In this article, I’m going to share with you some buying tips and guide you on how to select your first external flash gun for your photography lighting needs. The article applies to both OEM and 3rd-party Canon, Nikon, Pentax, Sony, or other flash brands.
I’m going to provide some tips and advice when you’re shopping for that first camera flash for your DSLR. Here are some of the common key terms you’ll encounter when reading a flashgun’s specification sheet. The items listed are the specs you should put more consideration to when comparing products:
Why Should I Get an External Flash and Which Flash Should I Buy?
Just to recap from an older article. An external flash gun is a very powerful piece of equipment that opens up a lot of photographic opportunities and improves your resulting photos particularly when available ambient light is unfavorable. By having the option of adding your own light, you can control exposure, contrast, motion, lighting pattern, and ISO noise control as well.
Before we discuss features, I’d assume that you’ve already set a BUDGET for your purchase. As always, the topic of ‘what to buy’ is rarely helpful until you’ve set a reasonable budget to begin with. There simply won’t be many flashes with high-tech controls for under $100, for example. Be logical and reasonable with your budget.
There are many factors that dictate the price of the flash, much of it will be listed in later bullet points, but in general, the more powerful, feature-rich, and reliable the unit, the more costly it will be.
OEM flashes (from the same camera manufacturer as your camera’s brand) will often have a higher price tag than 3rd-party units like Sigma, Metz, Nissin, Sunpak, etc. because of the same adage that the OEM manufacturers spent considerable time engineering their technology, while the 3rd-party companies attempt to reverse engineer the OEM’s blueprints.
That doesn’t mean that 3rd party flashes are inferior to OEM flashes, but expect a higher rate of incompatibility and lower resale value compared to OEM equipment.
There are many 3rd-party flashes that offer features that are NOT available on OEM flashes as well, such cases would put the 3rd-party flashes at better value than OEM offerings.
Power will be the main consideration you should be concentrating on when it comes to flash specification. The power of the flash is rated by its GUIDE NUMBER or GN value.
Without going too technical (not the purpose of this article), you should always choose a flash with the highest GN that you can afford. The higher the GN, the more light the flash can emit. You can always reduce flash output but you cannot increase output beyond what the flash is capable of producing.
Sounds simple, right? Actually, it is!
Here’s the warning though, some manufacturers overstate their GN or skips some crucial parameters when they indicate their product’s GN.
Assuming the flash is producing x-amount of light, the intensity of the light (GN) is affected by how much of that light output is spread out. The more WIDTH the light can cover, the less intense the light will appear. Conversely, the narrower the beam, the brighter the light will be.
Confused? Think of adjustable beam flashlights (like Mag Light flash lights) for a second. The bulb’s light output remains constant as soon as you turn on the flashlight, but if you twist the light’s beam narrower, it appears brighter as the beam is more concentrated on a particular spot. When you turn it the other way and spread the light across a wider area, the light will not be able to reach as far and will appear less intense.
It’s the same with camera flashguns as most flash units have a zoom “head” that switches from wide-angle to telephoto so that the beam of light emitted matches the focal length of your camera lens’ coverage.
Most flash manufacturers rate their GN in meters with the assumption of the film/sensor’s sensitivity at ISO 100 (lowest base setting) using the maximum zoom (narrowest beam) of the flash head.
- Canon 580EX Mark II flash is rated at GN 58 @ ISO 100, 105mm (hence the model 580EX, the lower model 430EX has a GN of 43).
- Nikon SB900 is rated at GN 49.5 @ ISO 100, 105mm. On paper, the SB900 throws out less light (it does, but not that much less) than the 580EX II but the SB900 can zoom to 200mm (compared to 105mm) which makes the comparison quite even.
- Pentax AF540-FGZ is rated at GN 54 at ISO 100, 85mm. On the opposite end, Pentax’s flagship flash can only zoom out to 85mm, if it has a 105mm option, the power will be quite similar to what Canon and Nikon offers as well (GN 56-58 range).
For the name-brand flashes, the top-of-the-line offerings are quite similar and predictable.
Returning to the “warning” statement, some manufacturers bank on folks not studying the ratings more carefully, using a higher ISO or a higher zoom figure to rate their flashes. A flash’s GN will increase if the rated ISO was set to a higher value (ISO 200, 400 etc.) or has when charts compare a flash zoomed at 200mm vs an OEM flash at 85mm, for example.
Just make sure you’re comparing near-identical configuration when checking spec sheets and research online. Some flash units may be rated correctly on paper, but requires special power sources to reach that rated amount or can only sustain that amount of light for a few shots.
The recycling rate determines how much time you have to wait in between flash pops. The recycling rate is often listed in seconds with an assumption of a fresh set of internal (often AA) batteries.
The spec sheet will often show you two sets of numbers (e.g. 0.1 to 6 seconds for the 580 EX II). The lower value tells you how soon you can take the next flash shot if the flash produced the least amount of light output, while the higher value indicates how you long you have to wait before taking the next flash shot after it has produced the maximum amount of light output.
In many cases, the key value to check will be the recycling rate at maximum power. The shorter, the better.
Don’t forget that weaker flashes will tend to recycle faster at maximum power as the same set of batteries no longer needs to feed a large flash tube. However, remember that the larger flash’s maximum output is significantly brighter than the smaller flash’s max output as well. When your small flash hits its maximum output, it’ll probably just be about 70% output capacity of the larger flash, so the larger flash will still give you faster recycling given the same light output.
Get the highest powered flash with the lowest recycling rate using the standard 4 AA battery configuration.
