of photography will therefore drive flash equipment choice. Possibly the only common factor amongst all the suitable options is that the flashes used for car photography are normally positioned carefully around the car being photographed, ie 'off-camera'. The flashes generally have no reason to communicate with a camera, other than to know when to fire, so there is no reason to use dedicated or proprietary wireless flashes from the same company that made your camera. Almost any flash is fine for static car photography (see warnings about Trigger Voltages below) as long as it suits the way you want to work and your budget. Dedicated flashes are handy for simple fill flash such as when photographing people, a car show or event, but have relatively little practical application for static car photography.


A barrage of Monolights is used here to create smooth tonal gradation in the side of the car being photographed. This kind of flash equipment is great for a studio but quite cumbersome in the field.		Portable, battery powered strobes are ideal for location car photography. Note the lack of light modifiers such as softboxes, brollies etc. which can be counterproductive in car photography.

For those unfamiliar with some of the terms used to describe electronic flash there is a brief definition of terms at the bottom of this page.

Flashes or strobes fall into a few broad groups and not all of them are well suited to car photography. The descriptions below are generalizations as it's not possible to explore the details and specifications of every brand and model of lighting on the market.

Mains powered Monolights or Power Packs (also called Floor Packs)	Mains powered strobes are the strobes typically used in studios or in environments where mains power is readily available. They are typically the most flexible and powerful strobes but their physical size and practical constraints such as power cables can make them difficult to use on location. Some strobes are fully self contained and are called Monolights. Monolights tend to be bulky because they enclose everything that they need to work. All you have to do is plug them into mains power. Another common style of strobe lighting is to have a Power Pack, which is connected to mains power and houses the bulk of the electronics, then smaller Flash Heads are then connected to the Power Pack itself. These systems allow much smaller Flash Heads and greater versatility and power output but tend to be very expensive and their Power Packs are often very large, heavy and generally need to be quite close to the Flash Heads themselves. Elinchrom, Bowens, Broncolour, Hensel, Norman, Profoto, Visatec Paul C. Buff (AlienBees/Einstein) are just a few of the major suppliers of the kinds of lighting equipment described above.
	Pro's	Con's
	Powerful and with very fast recycle times. Flexible, can be used with a large range of attachments such as soft boxes, Fresnel spots, Ring flashes and light modifiers. Consistent and repeatable colour temperature and light output. Tungsten Modeling lights are standard in most mains powered units and they allow you to see the effect of the strobes as you adjust them. Built in slaves. Some have built in radio receivers such as PocketWizards. The most powerful strobes available are Power Pack systems.	Heavy and often physically large. Expensive. Can be cumbersome to use because of the cables needed to connect them to Mains power. These cables will also tend to be reflected in the panels of a car so hiding the cables can also be problematic. They may need a generator or Inverter to be able to use them outside of a studio or away from Mains power. Monolights can blow fuses on a mains power circuit if too many are connected to the same line. This is a particular problem with high powered Monolights, eg over 1000WS. Once the fuse is blown you may not have access to the fuse box to repair/replace it!
Battery powered Monolights or Power Packs For example; Elinchrom Ranger RX Elinchrom Quadra RX Lumedyne Bowens Gemini etc.	Battery powered units are by far the most useful and practical for car location photography. Many of the Monolights mentioned above can be powered with Inverters which are run from a battery, often a 12 Volts Sealed Lead Acid Battery (SLA). There are also battery powered versions of many of the strobes mentioned above. These usually have their own Power Pack, just like a mains powered unit, but it is run from an internal rechargeable battery. These units are usually quite powerful, often have replaceable batteries (so you can have spares with you) and some times even have modeling lights. Elinchrom, Lumedyne, Bowens, Broncolour, Hensel, Norman, Profoto are just a few of the major suppliers of the kinds of lighting equipment described above. The Einstein from Paul C. Buff is a fairly compact mains powered Monolight which can be run from a very compact Inverter (Vagabond Mini Lithium). If one Inverter is used per Einstein then this makes a fairly compact unit without the problem of mains power cables running along the ground.
