How can I test the ttl performance on a strobe with a film camera?

[Larry C]

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.

 

[smellzlikefish]

Borrow a light meter?

Whenever I adjust my strobe setup, I always try them in my spare bedroom first. You can also try shooting a macro lens at something like a white vs. black piece of paper and see if it overexposes the white or brings the texture out on the black. Of course, with film you will need to get the rolls developed. Maybe use old film that has been sitting in the back of your closet for this.

 

[Larry C]

When I test with my digitals, it's easy. I just take multiple shots with the same settings and then move the settings up and down the scale. I was hoping that if I used the digital with an open shutter in a dark room and fired the strobe with the film camera at different settings I could see the difference on the digital just as though I had synched the shutter. Maybe I'll try it. I'm thinking if I use a pen light to light a different object for the film set-up to focus on and train the strobe on what I've got the digital pointed at, the pen light won't cause a change in lighting on the picture.

 

[bvanant]

I think a flash meter if you can get one is a good bet, but if not then get a digital oscilloscope app (typically used for music) and use that (cheap enough but way too much fun i.e. it eats time to play with). If your film tests are inconclusive I have a good sekonic flash meter you could borrow.
Bill

 

[Larry C]

Experiment was quite successful. Unfortunately, TTL wasn't. I sealed a Costco milk box and cut a hole in one end for my 10-17. At the far end of one side, I cut a hole for my YS-110. I took a couple of shots unlit to make sure the D300 would shoot set at 2 seconds with smallest aperture. Got a nice dark box with a couple of pinholes of light. Turned on the F100 (empty of film) inside it's housing with strobe connected and focused on a roll of tape in my dimly lit kitchen. Started at f2.8 1/15th and went through each step on the aperture, down to f32, then went through each step on shutter speed down to 1/250th. I got pretty much the same well lit box every time.
Then I set the strobe to manual and made about 12 adjustments, from minimum to maximum output. Went from a dark box with a small lit area gradually to the same picture the ttl settings gave me. Apparently, the strobe fires full blast when connected to the F100 and set on ttl, no matter what the settings. We'll see how my pictures came out and that should give me a good idea of what my strobe settings should be for various shots. I suspect that most of them will be blown out, as most of the time I was set at 1/60 f8 or 1/60 f11, which typically work pretty well for portrait shots at 80-100 feet depth in NorCal water when I want a natural background. I got pretty good results on my first two rolls with those settings and about 50% strobe on the 60AF-D.

 

[bvanant]

That is a much more intelligent way to do the test, I will have to steal the technique; hopefully you haven't patented it.:cheeky:
Happy New Year
Bill