Problem with Canon 7D Mark II not always focusing with Canon EF 100-400mm f/4.5-5.6L IS II USM lens.

[eji2005]

Sent both camera and lens in for repair. Got both back and within a month later it started not to focus all the time again. Anyone else having this problem?

[diverhank]

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@eji2005 wrote:

Sent both camera and lens in for repair. Got both back and within a month later it started not to focus all the time again. Anyone else having this problem?

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I think we discussed this once already...Try to set the "Lens Drive When AF Impossible" option to ON (always search).  This might be the culprit even though I have not heard this problem with this kind of lens.  I find that if you turn this to OFF, once in a while the camera wrongly thinks AF is impossible and stops trying to focus.  I have this problem with both my 5D3 and 7D2 when using the 400mm f/5.6L.  No problem if you set it to ON.

[eji2005]

I changed the "Lens drive when AF impossiable" back to on ( always search) and I'll see if that helps tomorrow. Thanks and hopefully this will work because I don't want to send it back to Canon for repair.

[ebiggs1]

This may be a double sided issue.  First incorrect settings in the camera and second user technique.  If you go outside on a bright sunny day and try to focus on an object 25 to 30 feet away, does it work?  Make sure you set the 7D to "P" mode to try this.  SIngle focus point and in One Shot.  If it works it is likely OK and you need to evaluate your shooting techniques.