THE BEGINNER'S GUIDE TO FLASH
Flash photography can be an absolute minefield for beginners to navigate. With so many different strobes, triggers and accessories out there, it's hardly surprising that the newcomer's mind boggles and indeed, many feel put off and intimidated. They hear more experienced photographers speaking of technical jargon and terminology: Manual, TTL, Optical Slave, Sync Speed, Guide Number, T=0.5, T=0.1, Off camera, and so on.
Quite simply it's information overload and overwhelming. Hopefully by reading this guide you'll have a better understanding of the terminology and the mechanics behind it all.
To make things simpler, we can organize flashes into 3 groups. Before we do that though, it would be remiss of me if I didn't point out that the terms "speedlite, strobe, flash, flashgun" are all interchangeable for one another and refer to the small flashes we place on our camera hot shoe. Studio flashes are generally referred to as strobes or monolights and are mains powered or using a large external battery pack. Okay with that done, lets look at flashes.
First up are TTL Flashes (Nikon=i-TTL, Canon - e-TTL, Pentax p-TTL). TTL stands for Through The Lens and it's a way of metering (measuring) the amount of light from the flash. In essence it works like this. The flash fires a "preflash(es)" which hits the subject. It then reflects off of them and enters the camera via the lens and is measured. The camera determines how much power is required from the flash and communicates this information to it. The flash then fires moments later, just after the shutter opens to reveal the sensor. Where this happens so fast we cannot distinguish between the pre flash and the actual flash that is recorded by the sensor. We just witness a single pulse of light. If done correctly, our subject should be correctly exposed. It's perhaps the easiest type of flash for newcomers as there is very little to calculate on their part, as the camera and flash do most of the work.
Next are Manual Flashes. These look identical to TTL flashes but lack the ability to adjust their power automatically. The user has to input the power output by hand which can be adjusted from full power 1/1 down to 1/256 power. Not all flashes have this range and may bottom out at 1/64 or 1/128. Manual flash is a lot harder for beginners to work with and have to guess exposure, review the resulting image on the LCD screen and then make adjustments based up that. This is known as "chimping". Its effectiveness can vary depending on whether your LCD screens brightness is a close representation of the actual exposure and you may need to adjust the brightness in the camera settings. An alternative and far more accurate way is to use an external light meter.
Monolights. These are large manual flashes that are commonly used in studios. They are mains powered (although some can be fed via hugely expensive battery packs). They have the advantage of modeling lamps, which is essentially a bulb that enables you to see where the light and shadows are falling. A very handy feature to have, I can assure you. Monolights can be analog or digital in terms of their interface. I prefer digital as you can alter the power in small incremental steps for extremely accurate exposures. Another benefit to the monolights is the array of modifiers available for them, which fit directly to the unit itself. Many can be used on speedlites too with adapters, as I do myself.
TTL VS MANUAL FLASH
On the face of it, TTL flash is the better technology. It takes virtually all the thinking out of the equation. It's just point and shoot. So you may wonder why doesn't everyone use it? The answer is control. While TTL does a pretty good job in most cases, it's not infallible. The meter can get tricked and your exposures look awful. Where you have the time to position your subject and really fine tune the lights, manual strobes - particularly monolights offer the greatest accuracy, with many adjustable in 1/10th stop increments.
If you are aiming to become a studio portrait photographer, then monolights offer the greatest degree of control in terms of exposure, shaping and finessing of the light. The modeling lamps save a lot of time when it comes to positioning and angling of the light. It's much better being able to do this in real times, rather than continuously walking back to your strobe, making a blind adjustment and returning to the camera to take a photograph, to see what those changes have done. That's not to say that you can't use TTL flashes for posed portraiture. You can and they do work very well.
On the other end of the spectrum, if you're looking to become an event or news photographer, you simply don't have time to make repeated exposure adjustments. A TTL based flash system is much better suited to your needs. Price can also be a prohibitive factor. Manual flashes start from under £50 with very popular models like the Yongnuo 560 II and the Mk III version with its inbuilt radio triggers for just a few pounds more. For the top of the line Nikon or Canon flashes you are looking at around the £350+ mark and lesser models in between. So as you can see, there isn't a once size fits all. It's what suits your photography and what you finds works best for you.
