Help with S90 and Inon S2000

[abernat]

I have been using this setup (FIX housing with fiber cable) and am now trying to upgrade my skills.

I am having trouble with STTL while using Aperture mode. I have installed CHDK and force the shutter speed to 1/250 (verified in the resulting images). Camera flash is set to AUTO in the menu (but the S90 says you can only have ON, OFF or Night in aperture mode). Exposure is center. Inon is set on STTL.

I cycle through a series of shots varying the aperture while keeping everything else constant. I thought that the images should all have the same exposure for the object I have centered in the viewfinder. But they vary from over exposed at 2.0 to under exposed at 8.0. Flash fires each time.

What am I doing wrong? Or is my experiment incorrect? If so, how should I test this?

Thanks!
Andy

 

[BluewaterPhoto]

hi Andy

Make sure you are doing the test in a dark room ,at ISO 100.. this way only strobe light is getting into the photo. Hope this helps - Scott

 

[abernat]

Thank you replying - I did the checking more carefully and it's clear that my original experimenting was at fault. In a couple of weeks, I'll be underwater with more time to try things out,
Andy