How to Use a Flash

Flash Photography Tips: How to Get Better Light with Flashes - 42West

An on-camera flash is an essential accessory for photographers who want to enhance their photography. It serves multiple purposes, such as providing extra light in low-light situations, balancing exposures in daylight, capturing fast-moving subjects, and controlling or triggering other flash sources. Furthermore, an external on-camera flash offers greater flexibility and creative opportunities to enhance the overall aesthetic of your visuals, particularly when faced with unfavourable lighting conditions. The advantages of using an external flash outweigh the limitations of relying solely on the built-in camera flash, with the only inconvenience being the need for an additional piece of equipment.

Comparing On-Camera, Off-Camera, and In-Camera Flashes: A Knowledgeable and Neutral Explanation

The term “on-camera flash” refers to a specific type of strobe light, also known as a flash, that can be directly attached to a camera. Despite being called “on-camera,” it is not limited to being mounted on the camera itself. On-camera flashes are often used off-camera as well. This sets them apart from other strobe light sources like studio pack strobes and monolights, which are typically not designed to be physically connected to a camera, except in rare cases involving complex adaptation methods. Furthermore, On-camera flashes generally have their own power supply, although external power sources may be used to enhance performance or extend battery life.

An on-camera external flash, as the name suggests, is a type of external flash that can be used with your camera, especially with Lumix G cameras. Compared to a built-in flash, an On-camera external flash offers superior performance in almost every aspect, except for the fact that it is not integrated into the camera body. The main advantage of using an on-camera external flash is the increased versatility it provides in terms of lighting options. Unlike a built-in flash, which typically produces a flat and unflattering light, an external flash can be detached and used in various ways to achieve more creative and controlled lighting effects. For example, you can bounce the flash off surfaces or redirect it in different directions to alter the appearance of the light. In contrast, when using a built-in flash, you are restricted to the fixed angle from which it protrudes.

The majority of integrated camera flashes are positioned near the lens, which often leads to the occurrence of red-eye when taking pictures of subjects in low-light conditions. Red eye is caused by the dilation of pupils in dim lighting, with the camera’s flash being in line with the lens’s optical axis. As a result, the flash enters the eye and reflects back to the camera from the red retina at the back. To minimize the red-eye effect in portraits, it is beneficial to utilize an off-camera flash positioned at a different angle.

Understanding Guide Numbers, Mastering Manual Usage, and Managing Flash Power and Sync Speeds

To adequately comprehend the automatic technology present in modern flashes, it is essential to first grasp the manual control and manipulation of their power. This involves understanding the concept of exposure ratios, specifically how shutter speeds and apertures interact and complement each other. Despite the availability and common usage of auto-exposure metering for optimal exposure settings, having a firm understanding of manual control remains crucial.

Guide numbers are the standardised, numerical way of determining the power of a flash, a higher guide number represents a more powerful flash. A guide number is the product of multiplying the f/stop of an exposure with a given distance, at ISO 100; or GN = f/number x distance. This calculation directly refers to the Inverse Square Law, which states that a specified physical intensity of light is inversely proportional to the square of the distance from the source of the physical intensity. Since f/numbers fractionally relate to the intensity of exposure, they perfectly fit into the guide number equation as a variable for determining flash exposure. 

To simplify, let’s consider a practical scenario. Imagine you have a flash with a guide number of 100. When photographing a subject 25 feet away, you need to use an aperture of f/4 for the correct exposure. Similarly, a subject 50 feet away requires an aperture of f/2, while a subject 5 feet away requires approximately f/22. It’s important to note that guide numbers are typically specified at ISO 100. If you’re using a higher ISO, such as ISO 800, the aperture needed for a subject 50 feet away would be around f/5.6. Another factor to consider is the flash power. You can adjust the flash output in increments to conserve battery life, improve recycle times, or have more control over your exposure in close-up situations. To account for different flash power settings, you can modify one of the other variables in the guide number equation. For example, if you’re using a flash with a guide number of 100 (at ISO 100), set at 1/4 power and photographing a subject 25 feet away, you would now require an aperture of f/2 (which corresponds to one-fourth of the original aperture in the given example).

It is important to understand that when working with flash, adjusting your aperture is typically the best method for controlling your exposure. Unlike shutter speeds, the duration of a flash is very short, so changing the shutter speed won’t affect the exposure. Only a leaf shutter or certain specialised lenses can handle extremely fast shutter speeds for properly exposing the image.

