After doing some more reading and testing I'm still not sure if TTL is working properly, but this is what I've found. Just curious if someone has a link or can explain exactly how TTL works with RX100 and YS-01. All my testing is done indoors.
From my understanding the way TTL works by the TTL sensor averaging to 18% grey. RX100 pre-flashes allowing the TTL sensor to determine how much light is in the scene and when to quench the flash. The camera flash flashes into the optical cable, which passes light to the YS01 and the YS01 quenches based off of the camera TTL.
Does the YS01 also pre-fire when the RX100 flash pre-fires? (meaning does strobe position affect TTL)
Does the YS01 modelling light change the measurement of light from the TTL? (I assume it doesn't because the modelling light turns off when strobe fires, but it's so fast I cannot tell).
How does the YS01 know when to quench? Is it just based of how quickly the light travels through the optical cable and stops? Does the YS01 just start and quench the flash synchronously with the RX100's flash through the light that travels via the optical cable?
Also does the YS01 have a sync range for the shutter speed? Does the shutter speed need to be between 60-160?
If I set the YS01 to TTL do the manual dials still affect the exposure? For example, let's say I set strobe to TTL and have the manual controls on full dump. Do I always get a TTL bright exposure vs a consistent darker exposure if I set manual controls to half dump.
I also usually shooting in either center focus/manual focus and usually have metering set to multi. However, I'm not sure what the optimal settings are. I assume metering type will change TTL, but I would think focus is completely separate from how the TTL sensor captures light.
SIDE NOTE: I'm not sure why, but on the Nauticam cover for the flash there are 2 vertical pin holes that allow the camera flash to shine through. If you have the strobe off and fire the camera flash you'll get horizontal lines that look like the sensor captured an image between curtains.
To Interceptor: Thanks. I got the green light when shooting with some light, but I don't believe the green light went off when shooting at night at f11/2000/iso100. I guess the TTL sensor would sense it's really dark with those settings even if there was indoor lighting.
---------- Post added April 23rd, 2014 at 04:45 PM ----------
After some further testing I think I have a better grasp on how this works, but my previous questions still stand.
Basically I think what's happening in this scenario is that when the RX100's flash is on, the LCD output is brightened up to show what the image would look like post flash. However, if your EV is really low like -2, then it may be in a range where the strobe overcompensates thinking the scene is pitch black. Generally if EV is near 0 TTL behaves normally.
I also noticed there's a plug for the secondary optic cable. I'm not sure if this plug should NOT be covering the secondary optic cable hole. If the camera's preflash is necessary to correctly judge the exposure needed for TTL then the plug may be adversely affecting the TTL sensor. However, not covering the secondary optic hole creates cross lighting if the strobe power is not high.