Is there anyway other than trial and error that I can test the ttl performance of a newer non film strobe on my F100? The Sea & Sea NX100 pro housing puts out a five pin signal with the F100 that my YS-110 responds to, but I have no idea if the output is adjusting or if it just flashes the same every time. I was thinking of trying a longer shutter opening with my D300 in a totally dark room and flashing the strobe at different settings with the film camera to see if there's a difference in lighting. Am I way off base, or might this work? Is there any other way without fancy light duration measuring instruments? I shot my last two rolls of film on ttl, with the second having the camera set to +2 on the metering, so hopefully I'll know a little more when I get the slides and scans back. Hoping there's a better way, as it's costing me two dives, a $10 roll of Velvia and $24 worth of processing per roll for the way I'm doing it now.