Hi,

In April 2013 I purchased a Canon 6D with the EF 24-105mm L IS USM Lens. 

Today I was shooting looking directly down and noticed the lens zooms in while in the down positon.

This was rather frustrating as I had to keep zooming out to readjust the shot.

Is this normal? or do I have a fault lens?

I had the lens sitting at the 35 mark and it slipped to the 70 mark within 3 seconds.

Thanks