Short note about batteries, the type of battery you choose for your flash can be a HUGE difference maker in terms of recycling rate. Make sure you’re using top-notch batteries that are designed for high-drain devices for your flash.
The key features listed in this section are often standard inclusions to most modern flash guns, however, it’s still good to discuss and understand what these features do.
Modern flashes no longer use a light sensor on the flash unit itself to determine flash exposure but uses a series of instantaneous flash bursts that fires a split-second before the camera takes a shot.
A lot of techno mumbo-jumbo goes on during that split-second we fully depress the shutter button to actual image capture that we’re not aware of and that’s when the flash and camera’s TTL calculation takes place, taking account all the camera settings (ISO, aperture, shooting mode, focal length, etc.), the flash adjusts its power to provide the proper exposure.
There are different prefixes used by different manufacturers but they generally do the same thing. Canon calls it eTTL, Nikon calls it i-TTL, Pentax calls it P-TTL, etc. The execution is the same for all of these flashes.
These complex algorithms are very reliable and consistent for most shooting conditions, particularly when the flash-to-subject distance and in-camera settings change constantly like event shooting, weddings, casual shooting, etc.
Auto-Focus (AF) Assist Beam
Most external flashes offer an external AF-assist beam that is significantly brighter, less intrusive, and more effective than what’s equipped on the camera itself. The AF-assist beam on external flashes often use bright red beam patterns that the camera’s AF sensor is sensitive to. These assist beams can help you lock focus in practically zero light conditions without blinding your subject with a bright flashing beam from your camera’s pop-up flash or AF assist lamp.
Be wary of some 3rd party flash’s barely-usable beam pattern. Ideally, it should be a criss-cross pattern or a gridded pattern to cover the different AF points of your camera. Many 3rd party flashes only offer a center dot or vertical lines, which will not be very useful at all.
As mentioned previously in the GN section, most flashes can zoom in an out automatically according to your lens’ focal length. As you zoom your lens from 24mm to 70mm, for example, the flash automatically adjusts its beam pattern to ensure maximum coverage and efficient light usage. Newer flashes has the capability to detect whether the flash is mounted on a full-frame 35mm sensor camera or a crop-sensor camera to adjust its beam pattern accordingly.
Most, if not all, auto zoom heads can be manually set as well, allowing you to change your light pattern from wide to narrow, depending on the lighting effect you want on your subject.
Tilt AND Swivel
The flash head must be able to SWIVEL left-to-right as well as tilt up-and-down. The
Secondary Featuresability to bounce off nearby walls, and not just ceilings is paramount to light control when the flash is mounted on the camera. I firmly believe that all external flashes should be able to swivel, otherwise, your lighting options are severely limited. Sony’s amazing HVL-F58AM flash takes it even further by adding vertical swivel of the entire head as well – I wish all flashes do this.
The other features are definitely nice-to-have items that may or may not fit your needs. It’s always better to have extra features available than not have them when you finally find a need for it.
Wireless TTL Flash Control
Most top-of-the-line flashes allow you to use the main flash (the one attached to the camera) to control other flash units remotely and wirelessly while maintaining the intelligent TTL exposure computation on each flash unit triggered. In theory, you can link up unlimited amount of flash units wirelessly and control each flash’s output from the “commanding/master” unit attached to your camera.
Mid and lower-end flashes often do not have this ability to control other flashes but are ready to act as the flash units RECEIVING the TTL signal instructions from the main unit while high-end units can act as both the TRANSMITTER and RECEIVER of TTL signals.
The creative possibilities of wirelessly triggering TTL flashes off-camera is only limited by your imagination (and how many flashes you can afford). It is an exciting, useful, and highly-flexible feature that can unleash a great deal of lighting opportunities for all photographers.
Manually Adjustable Power
Many photographers prefer using full-manual control over TTL for repeatable and consistent shot-to-shot exposure, particularly if the flash is used off-camera. The camera no longer communicates with the flash apart from telling the flash when to fire.
Look for flash units that allow you to change power settings in at least half stop increments and allow for adjustments as low as 1/64 to 1/128th of a stop.
Side note: If you only plan to use a camera off-camera in manual power mode, buy a much cheaper manual-only flash instead.
Battery and External Power Options, and Others.
Some flashes lets you use additional external battery sources ranging from AA battery packs to lead-acid battery packs that extends not only how long you can shoot with flash, but also improves recycling speed.
Having a battery pack is highly recommended for fast-paced events that requires your flash to fire at its optimum power output in rapid succession.
High-Speed Sync, Rear Curtain Sync, and Stroboscopic Mode
High-speed sync (HSS) allows you use flash beyond your camera’s shutter synchronization limit (to know more about flash sync, google “Flash Syncronization”).
Rear-curtain sync, also known as second-curtain sync allows you to fire the flash as the shutter closes instead of at the start of the shutter cycle. This mode is often used to capture movement trails and slow shutter speeds.
Stroboscopic mode pops the flash repeatedly at user-defined frequency intervals to record multiple images on a single frame.
I firmly believe that buying a flash and learning how to use it properly on and off camera will open up a lot of photographic opportunities that you may not be aware of and increases your knowledge in light manipulation and control.
Choosing a flash for your needs won’t be as difficult as choosing the right pocket digicam as there are only a handful of options available to flash buyers at this point. If you go OEM, your brand probably offers 3-4 models at the most, with significant price and feature differences for you to make an informed decision.
Third-party flashes will be a little more challenging as reviews and tests are not as abundant as OEM brands and 3rd party flashes often offer different sets of bells-and-whistles that make you think twice when comparing. However, just take note of the key pointers in this article and it should help you narrow down your flash options considerably.
Check out the other camera flash-related articles here after buying your first flash!
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