Flash Photography

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    Flash Photography
    Flash Photography

    Small flashes are composed of three components.

    1. Battery
    2. Zenon Flash Tube
    3. Circuitry to raise voltage from battery

    Once batteries are inserted, the circuitry raises the voltage from hundreds to thousands of volts by holding the power in capactiors.  This energy is then discharged whenever used, and the process starts again.

    This raising of energy can take some time, so be patient.

    The ability for the flash module to produce light almost in comparison to the sun, from such a small package is amazing.  It also occurs in thousands of a second, which is important.  If you wanted to reproduce the amount of light in a constant shine, would would need entire trucks full of batteries to power the bulb.

    Flash can freeze action better than fast shutter speeds.  In fact, the cool high-speed action photography that people love is achieved using high-speed flash, not super fast shutter speeds.

    The Qualities of Light

    It’s important to know that not all light i equal.  Light has 4 qualities to be aware of and control.  They are:

    • Intensity
    • Color
    • Direction
    • Texture

    Intensity

    This is a measure of how much light is hitting our subject and reflecting back to the camera.  We can control this with

    Turning up or down power on flash module.  We can also move subject closer or futher away from light source.  Light follows the inverse square law, which really just describes how two related components change in relation to eachother.

    If you have a pleasant amount of light on a subject from 1 meter, then move the light source to 2 meters, you would have to increase the amount of light by a factor of 2.  Light drops off very fast and a subject 8 feet from the light is much, much darker than a subject 2 feet from the light.

    This is because as you move from 2 feet to 4 feet, you would need 4 times the light.  From 4 ft to 8 ft, you would need 16 times the light, which is a tremendous increase!

    This is why its important to get flashes as close to the subject as we can!

    The Color of Light

    Our eyes and brain do a great job of balancing different light colors, but the camera sensor cannot do this very well.  Light is described by it’s temperature, with warm white being yellow and cool light being blue.

    The Direction of Light

    The direction of light as it hits our subject can have a huge effect on the composition and the message the photo conveys.  45 degrees to the side and 45 degrees up is standard portrait light position.  Moving the light to 60 diegrees to the side gives us Rembrandt lighting, as typified by the triangle of light on the fill side of the subject.  This is more dramatic and regal.

    At 90 degrees, we get split lighting.  This adds event more drama.  Taken a bit further, position your subject to look 90 degrees from the camera and position the light about 10 digrees further to achieve profile lighting.  Super fun and dramatic!

    Texture of Light

    Described as hard or soft light, or direct or diffuse light.  It can be conceptualized in a few different ways:

    Hard light creates hard shadows while soft light creates soft, diffuse shadows.

    Direct light comes from a small light source, while soft light comes from a relatively large light source.

    Think of the transition from shadow into light.  If there is a gradient, then you are using soft light and a diffuse light source.  The gradient is known as the penumbra, and diffuse light creates a soft, gradual penumbra where the light falls more intensely on the background as you move further away from the subject.

    As you move the light further from the source, you decrease it’s relative size, thus making the light more direct and harder.  As the light moves towards the subject, it becomes softer and more diffuse.

    Exposure Triangle

    Understanding to control exposure without flash is the fist step to getting good results from flash.  Exposure is how much light is hitting the sensor, and we have three settings to control exposure, all which move relatively with one another:

    • Shutter Speed
    • Aperture
    • ISO

    Shutter Speed

    Meausues how long sutter is open and camera sensor is exposed to light.  Expressed as a fraction of a second.  The longer the shutter is open, the more light gets in, and the brighter the image is

    Aperture

    These are blades the move in front of the sensor and constrict the amount of light that can reach the sensor.  In new, digital SLR’s, the camera tells the lens to engange the aperture whenever a photo is taken, so you only see the bladed move in from of the sensor at the point of taking the photo.

    It is expressed as an F-number. F numbers represents the relationship between the size of the aperture and the focal length being used.  Small F number means larger aperture, while large F number means smaller aperture.

    Smaller F number lets more light in, so you get brigher image.  Larger F number means less light to sensor, so darker image is result.

    ISO

    Originally, some film was more sensitive than other film, so ISO referred to how sensative the film was when exposed to light.  For digital photography, ISO simply reppresents the senstitivity of the sensor, which we can increase or reduce manually.

    This represents one of the biggest advances in digital photography.

    ISO is exporessed as numbers, with higher numbers being more sensitive.

    Here’s how it works: When taking a photo, digital sensor converts the light that comes through the lens to data.  When you increase the ISO, you are increasing the sensitivity of the sensor, so if less light were to hit the sensor, the data values would be increased to compensate.

