The Miracle of Optical Triggering For Real Estate Photography

August 23rd, 2010

In the last few weeks I’ve had several questions relating to the basics of optically triggering flashes while shooting real estate.

Scott Hargis did a post on PFRE  three years ago that is a concise summary of how to approach off camera flash when shooting real estate. However this post doesn’t mention the miracle of optical triggering (frequently referred to as optical slaves). So I thought it might be useful to go over some of the basics of this subject.

Here are the triggering basics (note this works the same if you use Canon or Nikon bodies because everything is manual):

  1. Flashes and camera are all in manual mode: Forget about Nikon CLS or Canon E-TTL automatic modes where the camera talks to the flashes and controls flash power etc. We are not doing that. Everything is in MANUAL.
  2. Optical triggering is built into many flashes: For real estate shooting purposes the most desirable flash is the Nikon SB-80dx. See Scott’s blog for the story on why the SB-80dx is so desirable for real estate shooting. Here are some others:
    • Nikon SB-26 – This is similar to SB-80dx but has only 1 stop power settings instead of 1/3 of a stop settings.
    • Nikon SB-800, 900 – These can be set to trigger optically but these are more expensive than you need be cause they have the electronics for Nikon CLS which you don’t need for real estate.
    • Yongnuo YN460 – This is a relatively new entry to the low price manual optically triggered flash market.
    • LumoPro LP160
    • There are many other alternatives: Here is a site that has more details on other alternatives.
  3. A built-in flash can be used to trigger external flashes optically: For example those little pop up flashes that can be used to trigger a bunch of SB-80dxs. The idea is that the camera body can “tell” optically triggered flashes when the shutter is open. A flash of light is a perfectly good way to do that.
  4. You can mix radio triggers and optical triggered flashes: If you have a DSLR body that has no built-in flash you can use a Cactus trigger to trigger on flash which, in turn can trigger other optical flash triggers. This means you don’t have to purchase a radio trigger for each external flash you have if they can be optically triggered.
  5. Canon flashes don’t have built-in optical triggers: So you’ll have to either use them on camera to trigger other flashes with optical triggers or you can use a Cactus trigger to fire them off camera.
  6. There are many options for alternatives to Cactus triggers: Cactus triggers are just the cheapest alternative. You could use Pocket wizards or many other alternatives instead.

The big benefit of using flashes that have built-in optical triggers is that the triggering device doesn’t have a separate set of batteries to run down and you don’t have to purchase a triggering device for each flash. Simple and inexpensive.

Oh, by the way optical triggering outside is not as effective as it is inside.

Update 8/25: Jake in the comments makes an excellent point. When you are triggering flashes optically from the little built-in pop up flashes or from on camera flashes you have to be careful the triggering flash isn’t pre-flashing. Pre-flashing is a little flash pulse just before the main flash firing to trick people’s retinas into contracting before the main flash fires so the finished photo won’t have “red eye”. You’ll need to either turn off pre-flash (possible on some cameras) or the some flashes with optical triggering (like the SB-26) have a delay setting so they aren’t prematurely triggered by pre-flash.

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4 Responses to “The Miracle of Optical Triggering For Real Estate Photography”

  • I have been using the Cactus V4 radio triggers. They are the latest version, and better made, and VERY reliable. I highly recommend these.

  • You should probably clarify that you can only use a built-in flash to trigger typical optical slaves if it can be set to manual mode without pre-flash. I don’t think any Canon built-in can do this (except for possibly the 7D?).

  • Just so people don’t exclude equipment they may already own, before I got deep into RE photography, I bought my first flash, a Canon 430EX. I later found a deal on a Canon 580EXII and a Speedlite Transmitter ST-E2 combo for a good price. Then I started to learn about using multiple flash, triggering devices and opticals and thought that I had to start all over. With a little experimenting I discovered that I can use my transmitter on my camera to control both of my Canon flashes and add opticals into the mix. So now I use the two Canon flashes and two Nikon optical flashes and the occasional use of my two Morris Mini’s to light just about anything. Because I am inside, I can always find a way to configure the units so my Canon flashes are in a position so the transmitter can talk to them.


  • Those few of us who use Sony Alpha cameras aren’t smart enough to figure out the details of Canon’s mismatched flash “system.” I just remove the HVL 42 flash from my A700’s hot shoe and place it on the master bathroom counter, or anywhere I want to see into a dim background room through a doorway. I keep the flash in Wireless mode all the time, so all I have to do is raise the on-camera flash, which acts as a wireless controller. Neat, huh?

    We Sonoltans also don’t mess so much with HDR. My DRO control, assigned to a custom button for instant access, allows me to dial in just the amount of shadow detail I desire. But doesn’t that create noise? Not that’s visible in a web display. That also saves me the bother of a tripod. I can shoot almost any room handheld, at low ISOs, because I have in-body stabilization, even with my 11-18.

    Of course, if I had a Canon, I’d be better off….why?

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