7D AF spot problem

[Tabazan]

Hello to all,


The AF spot on my 7D, event on contrasted and "clear" target, randomly point focus on other AF points than selected. 1 pictures on 2-3 are obviously out of the target (checked with DPP).


It's the second time I send it to Canon Services, and even they hard reset (or do whatever, no work done is precisely described) , the porblem continues.


Note that the 7D works perfectly well with other AF.


The 7D has been bought around 1 year ago (seems first version had this problem, but maybe it's just a myth)


Do someone has this problem ?


Thanks for your help and suggestions

[neuroanatomist]

Are you referring specifically to the Spot AF function? You're saying that you manually select an AF point (say, the center point), but then when you take the picture some other AF point is actually used, and DPP shows the other (non-center) AF point as the active one for that shot?

[HDNitehawk]

It was hard to follow what you are saying, but if I understand correctly:


You choose a single individual AF point


Then the 7D will randomly pick a diffrent point to use for focus, one that is not selected.


And even DPP will show the other focus point as the one used


And you are, or are not in Single Shot Mode?


Is that correct?


Edit: I guess I should type faster Neuro beat me to the question

[neuroanatomist]

S'ok, Rick...but you're right, the situation is a bit unclear. It sounds like the OP may haveAF Point Expansion selected, or perhapsAutomatic AF point selection (or Zone AF, which is essentially Automatic AF point selection restricted to a subset of the AF points).


My confusion is that "AF spot" can mean AF point (i.e. the little box in the viewfinder), whereas "Spot AF" is a specific AF mode on the 7D.


Or we're misunderstanding, and the issue is that the region of critical focus in the shot is not were the selected AF point is, but rather somewhere else in the frame.

[Tabazan]

Sorry it wasn't very clear (I usually speak french ... )


I select the spot AF (center point) + One Shot


In DPP, the center point is red (on the target) , but the focus is elsewhere (and not specifically on an AF point)


But ... thinking of it maybe I make a mistake in using the spot AF for action/sport pictures ...[:S]

[neuroanatomist]

But ... thinking of it maybe I make a mistake in using the spot AF for action/sport pictures ...

Canon thinks so, at any rate. Here's something [url="http://www.learn.usa.canon.com/resources/articles/2011/whats_news_eos7d_article.shtml]they say[/url] about Spot AF: "[i]By forcing AF upon only a tiny area of your subject, if that happens to fall upon a part of your subject that’s relatively plain, solid and lacking detail, the AF system may have trouble focusing upon it. [/i][i]This can be a real problem with fast moving subjects, especially if they’re moving erratically. [/i][i]At times like these, actually having a larger area can be a more effective way to shoot.[/i]"


For action pictures, you might consider AI Servo mode with AF Point Expansion or Automatic AF point selection.
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[Tabazan]

Apart from sport here are pictures sent to Canon - Swiss - tech service - CPS





Full one :

[Tabazan]

And crop.

[neuroanatomist]

What lens? What aperture? Have you done an AF microadjustment, and if so, how?

[Richard Lane]

Hi Tabazan,


If you are using One Shot for a moving object like in sports and you hold your finger down on the shutter button, then only the first picture will be in focus, even if the little red square is located perfectly on your subject. This is because One shot, will lock the focus on your subject. This works well for stationary subjects when you would like to lock focus and then recompose the shot for best compostion. However, if the subject is moving toward you or away from you, then the new subject position wont be in focus, because it already has locked on the subjects first position, and will no longer AF, even if the red square is perfectly on them.


So, as Neuro has suggested, you should be using AI Servo to focus on, and track moving subjects. In AI Servo you won