Defeating the AGC on the 7D, controllable sound directly to the camera

So this is a video I just shot for my wife's company at this year's infoComm trade show held in Las Vegas, NV. I had 20 of these types of videos to shoot in one day so they had to be short, not too complicated and easy for me to edit. Yes, I could have used my Tascam DR-100 to record the audio and probably had better control and better sound, but I didn't have too much time to spend in the edit. Syncing the sound isn't hard, but it is time consuming and I don't have Plural Eyes. I also didn't have a lot of help shclepping stuff and wanted to be fairly compact. I did this job on the cheap, more as a favor for a really nice guy. So I wanted to lower the time I'd have to spend on each video in the edit.

Knowing about the AGC and the lack of Magic Lantern software available for the 7D I found a solution, but it requires that you only get one usable track of audio. The other is basically thrown out.

So here's my set up: 7D with 24-70L on my rail system with follow focus mounted on my tripod with fluid head. Hanging off the rail system and back of the tripod is my Sound Devices MixPre, 2 channel mixer in it's Porta Brace bag. Channel one of the mixer has a Lectrosonics 201 wireless system feeding it and channel 2 has a stereo mini to XLR connected to the headphone out of my HTC Amaze 4G cell phone. I recorded 12:30 of 1K tone as a mp3 file and transfered it to the music player in my phone. Before I started to roll the camera I would start the tone from my phone and feed channel 2. I adjusted the output gain via the mixer to +3 dB and adjusted the gain of the wireless system to hit just under 0dB on the mixer. The output of the mixer is a line level feed so I have a pair of 40dB pads to lower the line lever signal to a mic level which is then fed to the camera via a Y cable with a pair of XLRs into a single stereo mini connector. The result isn't perfect, but for a camera that you can't over ride the AGC, this is pretty much what you have to do. In all my tests prior to actually doing the job, it worked perfectly each and every time. So I did the job with my 7D as opposed to using my old Sony PDX-10 camcorder that I knew would work, but wouldn't look as good.

I also had a small, 160 LED Neewer CN-160, battery power light on a stand to help fill in the eyes or light up a persons upper torso in the darker booths. It helped a lot as the show floor lighting is really horrid and some of the rooms or booths were really dark.

Here's the result of one of the first videos I shot that day:

https://vimeo.com/4413​9292

ChasWG wrote in post #14585728
Here's the result of one of the first videos I shot that day: https://vimeo.com/4413​9292

Pretty good video overall, a tad bit orangeish, but over all good.

That stated I’ll give you a tip if you shoot one of these again, when working with people who are not trained to be on camera (which I can only assume by the way he presented himself, the rep in the video isn’t) and you see the “crotch covered” cut, stop shooting and then hand the person being taped a piece of paper, a product brochure or anything to keep his weak hand busy forcing him to use his strong hand to point out features of the product and to help prevent hand switching and hopefully to keep either hand clear of the “C” zone.

Also the product being demonstrated should always be placed on the strong handed side of the person doing the demo so that they do not cross their chest when pointing out features of the product.

Generally speaking with product demos chest crossing should be avoided if at all possible, as it is an authoritative not informative gesture, cops cross their chest when asking if you put that car in the ditch, whereas instructors will raise their hands away from their body when trying to move attention from them to the subject on the board behind them.

It’s purely psychological, but it has been proven to have a measurable effect on the how a video is perceived.

Wayne

Thanks Wayne. The lighting is what the light was going to be. Convention show floors are always a disaster trying to get a good white balance with that many different light sources. Maybe I could correct that a bit in post though.

As for the "talent," that I had no control over. This was set up by my wife's boss and each manufacture. I also had only 30 minutes to set up, shoot and get cut aways and then travel across the floor to the next location to set up and do it again. No breaks in between. All as a one-man-band. The whole time being driven by a guy that has no idea what it takes to do this kind of thing. I had to do that particular video twice as I accidentally knocked the plug out of my cell phone feeding the tone to the mixer. Thus allowing the AGC to ruin the other channel of audio. Of course my wife's boss was trying to say that we didn't need to redo it and that it was fine. Ummm... NO! So I did it again despite what I was being told.

Over all I think the videos got a lot better as the day went on. I still had to keep up a run-like pace, but my wife's boss let me get more creative with the shots.

Thanks for the suggestions about the video, but this thread wasn't really about the video, but more about getting the audio onto the 7D and past the AGC.

By the way, what did you think of that Vaddio product? I know you would be able to appriciate that above most others here.

ChasWG wrote in post #14588155
Thanks Wayne. The lighting is what the light was going to be. Convention show floors are always a disaster trying to get a good white balance with that many different light sources. Maybe I could correct that a bit in post though.

Mixed lighting is always a pain in the butt, but you did nicely and as for correcting in post you already mentioned being on a short timeline and there is nothing like adding a few corrections in post to bring the rendering to a snails pace.

In my opinion you where brought into the mix because you where trusted to get the job done with a mix of the correct equipment and the skills to fly that plane, as such you are in a plum position to “recommend” minor and quick changes and those changes if presented properly will raise your stature and will make the difference between a good video and an excellent video.

Now I was not there and cannot judge what happened, but I have done many shoots in similar situations and have learned that guy, be he the boss or just writing the check, will have an idea of what he wants but no clue as how to execute it and that is where you with your family of skills steps in and saves the day.

Welcome to my world.

Now if you used a tripod and are going to do this again consider getting a dolly such as a Manfrotto 114, being able to set up the tripod, camera and accessories then being able to roll the entire assembly from one interview to the next is very time saving.

Those types are commonly known as assignment managers or news directors.

Very good, because if you didn’t re-shoot the clip there is a good chance your wife’s boss would have forgotten about telling you not to redo it and then blame you and by proxy your wife for the crappy audio. Boss’s can have some really selective memories.

Maybe the next time the boss will make life easier on the both of you and just leave you alone to do your job.

Like this?

http://www.sescom.com/​product.asp?item=DSLR-AGCY

It looks like some high end corporate/educational video gear, I could see it being used for both security and video conferencing / learning purposes, those Sony EVID70 are amazing industrial PTZ cameras.

Wayne

Yeah, I knew about that Sescom cable, but my gear starts with XLRs and I wanted to run it all through my MixPre mixer, so that cable, would be nice to have, but not needed in my case. And even with that cable there is still no way to adjust levels without using a mixer.

It looks like a quality cable though and something anyone with a 7D probably should have if they want to record external audio to the camera.

As for the Vaddio stuff. Yeah, I'm sure you're spot on. Just under broadcast quality. Nice stuff, but not the absolute best out there.

I looked at my video again. Yeah it was orange, but most of that was that wild orange carpet and back ground they had at the show. Remember, this was in Vegas!

Hi,
This a a bit off topic, but 7D is getting new firmware:

http://www.dpreview.co​m …-firmware-v2-major-update

and then this blurb (does this mean the AGC can be defeated?)

"Improved audio functionality in movie mode also provides aspiring videographers with greater control while shooting videos. Users can complement the camera's Full HD (1920x1080p) movie footage with 16-bit digital stereo sound, sampled at broadcastquality 48KHz, and new manual control of audio levels allows users to choose from 64 sound levels. A digital wind-cut filter also reduces noise made by movement of air around the microphone, ensuring sound is clear and free from peripheral interference."

^^^^^^ Yea thats what I was going to (Jokingly) suggest! Just wait till August and it looks like the 7D will have the same audio features as the 5D2. No more defeating the AGC!