Every light is Quadralite MOVE X 400. I have shot without pre-flash, and see all the external lights firing with the camera flash properly on time, however it must be slightly before the photo is taken. I thought maybe I could somehow override flash timing with a script.
I still think something must be triggering the quadralite *before* the main flash. I may be wrong, but it would seem surprising if the Canon flash illuminated long enough before the exposure for the quadralite to fire and not affect it at all. The quadralite site (
https://www.quadralite.eu/studio-flashes/343-move-x) does say that the duration depends on the exposure setting (1/800s @1/11/2000s @1/32) so if this were happening, a higher setting might pick up some of the flash.
A second curtain setting would presumably also work if this were what was happening,
but I don't see that option in the Canon manual (edit: There's a "slow synchro" setting mentioned in the manual) and the CHDK setting for that does not appear to be implemented.
The Quadralite FAQ (
https://www.quadralite.eu/faq) under "How to trigger Quadralite flash without a sync cord?" also says "If you use a camera without the manual flash control mode, you can come across some difficulties when synchronizing your studio flash with a shutter. This is because a camera operating in the auto mode triggers a measuring pre-flash before the actual exposure. To avoid this, you should use a photocell of a studio flash operating in the pre-flash skip mode. This will enable you to properly synchronize the flash and the shutter."
(The click to expand function in their FAQ seems to be broken, I had to use dev tools to see the answer
)
