user10807: I am trying to take video for a time lapse of stuff I write on white paper. Issue is that when the paper is blank, it looses its focus automatically. Unitl something or some writing/drawing/object is put on the paper the focus will wander off. 
All this happens even when my camera is in manual mode.
Here is a sample:



First I want to understand why it happens, and, how to avoid it. I own a canon powershot sx 520 hs

user17724: It looks like by default, that camera fine-tunes the focus (even in manual focus).
From the Canon support page: To deactivate automatic focus fine-tuning when the shutter button is pressed halfway, choose  -> [  ] tab -> [Safety MF] ->[Off].

10807: <p>I am trying to take video for a time lapse of stuff I write on white paper. Issue is that when the paper is blank, it looses its focus automatically. Unitl something or some writing/drawing/object is put on the paper the focus will wander off. </p>

<p>All this happens even when my camera is in manual mode.</p>

<p>Here is a sample:</p>

<p><div class="youtube-embed"><div>
                <iframe width="640px" height="395px" src="https://www.youtube.com/embed/QqyjdMVa7g4?start=0"></iframe>
            </div></div></p>

<p>First I want to understand why it happens, and, how to avoid it. I own a <a href="http://www.amazon.in/Canon-Powershot-SX520-Optical-Powerbank/dp/B00M0QVTOS" rel="nofollow noreferrer">canon powershot sx 520 hs</a></p>
 17724: <p>It looks like by default, that camera fine-tunes the focus (even in manual focus).</p>

<p>From the <a href="http://support-asia.canon-asia.com/contents/ASIA/EN/8202125600.html" rel="nofollow noreferrer">Canon support page</a>: To deactivate automatic focus fine-tuning when the shutter button is pressed halfway, choose  -> [ <a href="https://i.stack.imgur.com/wTfaW.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/wTfaW.png" alt="Camera icon"></a> ] tab -> [Safety MF] ->[Off].</p>
