Lighting, when it comes to flash, is a whole different language for photography. You can speak it (on-camera flash) or be fluent in it (off-camera flash) and even then there are varying levels of proficiency. By no means am I an expect or profess to know everything, but rather I’m a lifelong student who wishes to share what I’ve learned so far. For the most part I’ll be focusing on the Canon Wireless Flash system, in other words, triggering your Canon Speedlites using the built-in Canon flash trigger. I’m going to assume that you have a basic, intermediate, or even advanced understanding of off-camera flash, why you are or should be using flash that way and the general concepts of lighting. If not, I suggest that you check out David Hobby, better known in the photography world as Strobist, and his amazing blog on off-camera lighting here. You can start the Lighting 101 lesson here.
In order to get the full benefit out of this series of posts, you must use Canon and also use Canon Speedlites. For those who use Nikon and Nikon Speedlights, go buy Joe McNally’s The Hot Shoe Diaries or attend one of his workshops. You guys are fortunate, you have Nikon CLS (Creative Lighting System), which is phenomenal. For the rest of us who are already using PocketWizards, Elinchrom Skyports, Quantum FreeXWire, RadioPoppers, and/or a host of eBay wireless transmitters, let me introduce you to the world of E-TTL wireless flash and offer reasons of why you should add this to your arsenal of tools.
Canon Wireless Flash System – What It Is
The Canon Wireless Flash System (CWFS) is the system used in all Canon Speedlites that allow Speedlites to be remotely triggered wirelessly (read more information on the Canon Professional Network). There are actually two components to CWFS: wireless triggering and ETTL. The first thing you need to know about CWFS is that you can trigger mutliple Speedlites in ETTL or full-manual mode, the how will come later.
Canon Wireless Flash System is only available with EX-series Speedlites so if you own an older generation Speedlite, the EZ-series, you will not be able to take advantage of E-TTL, thereby reducing the usefulness of CWFS. At current writing, there are only three Speedlites that can act as “Master”, meaning they can control the settings and functions of the other Speedlites, which are: Canon 550EX, Canon 580EX, and Canon 580EX II. You need at least one Master-capable Speedlite to trigger other Canon Speedlites.
The E-TTL Advantage
I’m a huge fan of PocketWizards, owning three Plus II as well as the Sekonic L-358 light meter with the PocketWizard built-in trigger. You could be a block away, hide them behind doors or walls, and still trigger them. My other photographer uses Elinchrom Skyports as well as many other photographers. You can’t go wrong with either. Unfortunately, the biggest problem with remote radio transmitters such as the PocketWizard and Skyports is that you have to run in full-manual on both camera and flash. In studio environments where the lighting remain constants, it’s not much of a problem. Outdoor photography is the challenge especially when trying to balance ambient with flash as the ambient lighting is almost never exactly constant unless your flash is proving 100% of your light, otherwise known as “overpowering ambient”. Shooting in full-manual requires your subject to occupy the same constant distance from the flash or risk under-or-over-exposure. And if you have more than one Speedlite and want to use different power levels, you have to manually dial in the power setting on each Speedlite. There has must be an easy way! Enter E-TTL.
The advantage of being able to use E-TTL with off-camera flash is ENORMOUS. Here is just a small sample of what is possible with using the Canon Wireless Flash System:
- Let the camera do all the thinking, you set the aperture or shutter speed and the camera does the rest
- You can use Aperture priority (Av Mode), Shutter priority (Tv Mode), or God-forbid, Program (P Mode)
- High-speed sync (go beyond the max-shutter-speed of 1/200th or 1/250th)
- You don’t have to spend an extra $100-$200 for additional triggers on top of the ~$200-$400 price tag of each Speedlite
- Put Speedlites into Groups and trigger them at different power levels
- Control Groups, power level, switch modes on all the Slave Units from the Master Unit
So how does all that help you? Let’s try some practical examples. I love to use fast-glass such as the Canon EF 85mm f/1.2L II USM especially wide-open on sunny days for the beautiful subject isolation it can produce with flash for fill on the subject’s face. That usually means shutter speeds of anywhere from 1/4000-1/8000 of a second shutter speed. Using the Speedlites with radio triggers means that I’m stuck at 1/200th or 1/250th (depending on your camera) of a shutter speed or risk black bars in the pictures from the shutter curtain opening and closing at various points throughout the frame. That means instead of being able to shoot at f/1.2, I’m either forced to move to a shaded area or increase my aperture to at least f/6.3 to get a shutter speed of 1/200th or 1/250th; either cases are not very appealing. But by using CWFS, I can take advantage of high-speed sync which will let me use the flash up to my camera’s maximum shutter speed. Keep in mind, depending on how bright it is outside, you can have this same exact problem even photographing at f/2.8.
