Have you seen the comparisons between 5D Mk III and the A7S ?

It's not just about the sharpness(which is a lot better in the a7s), it is too about the dynamic range and the robustness of the codec.
Sure, 650d can do ML, but that's only 720p, any higher it skips frames.
Also, what I like most at the a7s is that it's native iso is 3200, which means less light does more job. It is important to me to have a camera that will reduce my ligthing costs.
Thanks for all of your advices, all of them were very reasonable and made me think this thing through, what I've finally decided is to go with this bundle:

Sony A7s
Zeiss Loxia 50mm f2.0
Zoom H6
Rode NTG4+
and lotsa ND filters

I got this for a very reasonable price and I think it will give me a nice boost into the cinema world. Of course, I will continue using my 650D as a B camera, which is great.
I often feel the need of a second camera on shoots.

P.S.

I almost took the GH4, which I really like. But what I really love is Zeiss Glass and how it works with the Sony cameras. After all, if I made a mistake it's only for life.

Thanks again guys, this has been very helpful to me.

Cheers

Hello Lofar,

Just when I thought I'd get the a7s, you're here to change my mind. About the t3i(same sensor as t4i, t5i... ) I agree, it is sharp to a point, but nothing compared to these 2 beasts.
Considering that I already put audio in the price, and I own pretty decent ligthing.
What would you have me do? gh4 or a7s?
After your answer, it seems that I will learn much more with the gh4, than will I ever learn with the a7s. Having in mind that the gh4 is not lowlight camera will make me think for solutions and the cheap lenses for it, make it so good.

But are those lenses going to be worth it in few years? Since they're MFT mount...

P.S.

I've used both of them, and I really like them both.

I've spent many months with the t4i, and believe me when I say it's not sharp.
Also the codec is very breakable and to be honest I don't have the time for the ML workflow. Since to get usable picture from it you need to do 3-4 processes before just importing it.

I'm not buying the a7s to make Hollywood kind of movies, but to learn as much as possible when the time comes. Of course I don't plan any of these to be my last cameras, that's why I decided to stop worrying and go with the a7s. Since it's more likely that it will suit my needs now and whatever I'll need in the future.
You're right about the music video statement. But I think both will work there.

When it comes to that, when I read the specs and see the quality of the gh4 - I want to buy the gh4.
But when I see the specs and the quality of the a7s - I want to buy the a7s.
And it goes round and round.

Thanks for your brutal advice, I really liked it!
I wish more people would advise like this.

Cheers

Hey Andy,

Thank you very much for your help, I really do appreciate it.
I've chosen the a7s, mostly because of the lighting. As it seems, you can light a scene only with flashlights on high ISOs with this thing. That will help me with the cost of lighting, so I don't have to use such strong lights to light a simple scene.
I will feel like Kubrick, lighting a scene on candles. ( right? >.< )
The thing to be able to do more with less, seems so good to have.
I will hate the fact that there is no 4K, but as I said. I'm still a beginner, and the XAVC will help me learn how to color flat images without having to use a beast of a machine to do that.

I really love the GH4 colors, sharpness and it's good price, but I think the A7S will suit me better.
I'll get it with Zeiss Loxia 50mm f2.0, Zoom H6 and Rode NTG4+ for a start, and I'll go from there. Also, don't forget the APS-C option on this thing. 2 Lenses in one.

I really appreciate your help, I'm in debt to you.

Cheers

Hey Guy,

Thanks for your help. Indeed, I love the image from the Canon C100 I, also it's ND filters make it so much worth it.
The situation is a bit complicated, so I must take one of the 3 cameras.

Otherwise I'd probably be taking that with some good lens.

Sorry for the triple reply, I've no idea what happened...