When using flash, the “sync speed” refers to the highest recommended speed at which your camera can capture an image. If you take a photo with a faster exposure time than the sync speed, the shutter might not have enough time to fully clear the image path, resulting in blocked or blacked-out areas. On the other hand, it is possible to have longer exposures than the sync speed and obtain properly exposed images, but this may have various consequences or advantages depending on the duration.

Optimising Lighting with Fill-Flash and Adjusting Shutter Speed

While flash is often used to illuminate a scene entirely, either because of low-light conditions or because you are using a small aperture to gain additional depth of field, flash can also be used in combination with ambient exposure to provide additional creative benefits. If you’re using a shutter speed that is similar to what would be required of an ambient, regular exposure, in conjunction with flash, you will be mixing both ambient and flash light. This technique is called dragging the shutter and can be utilised to highlight specific objects or subjects within a scene. An example would be photographing a field or bush at dusk; while the foreground and surrounding areas are very dark, there is more light available in the sky regions of the scene. A way of rendering this type of scene would be to use your flash to illuminate the nearer regions, and then let your shutter stay open longer to capture the ambient light of the sky. 

Fill flash is a photographic technique that involves using a strobe to illuminate certain areas of a scene. This can be done to compensate for darker areas compared to the surroundings or intentionally create a darker background to highlight a closer subject. It can be applied in daylight or well-lit conditions, even if the overall exposure is suitable for handheld photography. This technique is particularly useful when there is a difference in exposure values between the foreground and background, such as backlit or silhouetted subjects.

In order to effectively utilise fill flash, it is important to first measure the exposure of your subject and then measure the exposure of the background. The disparity in exposure values between the two areas is what needs to be compensated for using flash. Once the difference has been determined, adjust your camera settings to correctly expose the background (keeping in mind that your subject may be slightly underexposed), and then adjust the flash to account for the difference in stops between the subject and the background. This will result in a more balanced and evenly lit image, with both areas properly exposed. Additionally, this technique can be used to intentionally make your subject appear brighter than the background, emphasising its prominence. To achieve this effect, follow the same steps as previously mentioned but intentionally underexpose the ambient regions on your camera and ensure the flash properly illuminates your main subject. As a result, you will capture an image with a well-lit subject and a darker background.

TTL Flash Metering

When using your flash in manual mode or with a non-automatic flash, you have complete control over the flash’s power and the camera’s exposure settings. This allows for creative flexibility, especially when you are familiar with specific working situations. However, automatic flash metering can be more practical and efficient in certain situations. In-camera TTL (through-the-lens) flash metering calculates the proper exposure by considering variables like flash power and subject distance when used with a compatible lens.

When the shutter button on a camera is pressed, the TTL flash metering system is activated, causing the connected flash to instantly fire. The flash emits a pre-flash of light that hits the subject and bounces back through the lens. This light is then measured by an exposure metre, which calculates the appropriate duration for the actual exposure to achieve proper exposure of the subject. The latest TTL systems have the ability to regulate the exposure settings of both the camera and flash, resulting in accurately exposed photographs and reducing the need for guesswork and trial and error in flash photography.

When using flash photography, the accuracy of the exposure depends on the compatibility between the flash and camera, in terms of their TTL systems. Each camera brand has its own TTL system, like Canon’s E-TTL II or Nikon’s i-TTL, and TTL-enabled flashes are designed to support specific TTL systems. Moreover, modern TTL systems can also work with certain lenses, which helps in achieving accurate TTL metering by considering the distance between the camera and the subject. The flash automatically adjusts its power output based on the focus point, ensuring proper exposure for the subject at that distance. To intentionally over- or under-expose when using TTL flash metering, most flashes include an exposure compensation system, similar to that of a camera, allowing you to adjust the amount of light by a certain number of stops. Exposure compensation, along with dedicated settings, also enables you to control the amount of fill flash when working with TTL, resulting in more precise and consistent flash photography.

Mastering the Technique of Off-Camera Flash Bounce

There are generally two categories of on-camera flashes: those with movable flash heads and those without. Flashes without movable flash heads are more compact, but their practicality is limited compared to those with tilt and rotation capabilities. Flashes without movement act similarly to the built-in flash on your camera, always illuminating in a fixed, forward direction. However, these flashes typically offer more power and manual controls compared to the built-in flash.

