Magic Lantern can be downloaded from HERE
So, let's move on.
The first tab is AUDIO.
The Canon cameras, aside from the T3i (and possibly the T4i) have automatic gain control. What this means is that the camera will automatically adjust the gain (input volume) automatically. This will result in quiet scenes developing a lot of noise (hiss) as the camera ramps up the gain in an attempt to capture the sound of the scene. Since the T3i has manual gain control, and Magic Lantern manipulates the automatic functioning - you won't see this menu.
Analog Gain
This setting allows you to control your input volume manually. Figuring out the optimum settings for your rig may take some tweaking. The way you do this is set the gain at one level... then run the scene with the camera in place... watch your VU meter (that is the meter at the top of the screen while Magic Lantern is running). Adjust your Analog Gain till to the point where your meters register well and stay completely in the green... if it gets any higher, you will have to deal with clipping... This applies to all sound levels - whether using a mic, a preamp or just the microphone on the camera for reverence audio.
If you are are using a pre-amp, start in the lower numbers (probably into the negative gain) because the pre-amp boosts the audio signal already and is much more likely to clip your audio.
If you are using an external mic, (depending on the mic you have chosen) you will probably need to bring up the audio levels to get a consistent feed.
L-DigitalGain and R-DigitalGain
This is an "artificial gain" applied to each channel (left and right)...Basically, if you have a need to center the sound on your shoot, but the actors are off center of the mic, this allows you to adjust. I recommend leaving this at 0. These changes, being digital, will increase processor load, heat the camera and drain battery... Also, if your Analog Gain has been set properly, this is something that can easily be adjusted in post.
Input Source
Input source should be self explanatory. This allows you to select a specific input scheme.
Internal mic: This is the built in mic on your camera. This, unless you have no other choice, should be your last option.
L:int R:ext:I've not used this option... it seems odd to me... but it assigns the on-board mic to the left channel of your audio and uses an external mic as the right channel.
External Stereo: Select this setting if you have a mic that has a 3.5mm stero jack on it, like the R0DE Videomic.
L:int R:balanced: This is another mixed set up. It allows you to use a XLR mic with a Canon DSLR. There are adapter cables out there that make this easy.
Auto int/ext: Your camera will detect if a mic is attached automatically.
Wind Filter
This turns on a digital wind filter for the mic. This is a high pass filter. (It turns filters all the frequencies below a certain cut-off and allows frequencies higher than this line.) It can make a windy day a decent shoot day.
Mic Power
If you don't need to use this... don't. It adjust power and impedance on the mic circuit. If you don't need to mess with this, don't. If you are using an external mic that seems to not be working, try changing the setting, but this is only for the technical minded users... the manual of Magic Lantern states.
"This is required for internal mic and certain types of external mics, but it reduces input impedance. See AK4646 datasheet p.31 and the Mic power control thread.
ON: input impedance is 2 kOhm;
OFF: input impedance is 30 kOhm.
This setting is always ON when input source is either internal mic or L:int R:ext."
AGC
This stands for Automatic Gain Control. We discussed AGC at the beginning of this post... KEEP IT OFF... AGC will make your sound completely unusable.
Headphone Mon.
I know, I know... I am skipping one... but that one applies to this entry, so I am covering this now... Magic Lantern allows you to wire up a headphone cable and use the SD output on the Camera. This sounds like a small thing... but this allows you to monitor audio coming off the camera... and THAT is big...
If you plan on using a standard definition monitor, disable this. This is not available on the T3i or T4i.
If you want to use this function, look on line for the Sescom dedicated Canon Monitor cable.
Output volume
This adjusts the volume to the headphones that you are using with the cable described above. It is recommended that you use a low impedance set of headphones... higher impedance sets may require the use of a head phone amp.
Audio Meters
This enables and disables a VU (Voice Unit) meter that allows you to see audio levels as you are recording. Make sure they don't peg out and stay in the green to get good, clean, non-clipped sound.
That completes the audio menu... I hope this helps... NEXT: Exposure.
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