    Set your camera light meter to spot meter, then use the persons face as the subject for the spot light meter.

    You are able to achieve and acceptable exposure from thousands of different combinations of the settings, a configuration known as the exposure triangle.  The settings not only affect the amount of light, but they change some of the properties of your photography.

    Shutter speed affects the amount of motion blur.  Slow speed allows more blur, while fast freezes the action.  We must always use a shutter speed fast enough to control for camera shake.  The general rule is to keep shutter speed faster than 1 / focal length of lense.  So, if shooting with 85mm lens, can’t handheld slower than 1/85th.

    Aperture affect the depth of field.  It refers to how much of the scene is in focus.  If we want to pull subject from background, use a larger aperture to blur background.

    ISO introduces film grain into the image.  Always use the lowest ISO possible to achieve the image you are looking for!

    Small Camera Flash

    The built in camera flash is known as the pop up flash.  You never want to use this flash if you have access to a speedlight.  If you have to, it can be used to fill in light when you feel the light source isn’t adequate.

    Many times, this fill light looks cheap and overpowering.  However, using the flash compensation to drop the intensity a bit has amazing effect on the exposure.  It is useful to brighten up shadows.

    Pop up flash also give a nice light to the eyes.

    Pop up flash isn’t desirable because it is small and hard.  It is also close to the lens, resulting in red eye.  It’s also not possible to fully control, so try to use speedlight.

    If you have to make your pop-up flash work for you, you can diffuse the pop up flash by placing diffusion material in front of pop-up flash.  You can also try taping a piece of parchment paper to the flash, but you’ll look ridiculous.

    You can also bounce the pop-up light to the ceiling to give a more pleasing light source, with a white business card or anything reflective.  It will look absurd.

    Flash Speedlight

    When using your speedlight, you can set the flash module to TTL mode.  TTL is basically an auto mode, the camera and the flash work together to create the best exposure.  It might not always be what you want, but it is fast and allows you to avoid mistakes.

    TTL is best used when the subject changes distance quickly, like shooting a couple dancing during a wedding.  Stay in manual mode for the rest of the time.

    Flash Sync Speed

    Most DSLR’s have a maximum shutter speed of 1/200th to 1/300th of a second.  If your shutter speed is faster than your max sync speed, you’ll get dark bars in your image.  Some cameras will prevent you from setting a shutter speed faster than the max sync speed.

    High end flashes have HSS, or High Speed Sync, which allows you to use faster shutter speeds, but the intensity is reduced, so you have to be close to your subject.

    How to balance ambient light with your flash

    Ambient light is the natural light in your scene.  It is the light you don’t have much control over, most likely the sun.  When shooting at night, ambient comes from the moon, streetlights, cars, etc.  When inside, ambient light comes from overhead lights and lamps, and windows.

    It is often difficult to expose for both the subject and the background perfectly when composing your shot.  Take an example of a house, if you point the lens toward the window, you will have to choose between properly exposing for the outside or exposing for the interior.  Either way, one component wont be ideal.  There is a third option, however…

    Flash photography allows you to balance the ambient light in the scene.  First, identify what you can and can’t control.  If you can’t control the the background light, expose for the background in camera.  Then turn your flash on and begin at 1/16 of the full power.  If not ideal, you can increase the power of your flash until you get the proper exposure for both the background and foreground (plus the subject!)

    Bouncing Flash

    Bouncing flash is fastest way to improve flash photography.  Instead of pointing flash at subject, point at object to reflect light onto subjcect.  This light is more diffuse than light directly from the flash head.  The only real downside of bouncing your flash is that it requires more power, so your batteries will wear down faster.

    Bounce flash is great when inside.  Look around the walls and ceilings and notice where they are in relation to the subject.  This determines how much power you will need for the flash to reach the subject.  Go for closer surfaces than further.

    Also look at the the color of the surface.  If you bounce your light off a colored surface, the light will take on that color when showing over subject.  If surface is dark, then it will take more power to bounce light off of them.  If you are too close to subject, you can use the white bounce card with the light pointed up lighten the eyes and create a catchlight, or sparkle in the eye.

    You can really bounce you flash of anything .  It is a skill that must be learned and practiced to master, as it offers a ton of possibilities.

    Off Camera Flash

    Off camera flash allows you to truly paint with light, as you can create your own light source.  This gives you an entire world of different possiblities, lets explore!

    Lets get some vocab out of the way:

    Master – Offers instructions

    Slave – Performs Insturctions

    Trigger – Transmits instructions from one device to another

    You can have a master or slave flash, you can have master or slave triggers, and you can toggle master or slave mode, respectively.

