Strobist: Canon Flash Sync Modification

If you use small flashes off camera to do portrait and editorial photography, definitely take a look at the wealth of resources available on Strobist. From off camera flash basics, to detailed shoot setups, the do-it-yourself esthetic of Strobist is both educational and contagious. This morning’s post gives a link to the blog of a fellow named Michael Bass, who modifies Canon flashes to add a sync jack.

Not even Canon’s top of the line 580EX includes a sync jack. Canon wants you to use their wireless system. The Canon wireless E-TTL system works well indoors, especially with light colored walls to bounce the signal around. When shooting outdoors wireless E-TTL has a limited range, and having your off camera flashes within line of sight of the master flash is crucial. I’ll talk more about Canon’s wireless system in a future post.

Sometimes a particular setup requires flash placement where firing with wireless E-TTL is not possible — in these cases it’s useful to have a set of radio remotes like Pocket Wizards or MicroSync setup to reliably trigger your flashes.

The only option for using radio remotes with your Canon flashes until recently was to use a hotshoe female to mini adapter. This meant buying a Paramount Cords PW-MHSF1 for $45, or a hotshoe to PC adapter and PC to mini adapter to create the same setup. I’ve had good reliability with the Calumet hotshoe to PC adapters. Beware of metal hotshoe to PC adapters like Hama, as they don’t always work.

Still with me? So Michael Bass will add a mini jack to your Canon flash for $60. This allows you to leave the adapters at home, and just plug your radio remotes into your flash using a $3 mini to mini cord from Radio Shack. Tip: Make sure to get a mono mini cord, not stereo. And hey, Canon, can you please include a standard mini jack on your next $400 flash? Thanks!

Important Tip: When using off camera Canon flashes with the wireless E-TTL system, pressing the shutter release on the camera will wake up a 580EX that has gone into sleep mode to conserve batteries. When an off camera 580EX is hooked up to a radio remote, it will go to sleep and not wake up unless you turn the flash off and on again. A big pain. Just remember to set Custom Function #14 on your 580EX to keep the flash from going into sleep mode, and your problems are solved.

4 thoughts on “Strobist: Canon Flash Sync Modification”

  1. Hi Joe,

    Thanks for the kind words about the Canon Flash Auxillary Sync Mod. I also mod the full line of the Canon units, including the OffCameraShoeCord2, and the ST-E2, as well as the 550, 430, and the older units that are missing this function.

    Besides using this mod to connect a flash to a radio receiver when mounted off camera, for the on camera use (hot shoe), this auxillary sync jack will also allow connection to the radio transmitter without using the camera PC connection, (if it exists). This way you can fire off camera flash units while having a flash unit in the hot shoe (weddings), and not having to rely on the optical or IR triggers (optical slave, or Canon IR)

    I actually use a sub-mini (2.5mm) jack and right angle sub-mini plug as opposed to a mini (3.5mm) jack and plug. The sub-mini jack is substantially smaller than the mini jack, and although the 580 has room inside the foot for a mini jack, the finished mod is much neater using the sub-mini set and my custom cable (coiled or straight). I supply one cord with each mod, additonal cords in custom lengths are also available. The mini jack can only fit on the sloping side of the foot, and then the mini plug tends to hit the locking collar, while the sub-mini jack can be placed in a much neater position without any interference. All the other models can only have a sub-mini jack as there is hardly enough room even for the sub-mini jack.

    When I started this mod, I had contacted Canon Technical Support for help with schematic exploded diagrams, and tried to explain the need for this provision, but was met with the expected “no”.

    On the 580, anyone with minimal mechanical and soldering skills can do the mod themselves, should they want to, and it doesn’t take too long to do, although for the other units, and even the OffCameraCord2, things are way more fussy to fit the jack in place, and for sure, only the sub-mini jack will fit. There just isn’t room for a mini jack without having it external to the flash on a pigtail cord. It also would be difficult to do this mod on an OEM replacement foot and field replace it on all but the 580, as for the other units, the OEM foot is just the shell, and all the parts have to be taken out of one and placed in the other.

    Michael Bass

  2. Hi Michael,

    Thanks for the detailed info. Sub-mini makes sense. The 580EX looks like it was designed to have an extra jack or optical slave, but Canon left it out. I’m glad someone has stepped up to make things work as they should. :)



  3. Hi Guys,

    Im a photography student trying to work out the best way to set myself up with some lights. I shoot on a 5d (and currently have one 550ex), and was thinking about getting x3 580′s or a Bowens esprit powerpack – 3 lights v’s 2, for about the same money.

    But what Im trying to find out (and struggling to find the answers) is;

    I’ve seen on ebay some canon wireless remote’s with receivers (with a handy tripod attachment) but dont know if this is the best route. I dont want to mess around with wires – and I need something that can “see” around walls, do you have any other advice other than this?



  4. Hi Gemma,

    The flexibility of 2-3 small E-TTL flashes is great for setups where you can maintain line of sight between the camera & flash. I use Pocket Wizards with Canon flashes in manual mode when I need more range, or studio strobes when I need a bigger, brighter light source with more choice of modifiers.

    I don’t have any experience with the eBay wireless remotes, but I bet you can find out some good info on these on the Strobist blog or Strobist Flickr group.



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