problems with flash sync?

[deedspender]

hi !!

cannon 300d with portaflash 336vm!!

i'm using the built in flash light on the 300d diverted to trigger the 336vm flash unit, the flash unit is fireing in sync with the camera flash, but no light/flash from the unit is visable on the photo !!

is it a sync problem or am i missing something really obdvious?

hope you can help!!
claire!!

sorry its a basic question, but i honestly can't progress if i can't get the basics right!!

any help would be much appreciated!!
thanx!
claire!!!

please don't keep passing me by!! heeeeeeeeeeeelllllpppppp me!!

[robertwgross]

It sounds like you are expecting the built-in flash to optically trigger the portaflash.

In the primary shooting modes of the camera, the built-in flash will put out a pre-flash (which is used for flash metering purposes), and then a tiny fraction of a second later, the main flash will occur. Your portaflash is being triggered by the low-intensity pre-flash, which is not what you want to happen.

---Bob Gross---

[deedspender]

thanx!!
sorry for sounding stupid!!
but can you tell me step by step how to resolve this problem!!

is the 300d compatible with the portaflash unit?
what mode do i need the 300d on to stop the pre flash triggering the portoflash?

thanx!!

[mgbeach]

in Manual mode I don't think the preflash fires.

[deedspender]

in Manual mode I don't think the preflash fires.

thanx!!!
tried all modes, same thing happens !!!

if i place an infa red trigger on the hot shoe and an infa red receiver on the portaflash unit will this sort out the problem?
cheers!!!

[PacAce]

in Manual mode I don't think the preflash fires.
The internal flash cannot be set to manual mode so even if the camera is set to manual mode, the preflash will still fire. The only way to get around this problem is to use an external flash that can be put into manual mode, such as the 550EX or the 580EX.

[RichardtheSane]

in Manual mode I don't think the preflash fires.

Unfortunatly it still does as the preflash is required for ETTL - which is still active in manual mode.


if i place an infa red trigger on the hot shoe and an infa red receiver on the portaflash unit will this sort out the problem?
cheers!!!

Basically, yes it will - as long as you are in the IR rance/position.
I would recommend a wein safe sync on the hotshoe then use the sync chord that came with the portaflash.

[deedspender]

Unfortunatly it still does as the preflash is required for ETTL - which is still active in manual mode.



Basically, yes it will - as long as you are in the IR rance/position.
I would recommend a wein safe sync on the hotshoe then use the sync chord that came with the portaflash.

so let me get this right !!
so the wein safe fits on the hot shoe, the sync chord slots into the wein safe and back to the flash unit?
am i right to presume the first flash from the portaflash can
trigger any other light units i may wish to use?
do you know where i may be able to purchace a wein safe?

many thanx!!
claire!!!

[DavidEB]

Use the flash exposure lock button. Your modeling flash will then be separated from the exposure by several seconds, allowing your optical slave to fire twice (once with the modeling flash and once with the real exposure).

the camera will adjust the on-camera flash intensity based on what it sees in the modeling flash, which will be the on-camera + the slave. So the on-camera flash will be too dim in the final picture. You can fix this several ways -- cover the slave when pressing FEL, or dial in +2 stops FEC for the on-camera flash. Or plan on having a low-intensity front flash and the main light from the slave(s).

You can get some great shots with this technique.

good luck,