	Pro's	Con's
	Can be powerful and with very fast recycle times. Flexible, can be used with a large range of attachments such as soft boxes, Ring flashes and light modifiers. Consistent and repeatable colour temperature and light output. Some have modeling lights. Some have built in slaves.	Heavy and often physically large. Expensive. Can be cumbersome to use because of the cables needed to connect the flash to the Battery Pack itself. These cables will also tend to be reflected in the panels of a car so hiding the cables can also be problematic. Battery packs and spare batteries can be very expensive. Although they are often quite powerful their useable battery life is determined by the power of the flashes attached so high powered flashes lead to a shorter battery life. Using modelling lights drains batteries very quickly. They are not as powerful as mains powered Power Packs with Flash Heads.
Speedlights, 'Hotshoe' or bracket mount flashes (intended for use on camera) For example; Canon 580EXII Nikon SB-24, 26 etc Metz 54's, 60's etc Vivitar 285's etc	Battery powered hot shoe mounted flashes, or flashes attached using a bracket, are by far the most useful and practical for car location photography on a budget, although, they should probably never be used on the camera itself. These units are often very cheap and depending on your requirements can have enough power for many kinds of car photography. The types of units referred to are those such as Canon 580EXII, Nikon SB-26, Metz 54's, Vivitar 285's etc.
	Pro's	Con's
	Relatively fast recycle times, often a couple of seconds. Can be very cheap. Usually very small and light so they are very convenient in terms of where they can be positioned, such as in engine bays. Their small 'footprint' also makes them easy to hide in a cars reflection. Potentially disposable due to low replacement cost. They usually use commonly available and cheap AA batteries. May have HSS (High Speed Synch) or other proprietary systems allowing the strobe to synch at abnormally high shutter speeds.	Low to moderate power and hence limited application. Can't be used with many light modifiers which have the effect of reducing light output even further. No modeling lights. No built in slaves (except Nikon SB-26, maybe others?). It's easy to forget that you left one under a wheel and then have the cars owner move the car and run over your flash. Ask me how I know that...
Dedicated flashes, eg. Canon, Nikon	Dedicated flash systems such as iTTL, E-TTL and the proprietary wireless systems from Canon, Nikon and others are great for their intended purposes but are not so useful for static car photography. Dedicated flash systems are great for on camera use at car events or car shows where they are great for getting excellent fill flash exposures. Several companies makes flashes which simulate dedicated units from Canon, Nikon and others. These are a great option in that they often use an adapter which allows the same flash to be used on several systems, just by replacing the adapter, not the whole flash (check manufacturers specifications).
	Pro's	Con's
	The same as above. Excellent for fill flash applications such as when shooting people, car shows or events. High end flashes often have functionality allowing the unit to synch with the camera at speeds beyond the cameras maximum flash synch speed.	The same as above. These are generally the most expensive flash units as they are often the latest model and most sophisticated. Dedicated flashes are not useful for static car photography as the flash is normally used in manual mode.

Older or very simple manual flash units are fine for off camera work. The speed and practicality that comes with small units can make them a better choice than larger units which might need power cables to run them. Larger battery powered units such as Bowens, Elinchrom, Lumedyne, Profoto, Balcar and others are all fine but the size, weight and cost of these units puts them in another category of lighting equipment. As long as the units are powerful enough for your needs, reliable and suit your way of working then it really doesn't matter which kind flash you use. The greatest limitation with using small flashes is their power. You simply can't use large soft boxes and expect a decent amount of light from them unless your flash is quite powerful to start with. If this is how you like to work then larger and much more expensive strobes are the only way to go.

There are many qualities which differentiate high end flash equipment, such as flash duration, colour temperature control or accuracy, recycling speed etc. These are all potentially important factors but they do come at a cost and often you need to decide how important some of these qualities are to you and your specific application. If you can wait 8 seconds for the flash to recycle then that might save you a lot of money, but a people/fashion photographer almost certainly couldn't.

