So a mark/blotch has appeared on my videos recently! I think it happened after a lens change and there was some dust/dirt on the sensor as well which was visible with a loupe. However the mark in question doesn't seem to be visible when looking at the sensor?! It is present when using different lenses/no lens even It moves in ex-tele mode (to a position which would seem to correlate with the sensor crop of that mode) If I shoot a scene which has an over exposed section it will disappear as I move the camera to place the mark onto the over exposed area- i.e. no present when over exposed

I have tried a blower to remove the dust and also swabbed the sensor with a cleaning kit which removed all the dust etc. but this mark remains!!!

So what does it look like to you and has anyone encountered something similar?

Thanks in advance all!