Flash with ISO 100

[Mcary]

Thank you, everyone for the information. I know the flash output is correct, so I will have to do some testing on the cameras themselves.

The reason why I mentioned ISO 100 is that I have gotten results using ISO 400, which had made me think the film choice was the issue.

Sorry but what you've posted above and what you've posted previously just doesn't seem to jive.

Previously you've posted that your flash shots with ISO 100 film are coming out underexposed and here you're implying that your flash shots with ISO 400 film are coming out correctly exposed. Then you go on to state that "I know the flash output is correct"
To me correct flash exposure at ISO 400 plus underexposed flash exposure at ISO 100 = Flash isn't putting out enough light/power at the setting used for ISO 100 and need to be set to a higher output level.

 

[antonandreas]

Sorry but what you've posted above and what you've posted previously just doesn't seem to jive.

Previously you've posted that your flash shots with ISO 100 film are coming out underexposed and here you're implying that your flash shots with ISO 400 film are coming out correctly exposed. Then you go on to state that "I know the flash output is correct"
To me correct flash exposure at ISO 400 plus underexposed flash exposure at ISO 100 = Flash isn't putting out enough light/power at the setting used for ISO 100 and need to be set to a higher output level.

It does not make sense to me either, so I was trying to figure it out what the problem could be.

I had been thinking that the ISO was the problem - but I am still not sure because I thought I had taken into account two stops of power. I will however try everything suggested to figure out if it is camera or user error.