    The process goes like this:

    When you press shutter, there is 1/10 of second lag between plunger press and shutter opening.  During this time, the hot shoe receives signal to flash and sends it to trigger.  If using wireless trigger, radio waves are sent from master device to slave device, which then triggers remote flash.

    THere are many different ways to send signal to remote connection.  use a dumb snyc cord from camera to rmote flash to trigger flashing.  If using TTL sync cord, can send hot shoe information, and maintain TTl functionality.  TTL cable is better, but costs more, so get what you can.  Tethered also has problems

    Optical slave systems have a sensor that looks for light, so whenever another flash goes off, they fire off adding light to scene.  Because of simpliticy, it is inexpensive.  You get a range uf up to 40 ft with the flash.  But must have line of sight between flash units.

    You can also use proprietary wireless systems.  These use special flashes the fire before the shutter, sending info tot he remote slave device.  The device sinks up and sends data back, then the remote device fires at the moment of sensor expposure.  This is more expensive.

    Radio trigger ssytems are the best.

    Put your flash on a light stand, but choose the right one for the right situation.  Is it light or heavy.  How tall iis it.  You want to shoot for alteast 7 ft, to caputre standing adults.

    Flash Modifiers

    DOn’t forget about speedlight modifiers.  There are 4 qualities of light, so a flash modifier is anything we use to affect one of these qualities.  Using manual flash gives you control of instensity.  Off camera flash gives you control of intensity.

    When photo of scene with different color light sources, you won’t like thr results.  You need to change one of the light sources, and it is usually easist to change your flsh, so you can use CT gel to change the color the light being emitted.  CT stands for color temperature.

    When affecting the texture, there are many ways to soften or diffuse the light.  Of course, bouncing is the first optipon.  A 43inch shoot through umbrella is versatile.  This bounces light all over the room and can loose directionality, so you can also use a softbox.

    Lastly, there is a beauty dish.  This directs the light into a parabolic surface and spreds it around, not diffuses it.

    A snoot is different in that it doesn’t soften our lite, it just makes it hyper directional.  Flags are the same, but it only blocks light on one side.

    Combining Slow Shutter Speed and Flash for Awesome Effect

    Its a photography axiom that you need to use fast shuter speed to get sharp photo with no motion blur.  Flash photography gives us more possibilities in that the fast action of the flash allows us to freeze motion with a slower shutter speed (all the way down to 1/30th!)

    First, you have to watch for motion blur from camera shake.  If whole scene us blurry consistently, this means you had camera shake and you need to steady yourself or use a tripod.

    First Curtain Flash Sync

    This is the default mode for most camera and flashses.  When you take a photo with a set shutter speed of, say, 3 seconds, the camera and flash work together to fire the flash as soon as the camera opens the shutter.  The flash shines for about 1/10,000th of a second, after which the shutter sits open for the rest of the duration, collecting ambient light, before closing.

    Second Curtain of Slow Sync Flash

    Second curtain sync is the opposite, the camera would work with the flash to open the shutter first for almost the enitre duration of the shutter interval, then the flash would first in the final 1/10,000th of a second.

    Three ways to use slow shutter.  First, with camera on tripod and fairly still subject.  Set the settings to capture the ambient light the way we want, and flash to illuminate the subject.

    Keep camera on tripod, but subject is moving and ambient light is hitting the subject.    First curtain sync results in the blur that leads away from subject because the flash fires at beginning, then dies off.  Slow sync reverses this, make the motion blur lead into the subject with great clarity and a very cool look!

    To really bring a viewer into the scene, use a moving subject and handheld for a vibrant, authentic effect!

    Stroboscopic Flash

    Using a longer shutter speed, you will fire the flash many times during the shutter opening.  First, compose the scene, then find a very dark background with little ambient light.  Set your flash to Multi or RPT (may differ by flash manufacturer) and choose your flash interval as expressed as Hertz.

    You are also able to set the flash to stay on for as long as the unit allows, within the duration of the shuter sped, for some very intense effect!

    Fill Light and Bouncing

    Fill light is best understood opposed to key light.  Key light is the main light in the scene, generally the brighest light illuminating the subject.  Every composition has well-defined key light, excluding silhouete.

    Usually the most important light, this is the first one you set up and dial in the way you want.

    Fill light, on the other hand, is used to reduce the contrast created on the subject by the key light.  Many times, the key light will create unpleasant shadows that then need to be filled in by a 90 degree offset light, or fill light.

    Key light is usually more powerful than the fill light, with the differences between the two intensities expressed as a ratio.

    1:1 – Fairly flat lighting, provides nice clarity but lacks drama.