A few observations about small/inexpensive strobes or speedlights

Being the most commonly used form of off camera lighting for car photography it's worth looking at some of the quirks of small portable strobes such as hot shoe or bracket mounted flashes.


You can certainly achieve worthwhile results with simple and inexpensive strobes. These are a good starting point for any one new to car photography.		Small flashes with radio slaves are some times the best way to solve a lighting problem but of course they have limited power. Radio slaves solve the problem of synch cables getting in the shot.


Output Power	The flashes you choose need to be powerful enough for the way YOU intend to work. If you want to use soft boxes, brollies or large light modifiers then forget about small strobes, at least for car work (but you might have enough power for close range portraits or detail shots, engine bays, interiors etc). Photographing cars with small strobes tends to be quite easy as it's quite common to use the strobes without any light modifiers so you don't loose any of the strobes power. None the less, your specific way of working will determine the gear you will need. If you regularly use polarizing filters with flash then this will effectively reduce the flashes power by about 1.5 stops. If you tend to shoot at F8-11 and at ISO100 (Canon), compared to ISO200 which some Nikon cameras use as a base ISO, then that's another stop needed that the next person, a Nikon user, might not. It's also generally better to have more power then you need, rather than less, so err on the side of caution.
Output Power Control	The main practical requirement of any flash unit is that it has manual output power adjustment. Flash units which only operate at full power or on Auto settings are of very little use. The best kinds of flashes are those that allow the output power to be adjusted in fine increments, such as 1/3rd steps, all the way from full power downwards. Some flashes have very course output power adjustment such as a full stop between each setting. These can be OK but they will always be a bit slower to get just right as they may need to be repositioned to achieve in between power settings or possibly have diffusing or ND (Neutral Density) gels added or removed. Flashes such as the 580EXII and Metz 54's and 60's have 1/3 power adjustment and are quick and easy to use. Some of the Nikon flashes, such as SB-28 (and similar vintage) have a single step adjustment from full power to half power and then 1/3 increments after that. This might be because the fine adjustments, on Canon and Metz flashes mentioned above, are rarely accurate in the full-half power range but tend to be more accurate at lower power settings.
Trigger Voltage	The trigger voltage is the voltage which the flash applies to the cameras contacts, be it the 'PC contact' (usually on the front or side of the camera body) or the 'Hot Shoe' (the flash socket on top of the camera). The trigger voltages of flashes vary from a few volts to a few hundred volts and are normally specified by the flash manufacturer. Your cameras manual will specify the maximum trigger voltages your camera is designed to handle. You can damage your camera by using a flash with a trigger voltage higher than that which the camera is designed for. If the trigger voltage of the flash is higher than the voltage your camera is designed for then do not connect the flash to the camera without an adapter designed to reduce the flashes trigger voltage to a safe level, usually a few volts.
Recycling speed	Flashes which recycle quickly are generally more convenient to use than flashes that take longer to recycle. You will normally be limited by your slowest flash as that's the flash that you will always have to wait for. Another consideration, or at least some thing to be aware of, is that some flashes will fire even if they are NOT fully charged whilst other flashes will only fire when they are at full charge. A Nikon SB-28 fires pretty much any time the (tiny, near microscopic) test button is pressed, regardless of the state of charge, whilst a Canon 580EXII only fires at full charge. This can lead to inaccurate exposures if flashes are firing at different rates of charge. It's worth testing your flashes to at least be aware of any possible problem.
Battery	Most flashes use AA batteries but some older flash units can use batteries that are either expensive, hard to get or both. The Metz 60 is an example of the above. It uses a special version of a Sealed Lead Acid battery which is quite expensive and needs to be replaced every few years.
Colour Temperature	The colour of the light emitted by a flash can change or vary for several reasons. There are differences between brands, differences due to the power setting used on the flash and some times differences caused by the age or wear on the flash tube itself. The colour temperature of most flashes will be in the same 'ball park' and will not really matter but if you use 2 different flashes with different colour temperatures then they may stand out as having a different colour light if they are used together to light adjacent parts of a car or subject. It's a good habit to use identical brand/model of flashes to light the side of a car if using 2 flashes. That way the colour temp of those 2 flashes will probably be quite close and not cause a problem.
Reliability	Buy a good flash once, not a bunch of cheap flashes over and over again because they break, fail, wear out etc. Nikon and Canon make very robust flashes and their prices on the used market can be very reasonable.
Connectivity	Not all flashes have a PC socket built into them as standard however PC sockets are usually required to connect the flash to a PocketWizard or slave sync. If your flash doesn't have a PC socket then you can normally buy an adapter which slides onto the flashes Hot Shoe to provide either a PC cable or socket to allow other devices to be connected to the flash.
Price	You could choose to buy 4 second hand Nikon SB-28's or 1 new Canon 580EXII for about the same price. Their power output is virtually identical. It really comes down to what you want and how you work. The best option might be the most expensive one if it works best for you.


