7d will not auto-focus after auto power off

[eric_bradley]

<p >I’ve had a 7d now for over two months and whilst I am generally very happy with it, and have had excellent results with the auto-focus on such things as birds in flight, I have a specific problem which I haven’t seen reported anywhere. Basically, sometimes the camera will refuse to focus. I don’t mean that it will try to focus, hunt and fail, it just will not make the slightest attempt to focus. As far as I have been able to tell this typically seems to happen after the camera has automatically powered off due to inactivity and I am activating focus with the shutter release. This is very frustrating and I have missed quite a few wildlife shots because of this. A manual twist of the focusing ring seems to kick the auto-focus back into life, after which it is absolutely fine. However, sometimes I’ve got the hood reverse mounted on the lens (over the focusing ring) and then I really do miss the shot as I have to remove the hood before I can activate manual focus.</p>

<p > </p>

<p >I am not talking here about the custom functions that change the way that auto-focus works, many of which I have set for action photography when I am in Servo-AF; this is about the fact that it doesn’t even attempt to auto-focus. I have had the same problem on several lenses, all Canon Ls. I’ve checked the contacts are clean, the auto-focus switch is set to on, there is no focus limiter set, the subject is greater than the minimum focusing distance for the lens and I am not shooting with converters to go above f5.6. I am typically shooting on these occasions in 1-shot AF. I was shooting with spot auto-focus and thought that maybe there was sometimes not enough contrast in a small area but I have had the same problem in other focus modes. Unfortunately, I have not been able to reproduce this effect at will: it only seems to happen when I don’t want it to, but it does happen at least once or twice a day when I am using the camera.</p>

<p > </p>

<p >It doesn’t seem to me like an auto-focus issue per se, more that the camera is not fully activating after being shut off (thought the display settings are all fine). I was expecting to see a firmware release by now that addressed this but now I am starting to think it must just be me (or my camera, of course!). I am on 1.1.0 btw.</p>

<p > </p>

<p >Has anyone else seen behaviour like this? Does anyone have any other suggestions I can try?</p>

<p > </p>

<p >Thanks</p>

[amol]

<p>Eric,<br /> <em>"A manual twist of the focusing ring seems to kick the auto-focus back into life"</em> <br /> <em><br /> </em></p>

<p>Sounds like a lens issue. But you mention several lenses, so probably a body issue. What lenses are you using?</p>

[keith reeder]

<p>Eric,</p>

<p>what setting do you have CFn III-4 on?</p>

[eric_bradley]

<p>Thanks for your replies. I'm pretty sure it's not the lens as a) several of them exhibit the same problem and b) they have all performed without issue on my 20D and 40D (and beloved EOS 3 before that). Lenses that I know have exhibited the problem are 24-105, 135 F2, 100-400 and 400DO. As for setting III-4, I have that set to 1 - Focus Search Off. Now that I refer to the manual, I wonder if I should try setting that to 0? I didn't think it would be that as it doesn't even try to focus and I assumed that this setting would stop the lens hunting after having tried once. Also, when AF does kick in (after a manual twist of the AF ring), it usually does find focus straight away. I suppose, however, that I might actually be putting it more in focus at this point. Anyway, I will set this CF to 0 and see if I still get the problem.</p>

[keith reeder]

<p>Does <a href="http://www.fredmiranda.com/forum/topic/855027/0#7996376">this</a> sound familiar, Eric?</p>

 

<blockquote>

<p>If you are focused on something far away and then point at something close (or vise versa) then the view is so out of focus that <em>the AF sensor cannot see anything and it won't even try to focus. </em></p>

<p>Turning this off is less important if you have USM and a focus limiter switch. One of the lenses that I use a lot has the old non-USM focus system and no focus limiter and for that I absolutely have to turn AF search off. <em><br /> </em></p>

</blockquote>

<p> </p>

[hawkman]

<p>I have also seen this when CfnIII-4 is set to off, the camera will not attempt to search in extreme defocus cases, either rotate the MF ring a bit or set this function to ON.</p>

<p> </p>

[eric_bradley]

<p>Well, that does sound familiar. I set the CFn to stop the lens going too out of focus but it appears that I may have stopped it going into focus, which is not quite what I intended! I didn't think it was a close focus/far focus issue but after this discussion, I don't really see what else it can be. As I said, I have now set this to ON but I won't be doing any photography until the weekend so it will be a few more days before I can say that this is definitely the solution. Thanks again for your help.</p>

[michael_thompson_jr.]

<p>This just started today for me. The autofocus makes just the slightest sound when I try to start it. I also got my first Err 30 in the same session. Lastly, I've had to pull the battery just to turn it back on a couple of times tonight. The on/off switch literally did nothing. I'm almost positive that all of the above happened when waking the camera up from an Auto-Off power down. What's worse is that I sent my 5DMkII to Canon last Monday for a thorough sensor cleaning and it's with FedEx for delivery back to me on Tuesday. What sucks is I have a baby shoot tomorrow morning and the 7D is my back-up. Problem is not lens specific - did it on my 24-70L and 100mm Macro 2.8L IS. Regardless, I'm pretty pissed.</p>

[desi_cresnet]

<p>Folks -<br /> I bought the camera, EOS-7D two weeks back, an upgrade from EOS-20D. I tried using with my 50mm, 24-105mm,L IS, 70-200 2.4 IS L lens. With any of these lens camera is hunting for auto focus. Is there any setting I have to look for? some sites mentioning about lens calibration (http://www.northlight-images.co.uk/article_pages/cameras/1ds3_af_micoadjustment.html) which I am not familiar with it before. Do I have to do this? OR is this some issues with camera and return it to Amazon?<br /> Not related to this issue : a sample from last night from midwest fog:<img src="http://farm3.static.flickr.com/2710/4281899315_618d14a844_o.jpg" alt="" width="1024" height="683" /></p>