USING MANUAL FLASH
Manual flash can be extremely difficult to get your head around, unless you are naturally observant, technically minded, with a propensity for problem solving. The main issue is getting correct exposure. Two things affect this (independently of the camera).
Firstly is the amount of power the flash is outputting. Most people would quickly spot that one. The second isn't so apparent, which is the distance to subject. For example, you could have your flash on a stand positioned 1 meter from your subject at full power. The resulting photo is grossly over exposed. However, if you were to move your stand 2 meters away, leaving the flash at full power, the exposure may be correct.
This is because light falls off over a distance and is known in photography as The Inverse Square Law. If you're going to work with manual flash, then understanding the basic concepts will greatly facilitate accurate exposure and professional looking results from the placement and spread of light. You don't need to know all the scientific formula just the following :
The closer your light to the subject, the brighter it will be
The further you light to the subject, the dimmer it will be
The closer your light to the subject, the quicker the light falls into shadow
The further your light to the subject, the more evenly the light will spread
The Inverse Square Law. Note that the distance when multiplied by itself will give the fraction of the light power.
You can witness this effect yourself by shining a flashlight on a wall in the dark. From a distance of a few meters the circle of light is quite large, with not a huge difference in brightness from the center to the edge. Move the flashlight very close to the wall and the light becomes much brighter and concentrated, with the contrast between the center and the outer edges noticeably higher.
From the above diagram you can see how wildly exposure can very, especially at close distances. Moving the light from 1m to 2m in distance cuts the flash power by 75%! If you are lighting a group with off axis light, it is better to get the source further away as the gradation is much less severe.
When using flash it's important to give yourself somewhere to go in terms of power and aperture. If you're using something like an f/1.8 lens, start your aperture at f/4. This gives you the ability to go 2 1/3 stops wider to adjust exposure. Its also a good idea to start your flash on half power, so again you have the ability to make alterations.
If your subject is too dark, you either need to open your aperture or increase flash power. You could of course up your ISO too, as well as having the option to move your strobe closer to the subject. If you do the latter, just be aware that you are affecting the spread of light on their face which might not always be desirable. If you want a specific aperture, then you will have to resort to flash power, ISO and placement of the light source to get that specific value.
This is the maximum shutter speed you can use with your flash. If you go above it, you will end up getting a black bar across the bottom of your image from the rear shutter curtain. Depending on your camera, the sync speed generally ranges from 1/160 sec to 1/320 sec. There are "tricks" to get around the sync speed like High Speed Sync but, it's no substitute for proper sync speed. The reason being is that you control the exposure of ambient light with the shutter speed, just as you do in a non flash photo.
However shutter speed does not control flash due to the fact that it fires considerably faster that the shutter does. On low power settings it's not uncommon to achieve a pulse of light equivalent to 1/20'000 of a second. That's 100 x faster than your average shutter sync and some serious freeze action stopping! Aperture controls the flash, since you are physically reducing the size of the gap the light passes through to reach the sensor. Of course ISO does too by making the sensor more sensitive to light.
MIXING AMBIENT AND FLASH
With the above in mind, we can see how its possible to mix and vary the ratios of ambient and flash light in a photo. Say for a moment we were photographing a model outside in a field. Back lit by the evening sunset. We choose a shutter speed of 1/60 sec and aperture of f/8 on our kit lens to sharpen the image and provide a deep enough depth of field to ensure she's in focus front to back.
We place our flash off camera on a stand, which is wirelessly triggered. We adjust the power of the flash until we get f/8 worth of light on our subject. We can do this by chimping - taking a photo, see what the exposure is like and adjusting as necessary, or simply by using a light meter, which saves a lot of time, messing about and extremely accurate (provided your meter is profiled to your camera).
We take a picture and look at it on the LCD. The model is correctly exposed by the sky is a bit too bright. By increasing the shutter speed from 1/60 to 1/125 we reduce the exposure of the sky by 1 stop of light. If its still too bright we can increase to 1/250 sec to reduce the brightness by yet another stop. The model says exactly the same, as only the flash is lighting them. Conversely if it was too dark, we could open the shutter to 1/30 or below, which depending on your focal length is probably best taken on a tripod.
