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Need help!! What is causing this change in exposure?

Started Feb 14, 2014 | Questions thread
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Ontario Gone
Ontario Gone Veteran Member • Posts: 4,183
Need help!! What is causing this change in exposure?

New GX7, im playing with exposure values in video and i noticed something. When shooting in A or S mode, i have the ability to adjust exposure comp by up to 3 stops. If i shoot at the maximum ISO of 25k, i can still choose a +3 to exposure comp. This should change either SS or aperture, depending on what mode i am in, but if i am already at the maximum ISO of 25k, and if im already wide open at F1.7 on my lens, what else is there? It can't be adjusting my SS because i have the "no flicker" setting locking my SS to 1/60. However, when i compare videos with and without this +3 exposure comp, there is a clear difference. What is causing this?

Below is an example. Both videos were taken moments apart with no change in ambient lighting. These are screenshots of the two. I had one set to -+0EV and the other to +3EV (it was actually set to +5 but after starting recording the camera changes it to +3 which is shown in the display). Without the ability to alter SS, aperture, or ISO, how is the camera generating this extra brightness?

No PP has been done on either, no sharpening or NR. No exposure adjustment. Incidently, when i do increase the exposure of the darker frame by abaout 3 stops, they look very even. This suggests that the brighter video is indeed receiving 3 stops of gain but from where? Any clues?

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"Run to the light, Carol Anne. Run as fast as you can!"

 Ontario Gone's gear list:Ontario Gone's gear list
Nikon D7000 Canon EOS 70D Nikon AF-S DX Nikkor 35mm F1.8G Nikon AF-S Nikkor 50mm F1.8G Canon EF 40mm f/2.8 STM
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Panasonic Lumix DMC-GX7
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