I am having problems with my Samsung NX11 camera, which I always put in manual mode, when I use it either with my internal a-ttl flash (GN11) or external Samsung flash (GN42) in a-ttl mode.
Problem 1 – scenario: taking a picture of a subject indoors at night, some ambient light from room table lights.
Settings: shutter 1/80, ISO 400, flash distance 2-3m, focal length 50mm, tripod mounted
I then take a series of photos varying the aperture between f5.6 and f22. My expectation is that whilst the subject exposure should remain the same (due to a-ttl) the background will darken as I close the aperture (less ambient light captured). What actually happens is that the whole picture darkens as I close the aperture. Why?
Problem 2 – scenario: taking a picture of a subject indoors at night, no ambient light.
Settings: Aperture f8, ISO 400, flash distance 2-3m, focal length 50mm, tripod mounted
This time I take a series of photos varying the shutter speed between 1/60 and 1/3. My expectation is that, as there is no ambient light, changing the shutter speed should have no effect on the subject exposure. What actually happens is that the whole picture darkens as I reduce the shutter speed. Why a) does the shutter speed have any effect if there is no ambient light b) assuming there’s an explanation for a) does reducing shutter speed reduce exposure when the theory says it should increase the exposure?
As a result of the first problem Samsung agreed to service the camera; I was told they replaced the PCB. However, on testing the camera on its return, Problem 1 remains. I discovered Problem 2 last night after deciding to test the flash in other situations so no idea if it would have reacted the same way before the Samsung service.
Thanks in anticipation