Optical Slave Flash Trigger Unit with 650d

i have a canon 650d and am trying to trigger my vivitar 283 (old but good)with an optical slave as an off camera flash (as im scared to try it on the camera it case it blows the camera} the vivitar does go off but when i check the pic it has not fired at the right time.
I have tried different shutter speeds (very slow to fast) and have tried shooting in manual focus,in case it was from the double flash for focusing in auto. Any help would be appreciated.

thanks john

are you getting black bands? what exact shutter speeds are you using? hows your flash menu setup?


might be as simple as a sync speed issue or you might just have a crappy slave sensor. Make sure the sensor can see the flash from the camera.

If you are triggering it with the onboard flash, it is firing on the ttl pre-flash.

and you should be scared of putting on a modern camera I believe. Definitely verify the trigger voltage before trying it.

it is firing but not in sync i think
Ps no black lines

how do i sink

Try this. Press the flash exposure lock button (*). The on-board and 283 will both fire with the pre-flash. Wait for the 283 to recharge. Take the picture. This assumes you're not in wireless mode.

but im shooting in full manual so there is no preflash for exposer

Just forget the optical slave and pickup radio triggers, it will make your life way easier.

jcdavo wrote in post #15725035
but im shooting in full manual so there is no preflash for exposer

Your talking the camera is in manual mode.
OVF is referring to your popup flash being in eTTL mode and issuing a preflash. Some Canon cameras allow your to place the popup in manual mode also and eliminate the preflash, but your camera is not one of them. By doing what OVF suggested you wil force the preflash to fire and your flash will fire also, then wait for the flash to recharge and take the picture. The popup will not preflash again and your optical slave will fire in sync with the camera.

But forget all this. Buy a set of wireless triggers for about $30 and some change like maverick suggests and get on with it. Optical triggering with a popup flash is going to drive you nuts.

dedsen wrote in post #15725897
Your talking the camera is in manual mode.
OVF is referring to your popup flash being in eTTL mode and issuing a preflash. Some Canon cameras allow your to place the popup in manual mode also and eliminate the preflash, but your camera is not one of them. By doing what OVF suggested you wil force the preflash to fire and your flash will fire also, then wait for the flash to recharge and take the picture. The popup will not preflash again and your optical slave will fire in sync with the camera.

But forget all this. Buy a set of wireless triggers for about $30 and some change like maverick suggests and get on with it. Optical triggering with a popup flash is going to drive you nuts.

exactly.

The 650D/T4i has a manual flash option for the built-in flash. Just go into the flash menu and select "Manual Flash" instead of "E-TTL II". The pop-up flash will then fire without a pre-flash and your optical slave will fire correctly in sync.

Check out page 217 of the 650D/T4i manual.

thanks for all the replys