    8:1 – Almost no fill, this is very contrasy and moody lighting setup.

    Can create fill light by bouncing key light back onto subject at 90 degree angle from key light.  You can vary the intensity of the bounce fill by moving the material closer or further from the subject.  Be sure to get this light into the subjects eyes.

    Specular Highlights, or catchlights, are the most importnat aspect differentiating good portraits from great portriats.  Always bounce the light into the eyes to achieve these catchlights.

    Rembrandt Lighting

    Dramatic lighting style achieved with a 45 dgree off axis light (X and Y).  Known to create a complete triangle on fill side of face.  Drama, but natural.  This lighting will accenturate facial texture, so good for young men, but not always great for women and older people.  Not good for people with small or flat noses, so be sure to read the face of the subject.

    To achieve perfect Rembrandt, you want the shadow from the nose to barely touch the shadow from the cheek,  The triangle formed should be as tall as the nose, and as wide as the eye.  Make sure there is a catchlight in each eye!

    Often times, you will want to bounce the light in the fill side of the subject, use a fill card or a faint fill light.

    Butterfly and Loop Lighting

    Probably the most useful lighting pattern, loop lighting and butterfly patterns are flattering and versitile

    Loop lighting  makes almost anyone look great.  It is viewable by the small shadow it makes under and just to the side of someone’s nose.  Its called loop lighting because the way the shadow loops around the nose.  It is a bit higher than Rembrandt, a bit more intense, and a bit softer.

    You can move from Rembrandt to Loop lighting by having the subject turn slightly towards the key light, or move the key a bit towards the centerline of teh subject.  Next, use some fill to even out the side of the face.

    Loop lighting is flattering for both men and women, where as Butterfly lihghting is a bit less flattering for men.

    Butterfly Lighting or Paramount Lighting or Glamour Lighting is the perfect lighting for young women.  It gets it’s name from the small butterfly shadow just under the nose.

    To set it up, raise the light up fro the loop lighting position and move the light directly in front of the subject.  Adjust the camera as necessary, and use a lighting stand with a boom if possible.

    Look for the definition in her cheek bones and the shadow under her chin.

    If you use a fill with butterfly lighting, it becomes clamshell lighting or glamour lighting.  Try different ratios for very pleasing effects.

    Split Lighting

    Splits the face right down the middle, into a light side and a dark side.  Place the light 90 degrees to the side and at about the same height, maybe a bit above.  You can even try moving it somewhat behind.

    With most women, you want to keep the light in front of the subject.

    Super dramatic and dangerous.  Use reflectors to fill in, but do subtlly.  Split lighting at a low ratio creates a less dramatic look.

    Lighting Positions

    These differnt postions combine with the different patterns to bring complexity and variety to your portraits.

    Broad Lighting

    Side of teh face with the most light, is closer to the camera.  Side of face with shadow is away from camera.  This makes skin look even, but face looks wider, so use carefully.

    Short Lighting

    Side with most light is away from camera, while side with shadow is facing camera.  Makes subject slimmer, but it accentuates texture, making it more useful than broad lighting, but stil use with caution.

    Rim / Profile Lighting

    Short lighting to the extreme, the camera shoots almsot into the key light, so you have to watch for light flares.

    Two Light Setups

    The most common way to use the 2nd light is as a fill light.  When using a light to fill, you can finely tune the fill on the subject.  You also get to use modifiers for the 2nd flash to change things up even more!

    Start with a soft fill light.  You never want to create more shadows with your fill, you only want to control the shadows you already have.

    The ratio between the different flashes determine the amount of drama and texture in the image.  A high ratio makes the shadows more pronounced, increasing drama.  Most common lighting ratio is 2:1, with key twice as intense as fill.  Low ratios make the image flat.

    Three Light Setup

    This third flash is most commonly used as a hair light.  Adds highlights to the subjects hair to give them background separation.  This light spills onto the shoulders to define the shape.  This is especially useful if dark subject is on dark background.

    Hair lights are placed about 45 degrees behind the subject and pointed towards the shoulders, giving them a glow.  It is on the same side as the key light.

    Rim lighting creates a thin line of light that traces on subject, separating it from the background.  For this effect, we want the flash to occur behind the subject, completely hidden from view.

    Kicker or Kick lights separate the subject from teh background by adding highlight to fill side of face.  Move your kick light 180 degrees off the key light.  You don’t want to light up the fill side of the subject, you want to skip the light off the side of the subject and into the camera.

    Start with a low power and try to make the flash as narrow as possible.  Worst thing ever is for light from kick to enter camera, resulting in flare.  Can sometimes bring fill light down to give the kick a bit more expression.