Learning How to Shoot With Off-Camera Optical Sync

If you have been following Lingua Franca, you probably know that I recently purchased a Yongnuo speedlite to learn about off-camera photography.  To enhance the experience, I also purchased two transceivers from the same Chinese manufacturer.

Snapshot of a Yongnuo YN 565 EX II TTL speedlite. Photo by ©Omar Upegui R.

For several weeks I’ve been experimenting with these electronic toys trying to learn how to use them in my pictorial hobby.  So far I’ve had no problems taking pictures with the Yongnuo transceivers (RF-603C II), using Canon’s E-TTL technology, or using the remote control cable.  Following the owner’s manual the devices performed flawlessly as expected.  So far so good.

There was one option that was a pain in the neck, and that was using the off-camera optical sync feature.  No matter how hard I tried, there was no way I could make the camera talk to the speedlite, even though I did everything the manual said.

When I knew I wasn’t getting anywhere, my last chance was to send an SOS signal to my blogging friend, Joseph Giordano, an experienced photographer from New York.  In less time than it takes to wink an eye, he gave me the following instructions:

“Set your camera to Manual Mode and start with the shutter speed set to 1/60 of a second and use an aperture of f/5.6 to start.  Go into the flash section of your menu on the camera and set your built-in flash to the lowest setting, something like 1/16 or 1/32 if it goes that low.  This will trigger the optical sensor on the external flash.

Set your external flash to Manual Mode and there should be a setting for Slave or Optical trigger mode.  There should be some sort of optical sensor on the flash, so face that in the direction of the camera and twist the flash head towards where you want to light.

Turn your camera On and pop up the built-in flash of your camera and try a test shot, and with any luck, the external flash will fire.

When using any sort of optical trigger you must have two things:

  1. A camera built-in flash to trigger the optical slave.
  2. A remote flash set to slave mode that has a built-in optical trigger.

If you don’t have a flash meter, you will have to guess the exposures or do what photographer call ‘chimping’.  Chimping simply means saying, ‘Oh, oh, it’s almost correct, LOL just like a chimpanzee’.

Two more things.  First, make sure your flash in Enabled by setting it up with your camera’s menu and second, make sure your flash is set to Slave Mode 2.   I don’t know why, but the Yongnuo YN 565 EX speedlite would not work in Slave 1.

If you follow these guidelines, you will enjoy the benefits of using the off-camera optical sync option.  Below are some of the main advantages and disadvantages of optical sync:


  • Low cost triggering system (provided you have a built-in flash attached to your camera).
  • Ease of use.  Not much to know other than the basics.
  • Very effective.  It works!
  • Ideal for controlled environment, shooting portraits, product, etc.


  • Limitations of proximity.  Your off-camera flash needs to see the flash your camera produces.
  • Not recommended in bright sun. If you can see that bright light, so can your flash.
  • Other flashes nearby will trigger your speedlite.  Not recommended for events or parties.

Adam Lerner, a professional photographer, commented the following about this issue:

“There are four basic ways to trigger your off-camera flash. Optical sync, where you trigger the flash with another flash, PC Sync, where you trigger the flash with a PC Sync cable that attaches to your camera and to the flash, Infrared, where you are using an infrared signal to communicate between your camera and your flash, and, Radio, where you use radio triggers to sync your flash. All of these methods work and offer different challenges, pros and cons. The most basic and least expensive may be optical sync, provided you have a built-in flash on your camera.

There are times when you may want your built-in flash to produce more power in order to act as a fill. Why not? It’s another light and may help to get you the look you need for your exposure. I do recommend that when you are using this technique, that you get your main or Key light dialed in before you decide to add power to the built-in flash for your exposure. This way, you are making a choice on how you want your light shaped and not fighting the two lights to make them work. Sounds complicated, well, it is. Lots to consider. So, for the time being, try simply optically syncing your off-camera flash. See how it goes. Experiment with placement, flash-to-subject distance, flash power.”

Below are two images using the off-camera optical sync technique at home.

Take notice that the off-camera flash was placed on the table on the upper left corner of the picture. In my opinion, the subjects were properly lighted. Photo by ©Omar Upegui R.
Photo by ©Omar Upegui R.

Before I close this blog post, I wish to thank Joseph Giordano for his generous assistance in this matter.  Thanks a bunch Joe.  Problem solved, however there is still so much lot to learn to master the craft of good photography.  Good Day

Recommended Reading:  Off-Camera Optical Sync by Adam Lerner

2 thoughts on “Learning How to Shoot With Off-Camera Optical Sync”

  1. Great article Omar 🙂 I am glad to be able to help in any way my friend. Sometime the lack of instructions or even worse confusing instructions make simple matters a lot harder to understand than they should be 🙂

  2. Morning Joe,

    Thanks to your instructions I finally got my camera to talk to my flash. Now I’m doing it almost every evening using my wife as a guinea-pig model to practice the craft.

    Yesterday I received a cheap plastic Sto-fen light diffuser from China. I was very happy with the way it difussed light in a low-lit room. Plan to buy higher-quality diffusers in the future.

    Speedlite lighting is something I would like to practice more in the future. Light is such an interesting and mysterious subject to study for a “wannabe” photographer.



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