Two hard to translate strings

[Alexander Shopov <al_shopov yahoo com>]

Hi guys,
I am updating F-Spot's Bulgarian translation currently. There are two strings that are hard for me to translate:
Planar Configuration
Gain Control
Can someone explain them? I will gladly commit translation comments afterwards in the source.
Is planar out this: http://en.wikipedia.org/wiki/Zeiss_Planar

Kind regards:
al_shopov