Finally! Voigtlander announced the development of their 10.5mm back in September of 2014 with very little information. Now we have a ship date of June, 2015 and a price of approximately $1,149. Duclos Lenses is taking pre-orders for the lens which it will offer with their Cine-Mod for a price of $1,349. I’ve not yet been able to test the quality of this new ultra-wide prime, but if the other lenses in the Nokton line are any indication, I think we’ll all be very happy to finally have an ultra-wide, ultra-fast prime lens with proper manual controls. 
The new 10.5mm will be an excellent choice for Micro 4/3 shooters with a Blackmagic or GH4 attempting to combat the drop factor. 10.5mm will provide a field of view equivalent of approximately 21mm, depending on the specific camera you’re using. Pre-Order this new lens soon as I’m sure there will be short supply.
By “drop factor” I presume you mean “crop factor”.