This is why having a camera with a higher sync speeds is more beneficial as it gives you greater control over the ambient light. Remember shutter controls ambient light. Aperture controls ambient and flash. ISO controls both too.
GETTING MORE FROM YOUR BATTERIES
With that in mind we can actually get more life out of our batteries by way of the ISO. Most modern DSLRs are capable of producing very clean images up to 800 ISO. Full frame cameras easily 1600 ISO. If the native ISO of your camera is 200, by shooting at ISO 800 you can effectively get 4 times the number of because you can use the flash at two stops lower power because you increase the ISO by two stops. If you're out shooting all day, this is a great way to get more shots from your flash. It also means you get faster flash duration times and recharge times, due to using the strobe on a lower power!
There are more light modifiers and flash gadgets than you can shake a stick at. Some are highly effective. Others are more gimmicky and offer no real benefits over conventional modifiers - just people trying to reinvent the wheel and make some money into the bargain. So where to start?
Well as the name suggests, modifiers are about manipulating light. This is done by altering the spread, specularity and contrast to create very different looking images.
At the smallest end of the scale we have grids. These are simply a honeycomb mesh that is placed over the front of the flash. They act to reduce the spill of the light by preventing it from spilling out. It can only travel in the linear direction afforded by the grid holes.
The result is a concentrated area of light. Grids are often employed in low key, high contrast images where we may want to illuminate just a small area on a subject.
Snoots perform a similar function. Either a metal or fabric cylinder that channels the light into a more linear spread. For ease of transportation and storage, I like these little grids from Micnova, which are available in both 1/4" and 1/8" honeycomb size.
Next up are flash diffusers, like those made by Sto-fen. These slip over the head of the flash and make the spread more omni directional. They also serve to decrease the specularity of the light, making it less crisp. Great for photography when employing bounce flash. Some of the light is thrown forward to act as fill.
Generic version are widely available for virtually all flash models. Coloured versions for warming, cooling and fluorescent lighting can be had too. If buying for a Yongnuo YN-560II flash, the models for the Canon EX580 will fit.
Above the Omni-Bounce flash diffusers are small softboxes like the Lastolite Speedlite Ezybox. A robust little 22cm softbox that fits easily and securely over our flash. It increases the size of your light source quite significantly, thereby producing softer shadows than the bare flash itself. There are two layers of diffusion inside to help distribute the light inside.
For simple storage and transportation, the Ezybox collapses down into its own pouch. Again, this modifier is ideal for event photography where moving large equipment on the fly is not an option. There are also 38cm and 76cm versions available but these need to be used off camera due to their size.
A Micnova 1/4" grid. Also available in 1/8"
Sto-Fen Omni Bounce
Lastolite 22cm Ezybox for speedlites.
Beyond this you are into the realms of off camera flash modifiers, including umbrellas, beauty dishes, softboxes and octabanks, which come in various sizes. The larger the modifier, the softer the shadows and less contrasted the light is. The smaller the modifier, the harder the shadows and more contrasted the light. We use both for different looks and effects. Light your model from the front with a large beauty dish or softbox for flattering, wrapped lighting and hit them from behind with a small light source to rim light them.
For maximum creativity with light, its imperitive that you get the flash off the camera. If all we ever used was a speedlite attached to the hotshoe, our photographs would be pretty boring in this respect. By placing a flash on a light stand we can control the direction and the angle that light is coming from. We can also use multiple light sources for really dramatic looks.
The placement of your flash is paramount to getting good lighting on your subject. Direct flash (coming at the subject from the same angle as the camera) will result in "flat" lighting. There will be little in the way of shadows since the light is able to hit their face evenly. Shadows are what create depth in an image so don't be afraid of them. The shadows we generally want to avoid are those ugly ones cast by the midday Sun, where the eyes are barely visible due to shadows caused by the eyebrows.
