Black Spot when lens is stopped down

I have a brand new BMCC MFT camera, and when I took it out shooting with my sigma 18-35, whenever I stopped down a black dot near the center left of the image appeared. At first I thought it was the LCD monitor, but the footage had the dot burned in. Then I thought it was the lens, but when I switched to my zeiss 28mm it had the same dot in the same place. There is no debris on the sensor or front or rear glass elements of the lenses. What is the issue?!

I have a brand new BMCC MFT camera, and when I took it out shooting with my sigma 18-35, whenever I stopped down a black dot near the center left of the image appeared. At first I thought it was the LCD monitor, but the footage had the dot burned in. Then I thought it was the lens, but when I switched to my zeiss 28mm it had the same dot in the same place. There is no debris on the sensor or front or rear glass elements of the lenses. What is the issue?!

looks like dust on the sensor, blow it off with a pear blower and check that out.

Try filming a white wall, defocussing as far as possible. Still see that spot? Then it's dust (or any other smuther) on your sensor.

Try filming a white wall, defocussing as far as possible. Still see that spot? Then it's dust (or any other smuther) on your sensor.

I did and the spot is still there, however the sensor is completely spotless. Ive taken tons on non chemical dustoff spray and its still there. I have no idea what to do.

Try filming a white wall, defocussing as far as possible. Still see that spot? Then it's dust (or any other smuther) on your sensor.

I did and the spot is still there, however the sensor is completely spotless. Ive taken tons on non chemical dustoff spray and its still there. I have no idea what to do.

unluckily you got a false sensor

Call BMD asap. if you're sure the dust is really there and you can't get it off.