S3 intervalometer: how to fix focus?

I have dusted off my trusted S3 for some time lapse shots but cannot figure out how to fix the focus and to keep the lens from moving and trying to refocus for each shot. I have tried by setting the focus manually (MF button and up/down arrow) just before taking the first shot, but still the lens tries to refocus for the subsequent shots.

If anyone can tell me how to do that I would greatly appreciate it because my lens extension isn't smooth anymore and particularly noisy. Thanks.
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D5000 - Nikkor AF-S DX 18-105mm F/3.5-5.6G ED VR - Nikkor AF-S 50mm f/1.4 G - Nikkor AF-S 70-300mm VR - Canon PowerShot S95 - Canon PowerShot S3