I am trying to use the Canon SD700 camera, with the Canon underwater case, and an external slave flash (SeaLife SL960D). The flash fires appropriately in slave mode set to 0 (camera set to flash immediately without pre-flash). However, pictures on-land come out dark with the flash on, and actually lighter and better when I turn off the external flash. It appears that there is some feedback from the flash to the camera that changes camera settings somehow even though it is a pure slave. I tried various manual/scene modes, with different ISO and different external flash strength. Most times pictures with the SL960 external flash turned off come out better! When I turn it back on and take the same picture with the same camera settings the picture comes out very dark. Note that the internal flash is blocked and only used for triggering the slave.
Any ideas?
The slave flash is firing on the preflash from your Canon. The Canon sees a lot of light coming back from what it thinks is the preflash, so doesn't pump out much light with its main flash.
Point the Sealife at your camera and take a picture of the flash. If you look at the photo you took and don't see the sealife firing, then you have a flash that isn't syncing with your camera. If that's the case, you'll need to change the preflash settings.
Cheers
James
The slave flash is firing on the preflash from your Canon. The Canon sees a lot of light coming back from what it thinks is the preflash, so doesn't pump out much light with its main flash.
Point the Sealife at your camera and take a picture of the flash. If you look at the photo you took and don't see the sealife firing, then you have a flash that isn't syncing with your camera. If that's the case, you'll need to change the preflash settings.
Cheers
James
I do see the sealife flash in the picture, though it is hard to tell if it is full strenght at that point or beginning/end of the flas... In any case, the Canon is set to fire once, with no preflash. If I set the sealife to position 1 (fire after 1 preflash) instead of 0 that it is now set, it does not fire at all.
The Canon does not have a permanent preflash option, just "auto-redeye" which apparenty handles red-eye with a preflash only when it thinks it needs to...
Any more ideas?
Opher
Sorry, I misunderstood the flash AND canon manuals... after going through the various preflash combinations in the Sealife it works fine at "preflash setting 2". Sorry for bother...
Opher
Great! Glad you got it working.
I too have this camera and I'm pretty sure you can't disable the preflash so I was stumped.