Once you have the ability to adjust the position of your flash head, you open up a range of possibilities for effectively controlling and directing the light falling on your subject. Directly pointing the light at your subject typically results in harsh lighting with deep shadows and a rapid decline in light intensity toward the background (as explained by the Inverse Square Law). However, by tilting your flash head, you can bounce the light off nearby walls or the ceiling to achieve a softer lighting effect. When the flash light hits a wall or the ceiling, it effectively transforms into a larger light source than the flash itself, which helps mitigate the effects of the Inverse Square Law. The larger light source produces softer shadows and more even lighting across the scene.

To achieve even greater flexibility with your flash photography, you have the option to detach the flash from your camera and position it in any desired direction. This can be accomplished in two ways: through a wired connection or a wireless connection. For a wired connection, you will need a sync cord that connects your flash to your camera. It is important to ensure compatibility between the connections of your camera and flash. The flash may have a proprietary connection or support more standardised options such as a household plug, mini-phone, photo, or sub-mini jack. These cables usually feature a PC connection on the other end to establish a link with your camera. In case your camera lacks a PC sync socket, there are adapters available that can be inserted into the camera’s hot shoe to provide a PC connection. The cables that connect your flash to your camera are available in coiled or straight designs, ranging from 6 inches to 33 feet in length. When selecting the cable length, consider how you plan to use the flash off-camera. If it’s too short, you won’t be able to move far from the camera, while an excessively long cable might become cumbersome to handle. If you don’t need to hold the flash in your hand, you can easily detach it from the camera and mount it on a stand or a flash bracket. A flash bracket allows you to position the flash to the side or above the camera, providing more freedom in terms of orientation and direction. These brackets typically attach to the camera via the tripod socket and offer an additional means of supporting your camera and flash system.

To connect a flash to your camera, another approach is to utilise a wireless receiver/transmitter system or a slave unit. These systems utilise various triggering methods such as radio, infrared, or optical signals to establish communication between your camera and the flash. Opting for a wireless setup offers you greater flexibility in terms of creative control. The range between your camera and flash becomes virtually boundless, allowing you to position them at considerable distances. Additionally, you have the ability to incorporate multiple flashes to achieve more imaginative and sophisticated lighting arrangements.

Additional Battery Power

As mentioned earlier, a key feature of an on-camera flash is the built-in power source, typically AA batteries, that can be easily replaced during a photo session. While this convenience is preferable to carrying heavy battery packs for portable strobe units, it is important to note that AA batteries are not very powerful. As flash photography requires a significant amount of battery power, especially compared to regular camera batteries, it is advantageous to use an external battery pack for regular flash usage. These auxiliary battery packs are compact and can be carried in a pocket or attached to a belt, connecting to the flash through a dedicated cable. They may contain an internal or removable rechargeable battery, or simply bundle multiple AA or other batteries together for extended battery life. Along with providing longer battery life, battery packs also enable faster recycling times, allowing for more rapid firing of the flash. It is worth noting that the use of external battery packs is often limited to higher-end flashes designed for longer shooting sessions and more demanding conditions.

Key Considerations for Buying a Flashlight

When purchasing a flash, it is essential to consider your specific needs and ensure that it aligns with the intended use and features you require. It is also advisable to choose a flash that is compatible with your camera brand or has camera-compatible accessories and connections, especially when it comes to TTL systems. Not all TTL-compatible devices are compatible with every camera or flash. Additionally, it is important to factor in the build quality of the flash and its ability to withstand the conditions you typically work in. Some flashes come with full weather sealing, which can be crucial for adverse working conditions.

Essential Gear for Enhancing and Controlling Light

When discussing bouncing flash and detaching it from your camera, it’s important to note that the artificial light emitted by a flash and its straight angle may not always provide the most attractive or visually pleasing lighting. Apart from redirecting the light source away from the subject, there are various other tools available to manipulate the way the light interacts with the subject. These accessories, known as on-camera light modifiers, come in different shapes and sizes, each designed to modify the light in different ways.


The primary light modifier that is commonly used to enhance your flash is called a diffuser. There are different types of diffusers available, including bounce, flat, dome, and wide-angle styles. These diffusers work by placing a translucent box or substrate in front of your flash, which helps to create a softer and more evenly distributed light compared to a flash head without diffusion. However, using a diffuser may result in a decrease in the flash’s power by at least one stop. Nevertheless, the light produced will have reduced directionality and a softer appearance, creating a less high-key effect.

