1DsmkIII

[KevinA]

I'm having problems with my 70-200mm f2:8 is. It's not doing infinity very well, it's very unsharp in fact. I admit I have not set up the micro focus but I thought that was for very fine adjustment/ tinkering, this is just  unsharp. If the object if full frame it's pin sharp, if it's a general view it's unusable. Anyone else have this problem and cured it with fine focus?

Kevin.

[KevinA]

What worries me is that sometimes the camera knows where infinity is and produces pin sharp results (Frame filling subject) It's general longish lens views that are very soft, I can't see micro adjustment solving this.

Kevin.

[Josh-H]

I'm having problems with my 70-200mm f2:8 is. It's not doing infinity very well, it's very unsharp in fact. I admit I have not set up the micro focus but I thought that was for very fine adjustment/ tinkering, this is just  unsharp. If the object if full frame it's pin sharp, if it's a general view it's unusable. Anyone else have this problem and cured it with fine focus?

Kevin.
[a href=\"index.php?act=findpost&pid=200895\"][{POST_SNAPBACK}][/a]

Are you sure the subject you are focusing on is actually far enough away to warrant 'infinity'?

Sorry if this seems obvious - but I have seen this in the past where someone says, hey my lens doesnt focus at infinity - it almost always turns out to be user error - in other words, choosing a subject to close to be using infinity. Easy to check this - focus on something you think should be infinity, then see what the auto focus does.

[KevinA]

Are you sure the subject you are focusing on is actually far enough away to warrant 'infinity'?

Sorry if this seems obvious - but I have seen this in the past where someone says, hey my lens doesnt focus at infinity - it almost always turns out to be user error - in other words, choosing a subject to close to be using infinity. Easy to check this - focus on something you think should be infinity, then see what the auto focus does.
[a href=\"index.php?act=findpost&pid=200900\"][{POST_SNAPBACK}][/a]

Oh yes, beyond any shadow.

Kevin.

[sergio]

Might be the lens bayonet. Have it checked.

[KevinA]

Might be the lens bayonet. Have it checked.
[a href=\"index.php?act=findpost&pid=200903\"][{POST_SNAPBACK}][/a]

No problem on my sMKII.  If it was not mounting properly I would expect it to be wrong 100% of the time.

Kevin.

[KevinA]

No problem on my sMKII.  If it was not mounting properly I would expect it to be wrong 100% of the time.

Kevin.
[a href=\"index.php?act=findpost&pid=200946\"][{POST_SNAPBACK}][/a]

A bit more experimentation on my part.
Switching from  manual to AF throws the image out if it's a low contrast subject the red focusing square is on.
If I line the red focusing square up on an electricity pylon against the sky the AF works fine.
Mmmm this is problem, is it just my camera or do they all work like this and is there anything in menu settings I've over looked?

Kevin.

[KevinA]

Some quick tests from my bedroom window, I did quite a few they all gave similar results.
1st file Canon focus on trees
2nd manual focus
3rd Canon focus on pylon.
They are all at the same focal length, crops might differ a bit. but it gives you the idea.

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