Buying decision (I'm really stuck.)

[Aquamaria]

I'm working as an editor and got a 7D from my company some months ago. (I had a 350D before - for seven years.) Long story short, I really got into shooting videos.

 

Here's the problem: I got a 7D and some lenses (which I own, not the company) like the 50mm 1.4, 35mm 2.0 IS, 24-105 4.0L IS but I would like to do some more low/available light shooting. The 50mm would be great for this, but the 1.6x crop pretty much kills it (for me). And the 35mm is a full stop worse and not sufficient for the scenes I tried.(Actually, I need a quite high ISO with the 50mm, too.)

 

So I was looking for solutions. The 5DIII would be an obivous one, but I don't need two still cameras. (I can't sell the 7D.) I came across the BMPCC and the metabones speedbooster. I would already have bought the BMPCC, but then I also need new lenses, as there is no EF speedbooster (...yet). I'm thinking about a combining the BMPCC with the Voigtländer Nokton 17.5 0.95. Or buying the speedbooster and getting some old Nikon lenses or the Sigma 18-35mm 1.8, or... There a so many options, I simply don't know what to do. I read so many reviews, watched so many videos.

 

On EOSHD the latest article says "The low light capabilities at F0.74 and ISO 1600 are really quite unexpected. Here it resolves more than the human eye in pitch black darkness. The low light abilities of the Canon C300 and Sony FS100 were big attractions to me and I thought I’d be sacrificing this going to the Pocket. Not so!". What does this mean? Is it actually better than the 5DIII?

 

Which camera should I buy for the "best low-light experience"? The 5DIII and use my existing lenses? The BMPCC and get new lenses (which?)? From a technical aspect, I like the BMPCC more (I know it has some quirks), because I feel a bit unconformable using ML on the 5D, which is, after all, a hack.