want to learn the video side of things for weddings.

as a pro in the stills part, I feel like a reborn amateur wanting to learn to do video for weddings.

I have the base of the stills so understanding shouldnt be an issue. its just certain rules for video that stills doenst have. like frame rate and what lenses, focusing which is manual (I use af only) and the biggest issue is looking at video and not understanding a good shot from a bad shot. meaning, the mindset of a videographer is different than a stills photographer. so there may be certain angle or shot that will be great stills wise, but not video and vice versa.
my biggest problem is understanding bit rate, frame rate and the necessary investment I need. I have a D3 and D600 but need another camera since the D3 is lazy and doesnt want to do video. one side of me says get the D7100 and the other says stick with FF and get another d600, but another more greedy side says get the d800 which is really great video quality. the D7100 is the cheapest option camera wise, but having to get lenses for w/a like the tokina 11-16 doesnt make sense. better just stay with FF and the money I save by buying DX lenses, I can add to get the D800. im still not 100% locked yet.

I saw this video
Review: Is the Nikon D600 a movie camera? - YouTube

he says the video is good, but tons of moire/AA and I dont know the level one needs for weddings. I saw edited clips and havent noticed the M/AA issues but yet I cant "see" like a videographer. I see like a stills photog. im all over the place and obviously confused. not looking to jump into it so quickly. my goal is to offer my service in about 6 months from now. there is a huge demand for dslr videographers. I have very high integrity and wouldnt jump into doing it so quickly without enough practice and proper gear and understanding it well.

some direction even for something specific I asked about would be helpful. you dont need to address all the things I mentioned.

from weddings I shot since may, videographers I saw were mostly using DX (all were canon users) D60's mainly. 1 specific uses a 5D-MIII and a D60 he uses on a tripod in a WA shot at the chuppa for backaup and a different angle. and he uses the FF 5DM3 on a monopod. another videographer uses a D60 as a 2nd camera as well, but uses A canon C100. lenses I saw they use were the tokina 11-16/16-35 II L/35 sigma ART/70-200 IS2/ zeiss 50 1.4 (the list is what they own on the whole and not one videographer has it all) and thats about it. no one had a 24-70 midrange zoom (if I recall correctly-cant remember)

but all of them except the 35mm(dont know if its a must) and I do want to upgrade my meh tamron 17-35 pretty soon. man I hate wa zooms. jeez they are horrible.

Ok so for video the D800 is king in my opinion. The D610 would be fine as well. For video you need a basic video rig and that's about a $1000 investment for a basic one. You'll need an external stereo mic as well (around $300). You might also consider an external recording device ($200-400) if you are going to do it professionally rather than rely on the camera doing the recording. You could also go with a grip to steady the camera instead of getting a vid rig, and there are small ones starting around $150-200, but better ones for more. I think one of those would be essential for mobile shots. The lens choice is going to be a fixed aperture zoom because you do not want exposure changing when you zoom. A good standard would be the 24-70mm f2.8 which is pro quality. Videographers also use primes for that reason of needing the aperture fixed. A variable ND filter is also important so you can keep the aperture fixed while changing exposure time. The top quality ones run around $100 on Ebay.

Frame rate is usually 30 fps. For that motion picture look you can use 24 fps. Bit rate would refer to the amount of digital information the sensor would be sending to an external video source. So you could use an external recorder with larger monitor if you want as well, but that is more for cinematography than weddings.

DSLR sensors are much bigger than the simple HD vid resolution, so one would think that using a DX camera is enough. But, there is also the quality of the sensor including things like high ISO noise, and most importantly the dynamic range. When you shoot vid you want to keep the camera settings as neutral as possible with no corrections to the image like NR, etc.. Then in post-production you are able to apply the correct levels to bring out color, intensity, detail in shadows, etc.. Something like a D800 is good because the sensor itself has a very high dynamic range and excellent low light, high ISO quality as well. It also can send out raw, unprocessed video to an external recorder. DX cameras don't do that, as they will be applying some kind of compression to the video.

Anyway that's about all for now.