Posted: 6/3/2017 1:48:55 PM EDT
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I recently purchased a Canon 24-105 F4L IS. If I use live view my pictures come out sharp. If I use auto focus the pictures are hazy. It does not appear to be a calibration issue. The focus isn't shifted front or back. The whole picture is far less sharp. The camera is a 7d Mk ii. What would cause this?
Focused using live view 
Focused with auto focus 
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I'd try it again on a tripod, IS OFF, single shot, at f/4, maybe adjust the ISO so I could shoot at 1/300s. See if the differences are still there.
Mine does something similar, but only in AI Servo - image is slightly "fuzzy", or one part of the image is focused and other parts in the focal plane are slightly "fuzzy". Drives me nuts trying to get good photos of aircraft. Single shot gets me sharp images if I do my part. edit - might want to read this thread and maybe do the Dot Tune procedure just to eliminate another variable. http://www.fredmiranda.com/forum/topic/1187247/33 |
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I did dot tune and it helped a little. I really like that technique.
For another test i switched to manual mode so nothing would change and focused with live view. I then switched to manual focus and turned off live view. There is still a difference in sharpness between the two photos. I dont understand this problem. If the exposure and focus settings are exactly the same why is there a difference in sharpness between live view and shooting through the view finder? |
| I made some progress. It was partly user error. By using the dot tune technique I was able to see that auto focus was moving after getting a focus lock with live view. I can fix this with micro adjust. Right now I have the adjustments at W/9 T/10. Now the problem is that I can get autofocus to work perfectly but only at one distance. If I focus on a different object at a different distance I need slightly different numbers to keep solid focus. For example in the fire hydrant I posted I need an adjustment of 10. If I go to the backyard and focus on a steel target that I have at a little closer distance my adjustment number needs to be 12. Is this a limitation of the focus system in the camera or a problem somewhere else? |
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Here's Canon's page on microadjustment and the link to their guide. http://learn.usa.canon.com/resources/articles/2016/af-microadjustment-landing.shtml
According to Canon, in their guide they state that you should do the focus microadjustment at the distance you usually shoot, and if you can't for some reason (maybe you shoot at many different distances), do the adjustment at 50x the focal length. They also state that adjustment at distances that differ significantly (undefined) from where you made the adjustment may not give precise focus adjustment. (Page 5 of their pdf) As for me... my current tele rig is the 7DII and 100-400L II. So far in general use, I get sharp images throughout the focal lengths at distances less than infinity at 400mm when using single shot, which is fuzzy enough I want to fine tune. Once I do, performance at 400mm and infinity improves, but I loose some sharpness everywhere else. Best overall performance for general use in my case was to return adjustments to "0". An option for you (if you can't/ don't want to return the body) could be to document what your body/ lens is doing, what the results of MFA were, and call Canon. They may have you send in the combo, they might be able to adjust both as a set, and you might get you better AF performance. I haven't done this, but I have read of people doing so. Some have said it was worth it, others not so much. |
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Quoted:
Here's Canon's page on microadjustment and the link to their guide. http://learn.usa.canon.com/resources/articles/2016/af-microadjustment-landing.shtml According to Canon, in their guide they state that you should do the focus microadjustment at the distance you usually shoot, and if you can't for some reason (maybe you shoot at many different distances), do the adjustment at 50x the focal length. They also state that adjustment at distances that differ significantly (undefined) from where you made the adjustment may not give precise focus adjustment. (Page 5 of their pdf) As for me... my current tele rig is the 7DII and 100-400L II. So far in general use, I get sharp images throughout the focal lengths at distances less than infinity at 400mm when using single shot, which is fuzzy enough I want to fine tune. Once I do, performance at 400mm and infinity improves, but I loose some sharpness everywhere else. Best overall performance for general use in my case was to return adjustments to "0". An option for you (if you can't/ don't want to return the body) could be to document what your body/ lens is doing, what the results of MFA were, and call Canon. They may have you send in the combo, they might be able to adjust both as a set, and you might get you better AF performance. I haven't done this, but I have read of people doing so. Some have said it was worth it, others not so much. |
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I finally got fed up with the lens. I confirmed that it back focuses but it does it more the farther away the subject is. The neccesarry adjustment ranges from 0 to -20 depending on how far away the target is. I can only calibrate it for one distance. I called canon and i am shipping it back for them to look at. I really hope that they are able to fix it.
None of my other lenses do this. My 18-135 efs performs much better. It is almost always perfect at max focal length. |