Here’s another example of how CWFS can help you. You have 10-minutes to shoot a couple’s engagement photos and they want to photograph with as many different backgrounds as possible outdoors at a park. Factoring in walking time and developing shoot locations (if you didn’t scout beforehand) leaves you with a realistic time of 5-7 minutes. Imagine how long it would take to set up an off-camera flash on a stand, take a guess at aperture and shutter settings, take a test shot, and make adjustments and then shoot a couple frames, move to another place and repeat the process. With the Canon Wireless Flash System, my off-camera Speedlite set to Slave, I set my camera to Aperture priority and decide how much depth-of-field I need and take the shots and move on to the next place and repeat.
By using E-TTL for lighting, the camera sends important information to the Slave Speedlite(s) such as distance information so the Slave unit knows how much power to fire to get proper exposure. If your subject moves further away from the Slave unit, more flash power will be applied to compensate and likewise if your subject or Speedlite moves closer together.
There are countless other examples I can give, but this gives you the general point of the E-TTL advantage.
But My Remote Radio Transmitters Do E-TTL Already
There are a number of companies who has expanded their remote radio triggers to do E-TTL such as PocketWizard’s Flex, RadioPopper’s X-series, and Quantum’s FreeXWire. Each of those remote radio triggers are amazing and they each have problems of their own. Most notably with the PocketWizard Flex is that using a Canon Speedlite 580EX II causes radio interference resulting in severely limited triggering range. Also the Flex cannot do groups (they call it zones) without an extra device. For the most part, from what I’ve seen, they seem to work well. But here’s one thing to consider: cost and product infancy. The Speedlites already cost a fortune and to spend another $100-$200 on top of that cost can get very expensive, very quickly.
Why not take advantage of a system that is OEM and offers many functions that these other radio remote triggers are selling to you? Also remember that PocketWizard, RadioPopper, and Quantum has to translate the secret code being transmitted from camera to flash that holds all the E-TTL information, necessary for the flash to fire with the proper settings. I would rather remove the middle-man and let the camera and flash speak directly to each other, less to get wrong that way in my opinion.
Also, this may seem trivial, but more detached parts mean more to lose and more to haul around. The Speedlites aren’t exactly tiny equipment and as you tack on more stuff such as transmitters, it can get cumbersome. I rather save the space in my bag for spare batteries.
The Headbanging Limitations of Canon Wireless Flash System
So I brought a few points of why to use the CWFS and it would only be fair to discuss the issues that I’ve come to experience with it also. Most people are aware that the Master unit fires the flash as part of the exposure of an image. In 99.9% of the time, I set the Master unit to trigger-only meaning that the flash emitted from the Master unit triggers all the Slave units but has no bearing on the final exposure of an image. Unless otherwise stated, what I discuss below is with the Master unit as a trigger-only.
