Hi...I'm an amateur videographer and I recently purchased the Panasonic Lumix GH3 after researching many cameras for video quality - this camera was highly rated. However, I notice the video flickers - dim to light very rapidly when zooming in and out in all video file formats. I sent the camera to Panasonic Canada's repair outlet in Burlington, Ontario. The problem was confirmed by the repair shop and Panasonic sent this reply to them. Here is the forwarded reply to me from the repair technician:

     Good morning Wayne,

I have been advised to inform you the camera and lens are operating to factory specifications. These are characteristics of this series of cameras. This camera cannot be compared to a normal video camera. The factory explanation is below. The camera will be returned to you as we received it. I apologize that I could not have been of better assistance.

“We do not know any recording condition, but, from motion picture we suspect that it seems that it is normal performance of this unit (within specification).

Basically, the collecting amount of light changes depending up on the Zoom position.

In case of H-FS1442A, Aperture Range F3.5 (Wide) - F5.6 (Tele).

When recording the motion picture with P mode, the unit try to maintain fixing aperture.

When Zooming the lens, brightness is changes after passing concerned level of aperture.

In case of single lens cameras, aperture changes not "linear" but "step by step", although at switching point it is compensate using shutter speed and ISO sensitivities, exposure might be change.

(Just for your reference, for movie/Camcorder, since lens and Camcorder is one package, aperture is able to control linearly, exposure is not changed even if Zoom condition changes.) “

Any assistance with this issue or how I can manage it beter will be greatly appreciated. Thank You Wayne