24-105L focusing issues

arad85

arad85

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Andy
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So, in addition to breaking my new (to me) 5Dmk2, it appears that the lens front-focuses. The following two 100% crops show it:

Camera doing autofocus on the weed leaf (centre image)


4967013315_aa4c5eab38_z.jpg



Me doing manual focus on the weed leaf (centre image)

4967013771_408876b94e_z.jpg


If you want to have a look at them larger, they can be seen in this Flickr set
here

Anyone else with this problem? I'm 99.9% convinced it needs to be sent to Canon for calibration and it is under warranty, so no issue there.

Has anyone else seen this? Do you think it's a long way out?
 
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You need a better test subject with more contrast and no clutter infront of the subject to ensure the auto focus is focusing in the correct place.
 
It's pretty consistent whenever I take a picture... The 70-200 focussed perfectly 4 shots at 200mm on that exact leaf within 5 minutes of taking those pictures.
 
There is grass in front of the weed.
Find a better subject, then micro adjust if necessary. 5 mins, job done.
 
User Name said:
There is grass in front of the weed.
Click to expand...
But the 70-200F4 is perfect 100% of the time (4 photos were virtually identical). See:
4967801576_b91933379b_z.jpg



User Name said:
Find a better subject, then micro adjust if necessary. 5 mins, job done.
Click to expand...
It's fairly consistent. The problem with microadjustment is that the 450D doesn't have it and I'd like to be able to use the lens on both cameras.

Here is a test shot at 2.5 metres at 105mm. Taken on a tripod with mirror lockup, ISO200, F4, 1/30

4967188011_d23e8e272a_z.jpg


The focus point was dead centre on the mid vertical bar. Looks like somewhere between 2 and 3 cm forwards to me....
 
And this is what the 70-200 made of that test chart at exactly the same position (at 100mm zoom):

4967229827_2d7c0dda22_z.jpg


and at 200mm zoom:

4967230137_ee27477ddd_z.jpg


Pretty much spot on I'd say....
 
adam-gardner said:
agree, i have the 24-105 and have no issues
Click to expand...
Just because you don't have issues doesn't mean.... ;)

Have a look at the other shots posted. Most of my shots, of whatever subject (centre AF selection point selected only), come out slightly front focused.
 
Never mind, found the thread.

Here's the test shot. Focus point centred on the edge of the banana chip where it meets the bran flake in the top third left hand. The ruler intersects the front of the box at 150mm. Shot on a tripod, using mirror lockup with a remote release. I took 4 images, each time resetting the focus to infinity before autofocusing. I can't tell them apart - they're all like that.

4967409815_c5afcb8e09_z.jpg
 
No idea what banana chip you were focussing on so the last test shot doesn't mean a lot to me.

However, looking at all the rest of your shots on this thread, they all show very obvious front focussing.
 
Pic has gone. The vanishing banana chip!

Presumably it was a crop from an image at f/4 shot at a sensible distance? In which case, I think the focus was around the 50mm mark, which is quite a lot of front focus.

Cross-check with other cameras and lenses in case you need to get both camera and/or lens calibrated. It's really easy to rattle off a load of test pics once you get the hang of it. No need for mirror lock up and just take a peek on the LCD.
 
Mikesphotaes said:
No idea what banana chip you were focussing on so the last test shot doesn't mean a lot to me.
Click to expand...

Image edited to have a red dot where the central focal point was:

4967489157_df0826ee76_z.jpg



Mikesphotaes said:
However, looking at all the rest of your shots on this thread, they all show very obvious front focussing.
Click to expand...

That's what I think too :)
 
Yup. F4 from about 2.5m away. I'm 99% convinced it's the lens as the 70-200 in exactly the same position is dead on as witnessed by this shot of the 70-200 @ 100mm:

4968114138_599d0d8118_z.jpg
 
arad85 said:
Yup. F4 from about 2.5m away. I'm 99% convinced it's the lens as the 70-200 in exactly the same position is dead on as witnessed by this shot of the 70-200 @ 100mm:

<snip>
Click to expand...

Sharpest point there is around 160-170mm... :thinking:
 
HoppyUK said:
Sharpest point there is around 160-170mm... :thinking:
Click to expand...
Looking at the original, it appears to be around 160. That's the worst of the test shots though (should have looked more carefully before throwing it up). The others appear to be a lot closer...

4968175912_047f55a98d_z.jpg


and:

4968179714_0fb3de1ed3_z.jpg
 
Lens is currently at Canon being adjusted. Apparently it front focuses by around 5cm according to their (very nice) tech. who has called me a couple of times to keep me informed. He's adjusting and doing some before and after prints for me. Not bad given they only received it yesterday (but it may have been fast-tracked given it went in with the 5Dmk2 which was sent back after repair as they hadn't reconnected the microphone when they fixed it when it was there a couple of weeks ago)
 
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