Canon G10 with dual Sea & Sea 110a strobe problem

I have a G10 in the Fisheye housing with dual Sea & Sea 110a strobes. i believe i have a TTL issue. most pics are underexposed. both strobes seem to be firing but still not enough light. i have set up the strobes exactly as indicated in the Sea & Sea manual with them set in the TTL mode, slave switches on, and full on the intensity dial. The camera is set to forced flash, 1st curtain. i have tried different iso's and f stops to no avail. My wife has the same camera and housing but with the Inon S2000 strobes. If we shoot the same scene with our cameras set up exactly the same, her results are much better exposed. The cameras shoot the same otherwise.

i use dual optical connections, one each from strobe to housing. i tried a test where i took a forced flash pic of the front of the strobes with the optical connection removed from from the strobes. when the strobes were set in TTL, both strobes fired but my resulting pic did not show the blinding flash. When i set the strobes to the "manual 1" position and did the same, both strobes fired and i got the bright flash on the resulting pic. does this mean i will have to use the strobes only in the manual position and adjust output each time ?

any help with this would be appreciated

Your strobes are flashing in sequence with the Canon pre-flash. They are not firing with the "actual" flash.

I am sure someone can tell you how to have the strobes ignore the pre-flash. They'll post the answer soon.

Your strobes are flashing in sequence with the Canon pre-flash. They are not firing with the "actual" flash.

 

I am sure someone can tell you how to have the strobes ignore the pre-flash. They'll post the answer soon.

 

Thanks. i suspected this. hopefully someone nows how to get around this.

What mode is your camera in?

You need to be in Aperture Priority, Shutter Priority or Program to get TTL on a G-Series ... TTL doesn't work in Manual.

What mode is your camera in?

 

You need to be in Aperture Priority, Shutter Priority or Program to get TTL on a G-Series ... TTL doesn't work in Manual.

Yes i am using aperture or shutter priority only

Yes i am using aperture or shutter priority only

I am not an expert - but I do have a YS 110 alpha, which I use with a Canon SD900 and a Canon A570. I believe that the A570 is similar in operation to the G10, and I usually put this into P or Av mode, and it works flawlessly. For the SD 900 - I set it to M mode, and then lock the flash to on and the ISO to 100.

The YS 110 alpha is designed to mimic the preflash and the main flash - rather than simply cancelling the preflash - so my understanding is that it functions in exactly the same way as the Inon S2000.

You seem to have all the settings correct - I would start with one flash connected - and take a picture of yourself in a mirror - with the fiber optic cable connected - and then see if the strobe shows firing in the picture. Try this with your wife's rig as well - as they should operate exactly the same.

If the picture with the Ys 110 alpha is simply underexposed - you can adjust it with the camera's flash exposure compensation function - up to plus or minus 2 ev in 1/3 ev steps.

Changing ISO or aperture should only make a difference if you are operating close to the upper limits of power/range of the flash, as the camera will compensate for these settings automatically.

Please let me know how you solve the problem.

I am not an expert - but I do have a YS 110 alpha, which I use with a Canon SD900 and a Canon A570. I believe that the A570 is similar in operation to the G10, and I usually put this into P or Av mode, and it works flawlessly. For the SD 900 - I set it to M mode, and then lock the flash to on and the ISO to 100.

 

The YS 110 alpha is designed to mimic the preflash and the main flash - rather than simply cancelling the preflash - so my understanding is that it functions in exactly the same way as the Inon S2000.

 

You seem to have all the settings correct - I would start with one flash connected - and take a picture of yourself in a mirror - with the fiber optic cable connected - and then see if the strobe shows firing in the picture. Try this with your wife's rig as well - as they should operate exactly the same.

 

If the picture with the Ys 110 alpha is simply underexposed - you can adjust it with the camera's flash exposure compensation function - up to plus or minus 2 ev in 1/3 ev steps.

 

Changing ISO or aperture should only make a difference if you are operating close to the upper limits of power/range of the flash, as the camera will compensate for these settings automatically.

 

Please let me know how you solve the problem

Thanks for all the responses. i have now set the internal G10 flash to "2nd curtain" this appears to work on the surface. I will dive it and find out. i will also try the pic in the mirror with both setups.