The biggest issue is the Slave seeing the Master signal and there are multiple parts to this, so I’ll tackle them one at a time. The first obvious problem is the Slave unit’s receiver doesn’t see the flash emitted from the Master unit because it’s out of line of sight. For example, behind a model as a highlight. There are a couple of ways to solve this. If you are close enough to wall that is semi-reflective, you can bounce the Master unit’s emitted flash off a wall and position the Slave unit’s sensor towards the same wall and it should trigger. This doesn’t always work as sometimes you’re not near a wall and/or it’s not reflective enough. The second trick, devised by the clever Joe McNally, works more often than not as you put your Master unit on a off-camera flash sync cable (OC-E3 at B&H Photo Video or Amazon.com) and have it held in a position where the Slave unit will see the emitted flash. Here’s another trick that works if the above two aren’t working. You could try the two tricks again BUT zoom the Master unit to its maximum blast of 105mm thereby concentrating the intensity of the burst which may give you that little bit needed for the Slave unit to “see” the information. Trigger in blazing hot, direct, daylight sun? No problem. I have this product that I can sell to you for a very low and limited price of $199.99 each called a Sto-Fen Omni-bounce diffuser. Kidding aside, you can purchase them for $19.99 each at B&H Photo Video or on Amazon.com for $14.20. Stock up on these as they are invaluable and are easily lost. The beauty of these things, they aren’t only for softening or diffusion, but rather they “capture” the light so that the Slave units see the flash emitted. I use these ALL the time, especially in direct sunlight and my slaved Speedlites have never failed to fire. The Sto-Fen also helps when you have two Speedlites on each side of your Master Speedlite. Turning the head to one Speedlite will cause the other not to fire because it can’t see the flash being fired. Here’s a picture to illustrate the point:
In both cases, the flash fired, but notice how with the Sto-Fen on, you can actually see the light fired (left picture) but in the picture on the right without the Sto-Fen it doesn’t look like the flash fired when it did. I can get Slaved Speedlites to fire 50+ feet away with the Sto-Fen on (video coming soon to prove this point) but would be lucky to fire a single Speedlite from ~25 feet without a Sto-Fen and zooming the flash to 105mm!
Another big issue many complain about with the Canon Wireless Flash System is Canon’s choice to use a Ratios System for working with Groups (A, B, and C) of Speedlites. Unlike Nikon’s CLS where each Group’s individual power can be set, you set Group A and B in relation to each other. The choices are 1:1 (equal power) to 8:1 (Group A is 4x more powerful than Group B) and 1:8 (Group B is 4x more powerful than Group A) in 1/2th stops of power. See the chart below to understand:
|Output Ratio (A:B)||Difference in output|
|8:1||A outputs 8X more light than B (a three-stop difference)|
|4:1||A outputs 4X more light than B (a two-stop difference)|
|2:1||A outputs 2X more light than B (a one-stop difference)|
|1:1||Equal output (no difference)|
|1:2||B outputs 2X more light than A (a one-stop difference)|
|1:4||B outputs 4X more light than A (a two-stop difference)|
|1:8||B outputs 8X more light than A (a three-stop difference)|
You do get to set Group C’s power independently of Group A and Group B. The reasoning in Canon’s world is that Group A would be key light, Group B would be background/kicker/highlight and Group C would be hair highlight. At one time I hated the Canon’s Ratio System, but once I learned how to exploit it and make it work for me, I’ve found it not to be bad as I thought it was.
I will be doing a post on the Speedlite Transmitter, ST-E2, in the near future. What you need to know about it right now is do not get it, it’s not worth the money and I’ll explain why in that post.
Sum It All Up
So if you’re new to or have used Canon Wireless Flash System briefly, you should now have a bit better understanding of how this can effectively work for you. Keep in mind that CWFS is not the end all solution to all your lighting needs. There are many cases where remote radio triggers will be your lifesaver such as situations where the flash is placed so far out of view, it can’t see the flash from the Master unit. But in many, many cases, CWFS let’s you work so much more fluidly and quickly as you take advantage of all that fancy metering technology in your camera you paid good money for.
So here’s the gist of what we discussed above:
- Using Canon Wireless Flash System, you can use Aperture, Shutter, Program, or Manual modes and utilize the beauty of E-TTL. E-TTL controls the power output of your flash based on thousands of calculations by your camera. Let the camera do the hard work for you.
- With the Canon Wireless Flash System, you can use high-speed sync which will let you exceed the max-sync speed of 1/200th or 1/250th of a second.
- Because the Canon Wireless Flash system relies on light being emitted, it does have some shortcomings, but through creativity and ingenuity, you can make it work for you.
- Buy a couple of Sto-Fen Omni-Bounce Diffusers for all your Speedlites. Extremely valuable, especially if you plan on using flash in broad daylight or direct sunlight. Get it here and/or here.
- Buy a few Canon OC-E3 cables. You’ll need it in some cases where you need to get creative with your Master unit. Get it from B&H Photo Video or Amazon.com.
- Canon Wireless Flash System may not solve all your problems, but will certainly help you tremendously.
In the next post about CWFS, I’ll be going over some of past photo shoots, our lighting setup, and how CWFS worked for us.