Mini Softboxes

A mini softbox, as its name implies, is a compact variant of a softbox specifically created for on-camera flash usage. Its purpose is to transform the light emitted by the flash into a larger and softer source, which effectively reduces the harsh shadows and results in a more diffused and enveloping illumination. Furthermore, the various shapes of softboxes can produce a range of catch lights in subjects’ eyes, while still yielding similar performance based on their respective size or surface area.

Bounce Cards

Auxiliary bounce cards can be utilised for added control and adaptability when the built-in bounce card is not available or does not provide sufficient options. These cards serve as a middle ground between a diffuser and a softbox in terms of light quality. By extending from the top of the flash head, they act as reflectors, preventing light from scattering in all directions and instead creating a larger and softer light source, similar to bouncing the flash off a wall or ceiling.

Grids and Honeycombs

Grids provide enhanced control for your flash, allowing for a more focused and precise light output. The honeycomb pattern restricts the dispersion of light, resulting in a more concentrated and organised beam. Grids are typically offered in various sizes or angles, with smaller measurements indicating a narrower and more precise light spread.


To create a small circle of light, a snoot can be employed, which offers a narrower beam of light compared to a grid. The size of the light circle can be adjusted by utilising a longer snoot. Moreover, snoots commonly have a grid spot at the end, allowing For an even narrower beam angle. Using grids and snoots individually or in combination helps create a harder light quality, increased contrast, and more pronounced shadows by restricting the spread of light.


A flash extender is essentially a lens called a Fresnel lens that concentrates the light from the flash into a narrower beam, allowing it to reach greater distances. It can be compared to using a telephoto lens on your camera, but for your flash. Some flashes even come with built-in telephoto/Fresnel lenses specifically for this purpose. Unlike a snoot, which simply restricts the spill of light, an extender focuses the light into a more concentrated area to replicate the perspective of longer lenses.

Understanding Color Filters and Gels

These particular filters, and commonly the Chief Technology Officer (CTO), are frequently used to adjust the intensity of your camera’s flash in a precise manner. A complete Colour Temperature Orange (CTO) filter alters the flash’s output to around 3200K, which is ideal for tungsten lighting conditions. Conversely, a complete Colour Temperature Blue (CTB) filter transforms the flash’s output to approximately 5600K, suitable for daylight usage (if the flash isn’t already balanced for daylight conditions). If you want to learn more about balancing mixed lighting scenarios, please refer to the in-depth article available on B&H’s website. Additionally, these kits often provide a range of other colours for more creative purposes, allowing you to experiment with coloured light sources instead of relying solely on “white” light. The filters and gels can be attached to your flash in various ways, such as using dedicated filter holders specifically designed for your flash or simply taping the gel onto the flash head.

Understanding Ring Lights and Macro Lighting: A Comprehensive Overview

One other specialised type of lighting is an on-camera ring light, and other types of on-camera lighting are well-suited to macro applications. While all ring lights are technically “on-camera,” these refer to those that feature self-contained power and other features as noted earlier. A ring light is a unique lighting tool that is donut-shaped and goes directly around your lens. This circular light is perfectly aligned with the axis of your lens and helps to provide nearly shadowless lighting since the light is coming from all angles directly surrounding the lens. When used with more powerful studio strobe battery packs, a ring light is a popular tool for fashion and portraiture work, but when confined to an on-camera source the light output is typically fairly limited and best suited to macro and close-up applications. The other, and even more important, the reason that ring lights are best suited to macro work is that they constitute an effective solution that provides even lighting to subjects where your own or your camera’s shadow would be in the way if you were using off-camera lighting. Since the light is positioned on the same plane as your lens, you are able to light anything that your lens can focus on. In addition to ring lights, there are also twin-light setups that position two separate light heads off to either side of your lens, but still on a similar plane as your lens. These dual heads can be positioned to induce a more physical, 3D quality than a ring flash since they can be tilted or moved slightly to create more dimensionality with objects. Finally, there are also twin-light setups that are attached to a ring light to provide the benefits of both systems, including the flat, even lighting of a ring light but with the available dimensionality of a twin-light configuration.

Flash photography opens up a whole new world alongside natural-light photography, offering the ability to enhance and add visual interest to subjects. Unlike natural light, flash brings a unique dimension and texture, providing a level of depth that cannot be achieved otherwise. On-camera flash is a convenient and lightweight choice for adding extra light to your photographs, surpassing the limitations of a flash affixed solely to your camera. By controlling aspects such as power, direction, placement, shape, and colour of the flash output, on-camera flash becomes an indispensable tool for photographers of all levels.

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