Sunday, January 11, 2015

Beginner's Guide to Canon Flashes

Left to Right: Canon 320EX, 430EX II and 600EX-RT

Modern DSLR cameras can lull you into a false sense of security. Because low-light performance is so good on modern digital cameras, many forego the addition of a dedicated flash unit. Flash units seem to fall down the priority list for many people... out-ranked by other more lust-worthy items like fast primes and long telephoto lenses. This is a shame; many people make the mistake of going for a fast prime to keep up with equally fast-moving children for low-light situations, but soon find out that moving subjects and ultra-narrow planes of focus don't go well together. What would work well is a dedicated flash unit in these situations, as a bounced flash would provide a gentle splash of light while allowing for the user to stop the lens down for more depth of field, all the while "freezing" movement for the exposure.

It's natural for the uninitiated to be adverse to flash photography because of the horrid results that the pop-up fill flash gives. That all changes when you go to a proper flash unit; with just a bit of instruction you can get amazing-looking results in situations where you would normally have been resigned to high-ISO muddiness, all without getting the deer in the headlights look that the dead-on beam of a pop-up flash gives.

Therein lies the reason why flash photography is a worthwhile pursuit for the aspiring photographer; it's not just about adding more light, but about shaping how it falls on your scene and subject. Flash photography isn't just about modulating brightness, it's about shaping the contrast and directionality of the light as it falls on the subject. Adding a flash doesn't just mean adding more capability to your camera, it will also open a whole new creative path to explore. Naturally, the first question is: which flash to go with first?

The the operative word is "first",as  it's best to stay within the Canon system if you are a Canon DSLR photographer. Yes, there are many third-party options available, most of which are less expensive than the Canon alternatives. However, most inexpensive flashes are not TTL-exposure compatible, meaning that you have to set their power output manually. Think of it in this way: you aren't acquiring a Canon flash so much as you are are the Canon flash system. Eventually you will want to venture out to the third-party brands, but if you are new to the system, it's best to stay within the family while you are still learning.


Canon Speedlite Nomenclature


Though the naming scheme for Canon's flashes seems to bear more in common with the one that BMW uses  than with anything photography-related, there actually is a consistent framework being used. These are the designations used on the more commonly used flash units (ring flashes, etc excluded):

Number: This denotes the power of the speedlite. It's the guide number of the flash at ISO 100 in meters, multiplied by 10. For example, the 430EX II flash has a guide number of 43m in this case. The simple formula for guide numbers is as such: GN = distance × f-number. To figure out your working distance of your flash, input the guide number on the left of the equation and the f number that youtr lens is set up. For example, the working distance for a 430EX II at ISO 100 with a lens set at f/4 is would be:

43 = distance x 4, where distance solves for a value of 10.75m

The higher the guide number, the more power that is available for working in large rooms, bouncing the flash off of walls and ceilings, or using light modifiers such as umbrellas, diffusers or reflectors. The last category is important to note if you plan on using the flash in a studio setting; shooting through diffusion material can reduce the power of the flash by as much as two stops.

EX: This indicates that the flash is compatible with Canon's TTL metering. All modern Canon flashes use this designation, so it's not a particularly useful designation. Again with the BMW analogy: at one time the "i" suffix on BMW's cars indicated "fuel injection" but now its an anachronism because all cars come with fuel injection.

RT: Indicates that the flash has a radio trigger. This is a profession-level feature that lets the flash be triggered off-camera by another RT-class Canon speedlite or by a Canon flash transmitter. More about this below.

ST: "Speedlite Transmitter". Not a flash, but a radio trigger that commands RT-class flashes that are positioned off-camera. At the time of writing, this only applies to the 600EX-RT.

Technical Differentiators


Slave vs Master Flashes: Cameras like the 7D Mark II and  70D can optically trigger slaves flashes by way of the built-in fill-flash. This is a simple and easy way to operate off-camera flash, but it does require line of sight. This is a useful way of triggering an off-camera flash, as the next cheapest alternative is also the most cumbersome one: that would be to use a hot shoe synch cable. Though optical triggering requires a direct line of communication between camera and flash, it also provides greater freedom of movement.

Optical vs Radio Triggering: The 600EX-RT comes with a built-in radio trigger, which can be triggered by another 600EX-RT flash or the ST-E3-RT Speedlite Transmitter. The 600EX-RT is also backwards compatible with optical-only Canon flash units when used as a master unit. Line of sight is not required and the range is greater than using an optical method. If you are using multiple 600EX-RT flashes, you can forgo third-party radio transmitter units such as those made by RadioPopper and Pocketwizard.


