I am pretty sure the XF300 can only shoot in varieties of HD - its minimum recording quality is 25mbs 720 up to full hd 50mbs.
Unless the US spec ones are different (I am in Pal land)
Transcoding to ProRes should not introduce any additional noise. I have used footage from these cameras a few times and found the quality to be good.
Which ProRes codec are you using ? I would usually use 422 or even HQ with 10 bit 4:2:2 files.
L&T wont change the frame size so what size are your imported clips ?
That should tell you if they are full HD or not.
If they are not you may be introducing some quality loss if you are editing them into an HD timeline.
Noise certainly is associated with low light so that is possible.
best wishes
Neil
http://www.patience.tv