Experiment with different light positions to create different looks and feels. Move the flash at 45 degree increments and take a photo to see what the effect on the subject is. Remember, light should reflect the scene. It creates the ambiance in a photograph, so if you're photo is meant to be fun, energetic and lighthearted, your lighting should mimic this. If you're trying to create something dramatic, nefarious or menacing with a photo, aim to do so with your lighting too. Generally low-key, high contrast works better with the latter as you can play with light and shadow to invoke more drama. Also, unless you're doing a horror scene, avoid having your main light source coming from lower than the head. This causes shadows from the nose to be cast up the face and looks unnatural.
RADIO TRIGGERS & OPTICAL SLAVES
In order to fire our OFC (off camera flash - yes its good for you to learn all these abbreviations) we need one of 3 things. First is a sync extension cord. This is simply just a cable that attaches to the camera hot shoe and the bottom of your flash. The only time I'd recommend one of these is for macro photography, where you have the flash on a bracket attached to the camera and need to connect the two. I'd avoid them for all other OFC photos. The reason being is that they limit your working distance, due to the fact that the cable is tethering you to the flash on a stand. Also, they are potentially dangerous, both as a trip hazard and toppling your light stand, if its not heavily weighted down. On top of that, they are just plain annoying, draping off the top of the camera.
Second is optical slaves. Virtually all flashes have these, even the Yongnuo 560 II and some studio strobes too. If your Nikon camera has CLS (Creative Lighting System) featured, you can use the pop up flash as commander unit. It then sends a pre-flash signal to your remote flashes. These in turn see this pulse of light and fire themselves. Its a very cost effective way of doing things, as you don't require any additional equipment. However, its not without its limitations - hey its cheap there's bound to be some!
The problem is that you need a line of sight. Your slaves need to see the commander flash. If your speedlite is inside a large softbox then its possible that the optical slave will not detect your commander pre-flash and subsequently not fire. It also means that you cannot places strobes in other locations. For example, say you wanted to shoot a model entering a doorway from a darkened room, where the room to be entered would serve as the light source. Without being able to see the commander pre-flash, this creative use of light would not be possible.
This is where radio triggers come in. One attaches to the camera hot shoe, the others to your flashes. Now line of sight isn't a problem and allows for maximum artistic potential. There are many out there on the market. Some cheap and not so cheerful, to industry standards like Pocketwizards. Not all operate on the same frequency. Some are on 2.4Ghz. Pocketwizards are 344Mhz in the US and 433Mhz in Europe. If you're planning on using a Sekonic meter like the L-758DR which can trigger the Pocketwizards to take a reading, make sure you get triggers on either of those frequencies, not 2.4ghz ones! In the UK the Interfit Strobies Titan Pro STR158 triggers operate on the 433Mhz frequency and are cheaper than the pocket wizards.
Hopefully this article gives you some knowledge and confidence to wade into the waters of flash photography. TTL systems are great - I have a Metz 58-AF1 myself, which I occasionally crack out for parties and such. For everything else, I'm a manual flash fan. For anyone starting out, I'd recommend learning manual flashes as it gives you a much better understanding of the mechanics, because you're forced to control all the variables yourself.
Flash lighting provides incredible lighting opportunities for looks we wouldn't able to achieve otherwise, as well as action stopping abilities. If you take the time to educate yourself on the inverse square law, hard and soft light sources and how to manipulate light to your advantage, you will be rewarded with fantastic photographs too.
For starting out, I highly recommend the Yongnuo YN 560 II or III flashes. The latter is just an updated version with inbuilt triggers, although they are 2.4Ghz, not 433Mhz. Great value for money. I have 6 of them, half of which live permanently in the studio. Use the links below to get yours through Amazon!
For studio use, I'd suggest the Paul C Buff Einstein if you're in the US and the Lencarta SF300 in the UK, which is great value. The Einstein is available in the UK too but at £600 its pretty pricey, although thoroughly excellent. The modeling lamps make life so much easier. Just take your time with flash. If your exposures are off, it's something you are doing wrong, so don't lose your temper with the equipment. After a while it will all become very fluent and second nature and you'll really love the art of flash photography.