Sync'ing issues...

I am THIS CLOSE >--O:--< to getting this figured out...

I am trying to sync two remote flashes (two of Adorama's Flashpoint 620s) to work in my (beginner's) home studio set-up...

The problem I am having is with my 420EX Speedlight (on a 30D) - I am trying to use it to key the other two strobes.

When I snap a picture, everything looks like it all goes off at once... but a quick view of the histogram all of the bricks are in the middle of the histogram and the picture is not very bright...(against a pure-white background).

So, I synched up via cable and still have the same problem (Speedlight is on).

I turn the speedlight off (Sync cables still connected) and get almost all of my bricks in the histogram spiking on the right-side.

So my conclusion (after reading countless threads) is that the Speedlight is keying the Flashpoints either prior to (where I am leaning) or right after the shutter snaps. Is there a setting on the speedlight to make it work as a master sync source?

Thanks,

- Jeff

What shutter speed are you Using? If its above 1/250th you will have rpoblems. Canon recommends you use 1/125th shutter with studio strobes.

Also, your 420 is probably firing a pre flash to get a reading from. The pre flash fire just a few tenths of a second before the shutter opens add is probably triggering you Monoblocs to early.

The Canon 420EX has no manual mode.

So, it always sends out a preflash.

Do these "Flashpoint 620s" flash units have a built in optical slave and are you using that function?

If so, there is no way you can use the Canon 420EX to do what you want. It will trigger the "Flashpoint 620s" on the preflash, so they will not contribute to the gross exposure.

So, you can use the 420EX, or the "Flashpoint 620s, but not both.

The root of the problem is the lack of a manual mode on the 420EX and the need for manual mode usage on the "Flashpoint 620s".

Note, that there is a bit of guesswork on my part as you did not supply enough info to know much about the "Flashpoint 620s" flash units.

The Canon 430EX has a manual mode.

Enjoy! Lon

Does the 420EX have a Custom Function to compensate for that? Ive got the 580 and I think I read something about that.

Or, you can use the 420EX and ONE of your strobes connected via the PC cord unless you can get both of the strobes connected to the PC cord (so that they don't trigger optically).

wilvoeka wrote in post #2743921
What shutter speed are you Using? If its above 1/250th you will have rpoblems. Canon recommends you use 1/125th shutter with studio strobes.

I've gone from 1/200 all the way down to 1/40 - no difference.

And I am using the optical slave mode on the Flashpoints. I guess I could run sync-cords to both of the Flashpoints and take them off of manual (I'll need a "Y" cable, I guess, to connect two of them...) to get all three actually synched...

At least the clouds are parting...

- Jeff