If a single strobe is not powerful enough then 2 or more can be used to increase light output. You will need to double the number of strobes for every extra stop required. For example, a second strobe (2 in total) will give you one extra stop of light. To achieve one further stop of light you need to double the 2 existing strobes and have 4 strobes in total. If working at night then you can simply pop a single strobe as many times as needed.		These softboxes are fitted to simple battery powered strobes with custom made brackets so are compact and fast to use. Unfortunately most small strobes loose too much power to be very useful with such light modifiers so this is where larger and more powerful strobes have an advantage, especially if large light modifiers are to be used.

Triggers, radio, optical, cables, or, there's more than one way to synch a strobe

Off camera flashes all need to fire at the same time and the way this is done is either by connecting them to the camera with synch cables, using light activated Slave Syncs (triggered by another flash), using radio transceivers such as PocketWizards or a combination of the above.

Synch cables are a problematic because people can trip over them, they are unreliable, they are always too short and take time to pack and unpack properly. Keep away from them if at all possible.

Almost all studio or high end strobes have optical slaves built into them as they are an ideal method of synching strobes in an enclosed environment, such as a studio. Light activated slaves can be problematic in bright sun or some times over a long distance, even with the better quality units, but you do generally get what you pay for so the performance of slaves can vary significantly. Although this method is the cheapest, as all you need are cheap manual flashes and quite cheap slaves, the disadvantage is that you will often be limited to line of sight applications as each flashes slave must be able to see at least one other flash so that it is activated. Optical slave syncs are very handy to have but not as a primary method of triggering flashes other than in a closed environment such as a studio. Optical slaves are ideal for supplementing radio triggers as not everyone can afford to have a radio trigger for each strobe.

PocketWizards, or similar high quality radio slaves, are probably the most important investment you can make next to the actual strobe itself. Radio slaves have always proven to be far more reliable and quicker to set up and use than optical slaves except possibly indoors or where the ambient light is very low and unlikely to affect the optical slaves. Radio slaves are not without their problems and can at times fail to work altogether due to external or ambient radio interference beyond your control but this is not a common problem.


Optical slaves are very handy and cheap so it's a good idea to have a few as spares or for any extra flashes that only get used occasionally. Good quality slaves can often be used in full sun if care is given to their placement, ie preferably not pointing directly towards the sun itself.		Radio slaves are the most practical and reliable means to synch multiple flashes.

Hand held flash used to fill a dark engine bay. Note also the sophisticated camera to flash synchronization system being being used here. It's a proprietary system called 'Shaun'. That's right, when Shaun hears the shutter open on the camera he presses the 'lightning bolt' button on the flash and it makes light! It works quite well in a pinch and when the exposures are long enough for Shaun to press the button in time. A light stand and radio synchs would have worked just as well but would have taken much longer to setup. Some times the simplest method is best.

