MX300 - autofocus noise
 

If you lock down your Panasonic MX300 (and quite possibly the 350 and 500 as well) on a tripod, try this. Fit a microphone to the intelligent shoe. I used a Senheisser MKE300, but I guess any mic better than the in-built ones will do.

Listen on headphones with the camera turned on, but no tape in it and not recording. Pretty quiet, huh? Now bring your hand up in front of the lens and wow, suddenly the autofocus mechanism whirrs onto the soundtrack. Pull your hand away and hear the autofocus motor noise subside.

If you switch off the a/focus the camera remains silent, so if you're shooting with an on-camera mic in a quiet location, consider turning off the a/focus for better sound.

tom.

Thanks, Tom. I guess a good SLR adaptor and high quality directional mic will "cure" some of that, or using manual focus. However, I admit, when I'm out and about and want to capture something fast, I put the cam in auto and press the little record button. I didn't realize the auto focus made so much noise, I'll have to try that and see!

It could be a case of "acoustic reflections". Like an echo.

Is this the "doppler effect?" Can't recall, haven't been in university since 1990...

Your cam makes the whirring noises, and reflects off your hand back into the mic, so that's what's being recorded.

Without the hand, there is no reflection so the noise goes off into space, and no noise gets reflected to be recorded.


You get the same effect if you drive with your window down, and every time you pass a car, it seems "noisy" 'cos it's the engine noise reflected back at you.

Still, it's a pretty interesting phenomena.

No no - but a nice idea Steven. When I say move your hand in front of the lens I was only giving that as an example. If you slowly pan the camera on a tripod you can hear the autofocus start to work as different objects in the room cause the focus to change. If I point it out into the garden and pan the auto focus doesn't bother to switch on as everything's the same distance away.

Interesttingly the vibrating element OIS that Panasonic use is completely silent on this camera, whereas the VAP on my VX2000 makes a great deal of noise when its working.

tom.

I realised that listening to the headphones, especially unbalanced headphones, is not a good judge, because the AGC will actually kick-in and take care of low noises, etc.

I tried monitoring a shot with my $5.00 headphones and was shocked to hear VERY loud background noises, but when I playback the tape, the sound is clean and more to what the ear hears.

I am guessing that Panasonic forgot to output to the headphone the recorded sound, but rather the raw sound captured by the mic. Then again, I am only guessing.