Canon cameras don't sync at the max sync speed when fired with PC cord?

[JohnGerlach]

I have a set of four Canon 600EX-RT Speedlites and four 430EX-RT IIIs.  In the hummingbird workshops I teach, I need a way to let other camera systems fire and sync with my Canon Speedlites.  To do this, I have had to resort to using a Male to Male PC cord.  The cord plugs into the PC terminal on the camera - Canon, Nikon, Minolta, whatever - and then the other male end plugs into the PC terminal of the 600 Master.  When the camera fires the master, the slaves speedlites fire too, so it does work with any system I have tried so far.  However, the max sync speed cannot be used.  Most cameras need to be set at a 1/160 shutter speed and some need 1/125, instead of the more typical 1/200 or 1/250.  Does anyone know why this happens?  I can live with it, but I still wonder why because my clients constantly forget to use the slower shutter speed.

Perhaps someone can think of a better way to use Canon Speedlites-which are superb for hummingbird photography-with other camera systems.  Keep in mind that attaching any device to every Speedlite in the set becomes expensive really quick and requires a lot more batteries as I will be using up to 24 Speedlites at once in six flash stations.  And they take a pounding,  I had one lady today on the hottest hummer station shoot 2000 multiple flash images in 9o minutes.

Any thoughts are appreciated.

John Gerlach

[Waddizzle]

Whoa, sign me up.  Sorry, I have no immediate answers for you.  But, whoa.  What a nice shot.  It's actually smiling.

[JohnGerlach]

Here's a couple more images.  Glad you like it!  The male calliope's wings are blurry because I used a much longer flash duration at 1/4 power.  In the flash station image, I am using the ST-E3-RT controller to fire the Speedlites.

John

[cicopo]

VERY NICE & informative. I strongly suspect the sync speed will be determined by the camera's internals. I don't think it has anything to do with something you can alter. It most likely has something to do with the shutter design or mechanism that  operates it.

[kvbarkley]

What happens when you set the max sync speed? You might be able to use a radiopopper or the equivalent to use a non-canon camera to shoot canon speedilites. My two minutes at the university of google seemed to indicate that.

(Obligatory: Nice Shots! How far away is the camera? What lens?)

[JohnGerlach]

I will try something like that when I find a client that has one.  At max sync speed, you only get a partial image as the second shutter curtain is moving across the sensor, so you lose 1/2 to 1/3 at the bottom of the image.  Some even have to drop the shutter speed to 1/125 second to expose the entire frame.  You don't see this problem often because most of the time the camera knows a flash is being used, but that isn't the case when a PC cord is being used to trip the flash.

Using a Canon 200-400 about five feet from the bird.  They will perch on your finger so no problem with distance.

john

[kvbarkley]

Hmm, can you set the camera to second curtain shutter? Though that might make things worse!

[JohnGerlach]

Haven't tried that and not sure what that would do.  I am wondering if the smart members of this forum could try this for me if they have the equipment. Since a Canon Master can already fire the Canon slaves optically, can a simple wireless trigger be used to fire the Canon Master which then fires the slaves?  I don't need any flash automation, just need them to fire at the manually set power ratio of 1/32.  I know it works with a PC cord, but not sure if a master trigger can fire a remote flash set to master.  I have considered the radio poppers, but don't have the set to try it.  Pocketwizard said it doesn't work that way, but not sure if they have tried what I have in mind.  It seems a shame to have to put a remote on every flash when the Canon master can already fire the Canon slaves remotely.  Sorry if this spins everyone's head around because mine has spun off and rolled down the hill.