Flash light output compared, or, how to compare apples and oranges

A flashes power can be described in a number of ways and these different methods can be difficult to compare. Small flashes are often described using a Guide Number however the methods used to determine these numbers are not always the same so direct comparisons can not be made unless the factors used to calculate the Guide Number is clearly defined. The power capacity of larger strobes, such as monolights, are usually described in Watt/Seconds (W/S) which is a description of the electrical power storage capacity of the flash rather than a direct measure of the light output of the unit. The two are directly proportional, ie the higher the W/S the more powerful the strobe and the brighter the light it creates but a 500 W/S unit from one company may or may not have the same light output as another 500 W/S flash from another brand due to differences in the efficiency of the electronic components and designs.

The Guide Number of a flash is often stated by a manufacturer so this information can be standardised to some degree for comparison purposes and this method is used in the table below. If the Guide Number is not know then it can be calculated from an incident flash meter reading. It is still important to describe the reflector or flash zoom setting used as this will affect the intensity or concentration of the flashes light, as can be seen in the table. As many flashes where historically designed to have the same coverage as a 35mm lens this will be the basis of the measurements below, and in the case of monolights, they will be tested with their standard or normal reflector. The table below shows the test results from several flashes as well as many flashes which have NOT been tested but are listed simply as a guide and for comparison purposes (see Note #3 below). Where F stops are quoted a distance of 3 metres (3m or 10 feet) is used as the basis for all comparisons.

Flash	Reflector setting in mm and/or horizontal angle in degrees	Manufacturers stated Guide Number in metres (See note #3)	Aperture at 3 metres or 10 feet based on manufacturers stated Guide Number (See note #3)	Measured/tested aperture reading at 3 metres or 10 feet (See note #1)	Measured/tested Guide Number in metres (See note #2)	Watts/seconds
Nikon SB-28	35mm	36	F12	F8.28	25
Nikon SB-28	85mm	50	F16.6	F11	33
Nikon SB-900	35mm	34	F11.3
Nikon SB-910	35mm	34	F11.3
Canon 580EXII	35mm	36	F12	F7.21	21
Canon 580EXII	105mm	58	F19.3	F10.93	33
Canon 600EX and 600EX-RT	35mm	36	F12
Canon 600EX and 600EX-RT	105mm	58	F19.3
YONGNUO EX600 FLASH	105mm	58	F19.3
YONGNUO TTL Speedlite YN-565EX	105mm	58	F19.3
Sunpak Auto 511	35mm	30	F10
Sunpak Auto 411	35mm	30	F10
Sunpak Auto 522	35mm	36	F12
Sunpak auto zoom 3600 Thyristor	35mm	36	F12
Sunpak Auto zoom 4000	75 degrees, approx 28mm	40	F13.3
Sunpak Auto zoom 3000	approx 35mm	?	?	F6.5	19	115 ws
Sunpak Auto Pro 120J TTL	Standard, 45 degrees	45	F15			115 ws
Sunpak Auto Pro 120J TTL	Wide Angle, 63 degrees	36	F12
Sunpak auto 544	35mm	42	F14
Sunpak auto 555 or G4500DX	35mm	45	F15
Sunpak auto 611	35mm	48	F16
Sunpak 622 Super Pro-System	35mm	60	F20
Sunpak auto 622 pro-system	35mm	50	F16.6
Metz 60 CT4	28mm (62 degrees)	60	F20	F13.45	40	300 (approx)
Elinchrom Ranger Quadra AS	RQ 13.5cm Refl., 70 degrees, Quadra S Head	38	F12.6			400 ws
Elinchrom Ranger Quadra AS	RQ 18cm Refl., 55 degrees, Quadra S Head	52	F17.3			400 ws
Elinchrom Ranger RX	Standard, 48 degree	128	F42.7			1100 ws

Notes:
#1 Measured with Sekonic L-358 incident flash meter, at ISO 100, at 1/125th second exposure, average of at least 2 test readings
#2 Fractional aperture values used in the calculations where sourced from How fast is F1.2, or, fractional F-Stops compared
#3 Where ever possible, data has been sourced from manufacturers own web sites or manuals and in some cases has been converted or calculated to allow comparison (at ISO100 and at a distance of 3m). No warranty is given about the accuracy of the data or calculations. Always refer to the manufacturers web site for accurate and up to date information about their products.

