Off camera flash is a simple, effective and creative technique that will all need to master. Lots of information is available on the world wide web. You can get some great tutorials on strobist, Fstoppers and other blogs.
I want to share my technique and view about off camera flash(OCF).
First of all, to master OCF you need to properly understand your various exposition factors such as ISO, aperture and shutter speed. On a given photo, if the flash output remains the same, you can control your global scene exposition with your shutter speed. ISO and aperture will help you not only expose the frame properly but they have huge influence on the power output possibility of your Speedlite. The lower the ISO and the smaller the aperture, the more power output the flash will need to generate to expose your subject properly.
You also need to understand how a Speedlite works. You need to put your ego aside and actually read the instruction manual. You have 5 flash function that you need to understand.
Manual power output is when the user controls the amount of light generated by the flash. You can usually control the power output with a scale that goes from 1/1 all the way to 1/128. Manual output is interesting because it gives you the same quantity of light every time. This function needs for you to control all aspects of your camera all the time and can take more time to setup. The flash fires at the beginning of the exposure (shutter open).
1 speedlite behind subject bounced on the wall to create the silhouette.
E-TTL II mode is where engineers geniuses come in handy. E-TTL means electronic through the lens metering. E-TTL II compares the ambient and the pre-flash light levels of the scene to determine where the subject lies, in conjunction with subject distance information if available. This gives the photographer the flexibility to lock focus and recompose the scene without fooling the flash metering system. This system is perfect for photojournalism style and for quick shooting where setup time is very limited. You can have faith in this system, it works wonders. You compensate the exposure of the E-TTL II measurement via the compensation function. The flash fires at the beginning of the exposure (shutter open).
1 speedlite direct with no modifier on camera right hand held by my assistant.
High speed sync is very useful when shooting images outside in an abundance of light. With high speed sync, the cash can synchronize with all shutter speeds. Normally, the sync speed varies from camera to camera at around 1/125-1/320s. This function sends multiple burst of flash during the exposure of the frame to light the subject properly. This robs a lot of power from your Speedlite so full power will not be possible.
1 speedlite with no modifier in high speed sync to help light the rear of the vehicle.
Second-curtain sync is very useful in low light scenarios. Shooting with a slow shutter and second-curtain sync captures the ambient lighting while allowing you to expose your subject properly with flash and also freeze the motion of the subject. The flash fires at the end of the exposure (shutter close)
1 speedlite with a softboxe camera right on stand.
With OCF comes wireless flash transmitters. There’s an abundance of them on the market. Some are E-TTL and others are just in manual mode. Which one should you purchase?
I will always recommend purchasing E-TTL wireless flash triggers for the following reasons. E-TTL triggers are E-TTL. They can also do high sync speed. You can also use them in manual mode. This way you know that you will not be purchasing another set of triggers down the road. Buy once and buy smart. For Canon, I recommend the Canon 600EX-RT with the speedlite transmitter ST-E3-RT. If you have a series of 580EXII or 430EXII flashes, I recommend using radio popper triggers. I have owned and used Pocket Wizard TT1 and TT5 in the past but I have burnt 4 Canon 580EXII. I then switched to Radio Popper PX and had not looked back until I switched to Canon 600EX-RT and Canon ST-E3-RT. I never had any control or functioning issues with the Radio Poppers. What I dreaded about them is the setup time (bracket plus sliding transmitter one) and the “AAA” batteries needed to power them. All my accessories use “AA” so that battery choice was annoying to me. These latest recommendations are made by my user experience. I would also recommend that you look into the Pixel King TTL triggers for which I heard lots of good things about but I have never used.
The new Canon ST-E3-RT allows me to control the power output of each flash without touching the flashes. You can either rod it on the transmitter itself or in the camera body under the speedlite control functions. It also offers my flexibility with the a range of about 100 feet.
Now that you have triggers for your flash and understand how to control your camera and flash, let’s talk about lighting your subject.
Next week, I’ll write about the 3 most important aspect of light for me.
Keep on reading
All photographs by Montreal wedding photographer Sébastien D’Amour