Using ST-E2 as focus assist for Canon 5Dm2. How to disable firing?

[adriaan bos]

<p>Hi there,</p>

<p>I am trying to use the Canon ST-E2 infrared transmitter as a focus assist for the Canon 5D m2.<br>

But I don't see the option on the camera to actually disable the flash from firing? Now it seems to expect the flash to fire and it create an underexposed picture. I remember on the 20D there was a custom setting that could stop the flash from firing, so turning the ST-E2 on or off had no effect on the exposure.<br>

Am I missing something here? Is there still a way to stop the flash from firing, while still using the infrared pattern from the ST-E2 for better focussing?<br>

Thanks!<br>

Adriaan</p>

[scott_ferris]

<p>I'm sorry I don't understand. What flash? There isn't one on the ST-E2 or the 5D MkII. On my camera, not a 5D MkII, I just put it on and it works, no under exposure.</p>

[PuppyDigs]

<p>As I recall, most EOS without a popup lack the CF to disable flash firing while enabling AF assist. Yep, even the lowly Elan 7 had that CF. You need to buy a 50D or 7D if you need that feature. Unfortunately the ST-E2 lacks it's own CF so you the workaround is kinda crude. The camera thinks the ST-E2 will fire a Speedlite so it screws up the ambient exposure, although the amount varies with brightness. I used the ST-E2 with my 5D and 5DII a lot. Sometimes I achieve AF with the ST-E2, turn it off, switch to MF, and take the picture. Of course I'm using a tripod so it's no biggie.</p>

<p>The underexposure of the ambient while using flash is called by NEVEC. It's supposed to be a feature and not a defect. I think if you switch flash metering to "average" both NEVEC and auto FEC are defeated.</p>

<p>http://eosdoc.com/manuals/?q=NEVEC</p>

[scott_ferris]

<p>Well, you learn something every day! I have read that article before as well! DOH! Thanks, Puppy.</p>

[kenny_c]

<p>I dont get it, if you are on manual, how does it affect exposure?</p>

[PuppyDigs]

<blockquote>

<p>I dont get it, if you are on manual, how does it affect exposure?</p>

</blockquote>

<p>Ot only effects exposure if you rely on the meter reading. You can set exposure any way you want. I normally use it in M mode and, depending on the camera, some suffer reduced ambient exposure in M mode while others don't. So I meter in M with the ST-E2 off, and then lock AF with the ST-E2 on, and ignore the meter scale. Not rocket science but a pain in the arse.</p>

[adriaan bos]

<p>I would simply want to improve focus in dark circumstances, any other tricks I could use?<br>

I did see that it might help covering the contacts, all but the large middle one?</p>

[adriaan bos]

<p>Just to be complete, got the problem solved.<br>

In the menus of the 5Dm2 there is an External Speedlite Control - Flash function settings. It only shows up when a flash is connected and ON.<br>

In it you can disable the flash. This stops it from firing and also from affecting the automatic exposure setting. But it still uses the red raster helping with focus... so great.</p>

<p> </p>