Summary

Everyone's needs and preferences will vary so choose a lighting system that works for you. Hire equipment to try it out instead of buying and finding it doesn't quite do what you want. The best and most expensive gear won't necessarily be the best for you.

Definition of terms

Term	Definition
Flash	The meaning of the term 'flash' has changed over time and now refers to any form of electronic flash, regardless of the design or style of the equipment itself. It is the most generic term describing modern electronic flash equipment. Historically the term referred to powder or flash bulbs which had the exact same purpose as modern electronic flash, ie to provide light for a photograph, albeit via different mechanisms.
Strobe	'Strobe' is short for 'Stroboscope' which is an electronic flash designed to pulse continuously at regular intervals, as opposed to a typical photographic flash which only fires once each time it is triggered. Like many words it's meaning will depend on the context or application and if you asked an engineer or a scientist they would probably understand a 'strobe' to be a 'stroboscope'. However in photographic applications the term 'strobe' came into use in the 1940's and referred to any electronic flash used for photographic purposes, ie an electronic flash. Today, and in the context of photography, the term 'strobe' may imply a large professional electronic flash such as those you might find in a studio, but there is no justification for this. 'Strobe' is simply another name for a 'flash'.
Speedlight	The term 'speedlight' originated in the 1940's and is a generic term referring to any electronic flash. In common usage it still refers to any electronic flash however its use by manufacturers such as Nikon for small, compact hot shoe mounted flashes has implied a meaning of small/compact hot shoe mounted flash. Arguably the term still refers to any electronic flash however common usage may lean towards small/compact shoe mounted flashes.
Speedlite	The term 'speedlite' is a trade or brand name used by various manufacturers such as Canon and Ricoh.
Monolight	A self contained electronic flash typically used on a light stand and in studio environments. They are typically mains powered, have a built in modelling light and are much more powerful than hot shoe mounted flashes. Monolights are distinguished from a 'power pack' based strobe which contains the bulk of the electronics and flash controls in the power or floor pack and with lighter/smaller and often special purpose heads attached to the power pack with specially designed cables.
Monobloc	Same as 'Monolight'.
Strobist	Strobist is a registered trademark owned by David Hobby and is not a generic term however it is frequently used online as if it where. It's common to see the term 'strobist' used online, usually by people new to photography, to mean 'flash photography' itself or to refer to a type or style of photography, ie flash photography using small strobes.
Inverter	An electronic device which converts a low DC (direct current) voltage, eg 12/24 volts, to a higher AC (alternating current) voltage such as 110/240v. There are many makes and models of inverters but few are suitable for use with flash equipment. A couple of the most commonly used inverters are the Innovatronix Tronix Explorer range or the Paul C. Buff Vagabond Vagabond/Mini range.
Guide Number	A Guide Number, or GN, describes the power of a flash in a way that also allows you to calculate the required exposure. The Guide Number is calculated simply by multiplying the aperture and distance. The ISO and measuring system used must also be described, ie metric or imperial. Other factors affecting the light output of the flash must be defined, such as the zoom setting or reflector that was used. If you know the Guide Number for your flash then you can calculate the exposure by dividing the distance into the guide number. For example a Metz 60 has a guide number of 60 (in metres and at ISO100) so the correct exposure for a subject 3 metres away should theoretically be 60/3=20, or F20. As can be seen in the table above the measured exposure (averaged over 5 different Metz 60 CT4 flashes) is approx F11.5 so the measured Guide Number based on the above tests would in be 40. In this case the measured guide number is considerably different to that stated by the manufacturer and it can be difficult to know the reasons for any discrepancies but some of the many factors could include age and condition of equipment, the accuracy of meters used and the environment or room where the tests are conducted etc.

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