C.Fn iv

[shiro_samarakoon]

<p>Hi,<br>

I am a armature photographer and I have a canon 450d camera. I am struggling to understand the meanings of custom function – C.Fn IV: Operations/Other. There are 4 options:<br>

0:AF/AE Lock<br>

1: AE lock /AF<br>

2: AF/AF lock, no AE lock<br>

3: AE/AF, no AE lock<br>

I read the manual and did quite a lot of googling to understand this, but not successful and it is confusing... Please expalain the meaning of these and when I should use what....<br>

Any help is much appreciated!</p>

<p> </p>

[jpk]

<p>This function gives you possibility to define what your camera should do when you press <strong>shutter release button or AE lock button</strong> (marked with asterix*). Default setting ("0")is that half pressing <strong>shutter release button</strong> activates AF, pressing <strong>AE lock button</strong> locks exposure - apreture and shutter speed.<br>

When this parameter is set to "1" half pressing <strong>shutter release button</strong> locks exposure, pressing <strong>AE lock button</strong> activates autofocus.<br>

"2"- when you press <strong>shutter release button</strong> your camera will set focus on desired object. Then you press <strong>AE lock button</strong>, and since this moment AF is locked on the distance you choose first. In this situation you are not able to lock exposure parameters in any way.<br>

"3" - <strong>shutter release button</strong> activates exposure metering, <strong>AE lock button</strong> activates autofocus. Again you are not able to lock exposure parameters in any way.<br>

Options 2 and 3 are less easy to understand, though sometimes the difference between <strong>activating</strong> and <strong>locking</strong> autofocus or exposure can be important, but so far I had absolutely no need to change this function.<br>

Regards.</p>

[tom_berkowski]

<p>I also never understood these descriptions. I finally figured out all I need to know is CF4-1 is back button focus with the * button. (I have a 5D original model.)</p>

<p>I either use CF4-1 with full manual exposure to set focus periodically when shooting mutiple shots of simlar subject, or I use CF4-0 for all other situations.</p>

<p> </p>

[shiro_samarakoon]

<p>Thanks heaps..... Appreciate your help!</p>

[mikesc]

<p>I always found that this article does a pretty good job at explaining it as well.<br>

<a href="http://learn.usa.canon.com/resources/articles/2011/backbutton_af_article.shtml">http://learn.usa.canon.com/resources/articles/2011/backbutton_af_article.shtml</a></p>