Can't turn off flash in Manual mode?

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StuartV Junior Member • Posts: 35
Can't turn off flash in Manual mode?
1

I have an a7rIV. I put it in Manual mode. I have an optical TTL-capable flash trigger in the hot shoe.

It won't let me turn off the flash. It says that option is not available in Manual mode with AutoISO. Not sure what it does if I set an explicit ISO. I didn't try that.

But... What the heck? Manual mode and I can't turn off the flash??

Further - I don't have any strobes turned on, to be triggered by the optical trigger. Looking at the Live View, what I see looks like what I want. But, when I release the shutter, the image that is captured is not the same. It looks not as bright (and seems to have a bit of a red cast to it, that is not evident in the Live View). The trigger itself just has 2 little LEDs that connect to optical sync cables that connect to external strobes, so it is flashing those little LEDs, but they aren't visible to anything.

I think what is going on is that the camera is "firing" the strobes and compensating with the AutoISO so that the exposure is not what I want.

Thus, I want to be able to turn the flash off in the menu settings.

At this point, you may be thinking, "well, why not just remove the flash trigger, or turn it off?" And the answer is, this is my underwater housing setup. The flash trigger is put in the hot shoe and the whole thing is sealed inside a housing. So, I cannot remove the flash trigger or turn it off during a dive. I can manually turn off my strobes during a dive, but turning off 2 strobes is more of a pain than having a custom button on the camera to simply turn the Flash on and off.

Any thoughts? Am I missing something? Any thoughts on why the exposure on a test shot doesn't match my Live View (i.e. is my thinking correct on that, or is there something else going on?)

Thanks!

 StuartV's gear list:StuartV's gear list
Olympus OM-D E-M10 Sony a7R IV Olympus M.Zuiko Digital 14-42mm 1:3.5-5.6 II R Olympus M.Zuiko Digital ED 14-42mm F3.5-5.6 EZ Olympus 14-150 F4-5.6 II +2 more
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