Left to Right: Canon 320EX, 430EX II and 600EX-RT


Small  Flashes


  • 90EX
  • 270EX II
  • 320 EX


The 270EX II is the least expensive flash that you would want to use for practical purposes. It's a mini speedlite that is for basic use and comes with little pretense. It has no infrared focus-assist beam, but can use the main flash as a strobe-assist to aid focusing (and which is also an annoying method for the subject). This flash can be tilted to bounce from a ceiling but it cannot swivel from side to side to bounce off walls. It does not have a manual power mode. It can be used as a remote TTL slave using the Canon wireless (light-based) signalling system but it cannot be used with third-party radio triggers.

The 320EX is a newer flash that can be used in two roles. The first is as a traditional flash for still photography, but it also has a white LED to provide continuous light for shooting video. As good as that sounds, it is more of a convenience device than it is a serious tool. While it is adequate for both purposes it doesn't either. The LED continuous light is best used for extremely dark situations; it isn't strong enough to be used as a fill light when there is back-lighting to overcome. The flash mode is like the 270EX; it does not have a focus-assist IR beam, nor does it have manual power mode. Even though there is a zoom-head function, it must be changed manually as there is no automatic option for this feature.

The 90EX seems like an odd choice to include in this list, as the guide number of 9m at ISO 100 is woefully weak for DSLR purposes. However, it is the only one of the group that can be used as a master flash controller when you want to wirelessly trigger off-camera slave flashes. This is useful for one camera in particular: the EOS 6D, which does not include a pop-up flash. If you want to use wireless off-camera flash, the 90EX costs $60 USD or less and is the cheapest (Canon) way for 6D owners to go off-camera. Of course, the 5DmIII also does not include a pop-up flash: you could use the 90EX, but that's a different crowd with different needs entirely...


Medium Flashes


  • 430EX II

The 430EX II is the best choice for people who are new to flash photography and who want to have enough functionality in order to properly learn the craft of creative lighting. The situation is analogous to choosing between a T5i or a 70D; both care capable cameras, but the T5i is designed around automatic use whilst the 70D provides a better platform on which to learn and elevate one's skill. The only relevant missing feature to the 430EX II is that it cannot be used as a commander flash; other than that, it has an infrared focus assist feature, can be used in manual mode and the head can be swivelled and bounced. It is does not support the Canon radio-trigger feature found in the 600EX-RT, but this is not a relevant feature for this price category.

There isn't much of a downside to starting with the 430EX II when you are first learning. Though it is true that the more powerful 600EX-RT is the flash that you will be more likely to use if you move on to serious flash photography, there isn't much danger to "under-buying" when starting with the 430EX II. If your skills do progress to the point that you require the larger flash, the odds are overwhelmingly skewed towards the likelihood that you will require multiple flashes, in which the 430EX II takes a turn from being your main flash to being a secondary one.

Large Flashes


All large flashes can be used as either masters or slaves, and can also accept external power. "Large" is the operative word here, as these flashes will tend to overwhelm a smaller DSLR like a T5i in a way that a 430EX II won't.

  • 580EX II

The 580EX II was the original upgrade of the 430EX II. The two differentiators between this and the 430EX II are more power and the ability to act as a master flash. The first benefit is obvious, but the second is not as beneficial as it seems, as the 7D and 7D Mark II, 70D, 60D, T5i and T3i can use their build in pop-up flashes as master controllers. If you have one of these cameras, it is not strictly necessary to step up to a flash like the 580EXII if you want to do off-camera flash photography.

  • 600EX-RT

The 600EX-RT is the upgrade to the 580EX II. Power went up by a bit but the significant upgrade is the built-in radio trigger. This flash can also be triggered optically but radio triggering has greater range and does not require line-of sight. This (theoretically) eliminates the need for a third-party trigger system like a Pocket Wizard system; it's "theoretical" because of the high cost of the flash itself and because you can pair a 430EX II with some lesser radio triggers (which must be used in manual exposure mode) for less cost. It's rare for casual shooters to buy more than one 600EX-RT at a time, and even weekend-wedding shooters will have to budget carefully for a multi-flash setup with this unit.

The Speedlite 600EX is a version of the 600EX-RT without the radio transmitter. It is designed for use in countries where regulations prevent the use of radio transmitters that use the frequencies occupied by Canon’s Radio wireless flash system.

Concluding Thoughts


Since the focus on this article is on the photographer who is just beginning to dive into the enthusiast realm of flash photography, the choice is simple: start off with the 430EX II. It's the Goldilocks choice of the bunch, offering just enough power for larger rooms, bouncing and shooting through diffusers while not being overly expensive like the 600EX-RT. Even if you don't have an aspirations for diving deep into the craft of creative lighting, the cost difference between the 430EX II and the smaller flashes isn't that great.

After you've chose your tool of choice, the next step is also easy...  head on over to The Strobist, one of the most widely read (and probably most beloved) web series for aspiring  flash photographers. 

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