October 24, 2014, 06:00:40 AM

Author Topic: Focusing Problem with 600mm f/4.0L IS II with 1.4X Extender  (Read 3621 times)

East Wind Photography

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Re: Focusing Problem with 600mm f/4.0L IS II with 1.4X Extender
« Reply #15 on: February 14, 2013, 10:02:05 PM »
I believe overall the AFMA is off.  The multiple catch eye could be due to the heat currents or perhaps the lens stabilizing to temperature changes.  Best results are when the lens reaches a uniform temperature.  Takes about 30 minutes to an hour for the optics to stabilize.

To all,

Thanks for your suggestions.  I'll redo the AFMA, perhaps something similar to neuro's.  At this time, I have it set to 0 which is pretty close to the original calculation from FoCal of -1.  Is it possible to set the AFMA through Canon's software?  It would be ideal to be able to do this as any touching of the camera during the calibration process is going effect the results (i.e. slight changes in distance to target).

I have used the lens/camera assembly attached to a Gitzo GT5541LS/Wimberley Gimbal Tripod Head II in manual focus.  I tried LiveView at 10X, but touching the focus ring resulted in too much movement.  4X seems to work pretty good though.  What experiences have you all had at an 840mm focal length?  The manual focusing results were not as sharp as I would expect from this lens; however, they are better than what I'm getting with AF.

I'm not sure if the problem was heat currents.  Towards the end, the cabin of the truck had pretty much acclimated to the outside temperature; nevertheless, I'll keep this in mind the next time I go out.

I'm still a little concerned about the multiple catch-eye signatures in the second photo.  Individually, they are tack sharp.  There's no way I can move fast enough (i.e. operator error) in a 1/3200 second of exposure to produce five or more catch-eyes on the target.  It's a very strange, but interesting phenomenon.

Wade

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Re: Focusing Problem with 600mm f/4.0L IS II with 1.4X Extender
« Reply #15 on: February 14, 2013, 10:02:05 PM »

revup67

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Re: Focusing Problem with 600mm f/4.0L IS II with 1.4X Extender
« Reply #16 on: February 17, 2013, 11:46:16 PM »
Wade..in calling Canon only yesterday and with a mere 5.6 L 400mm I had a difficult time focusing on a bird.  In speaking with canon that asked I checked the outside temps which were within normal range at 79° F, check the limiter either on this lens 3.5m or 8.5m and I was a good 30 feet away so either was OK (not sure what limiters if any are on the 600mm), made sure AI servo was off and on One Shot with single AF point (not the one used for Macro - saw your disclaimer that you had checked this.  It boiled down to there was not enough contrast that causes my lens not to focus properly.  Ultimately I wound up doing a manual focus.  I think you hit all the right steps but did you include the calculated MFD with the extender attached ?  I didn't see any notes on the eagle as to how far away your were and if you met the MFD total of lens and XTDr combined.

Neuro thanks for the fabulous breakdown on your use of Focal..excellent.  I have found all my shots on all 9 lenses are razor sharp now with Focal but as you say you need excellent lighting or don't waste your time and no vibration..stable flooring is key.
Thanks
Rev
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wearle

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Re: Focusing Problem with 600mm f/4.0L IS II with 1.4X Extender
« Reply #17 on: May 03, 2013, 04:07:24 PM »
To all,

Thanks for all your suggestions.  After going through extensive testing, I felt it had to be a problem with the lens itself so I sent it to Canon in late April.  It was returned early last week, and the difference is phenomenal.  I'm finally getting the results I should have gotten in the first place: very sharp images and a significant increase in the number of keepers.

According to Canon, "It was found that the adjustment of the circuit board was incorrect causing inaccurate auto focus." 

Before the adjustment, I was getting about 10 percent keepers.  Now, I'm getting about 70 percent.  The 30 percent I end up deleting are mostly repeats and/or poor technique (excitement causing vibration) with probably 30 percent of those due to an actual miss in focus.  This is probably more in line with how the lens should perform.

Wade

Greatland

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Re: Focusing Problem with 600mm f/4.0L IS II with 1.4X Extender
« Reply #18 on: May 03, 2013, 04:56:16 PM »
I have always had issues with the extenders with my previous lenses, even the 800mm with the 1.4 III extender...soft pictures when enlarged.  I took my new 600 II and my new 1.4 III extender to Tanzania back in February and my results were amazing...no more soft pictures even when enlarged to very large sizes...perhaps you need to have Canon look at your equipment?

Mt Spokane Photography

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Re: Focusing Problem with 600mm f/4.0L IS II with 1.4X Extender
« Reply #19 on: May 03, 2013, 05:44:54 PM »
To all,

Thanks for all your suggestions.  After going through extensive testing, I felt it had to be a problem with the lens itself so I sent it to Canon in late April.  It was returned early last week, and the difference is phenomenal.  I'm finally getting the results I should have gotten in the first place: very sharp images and a significant increase in the number of keepers.

According to Canon, "It was found that the adjustment of the circuit board was incorrect causing inaccurate auto focus." 

Before the adjustment, I was getting about 10 percent keepers.  Now, I'm getting about 70 percent.  The 30 percent I end up deleting are mostly repeats and/or poor technique (excitement causing vibration) with probably 30 percent of those due to an actual miss in focus.  This is probably more in line with how the lens should perform.

Wade

Interesting!  As I reread thru the posts, it became apparent that the lens probably had a problem.  I'm glad you have it working properly now.  I think issues happen more than people realize, and I've seen others complain that a lens is poor, when they just need to have it serviced.
 
In your case, we know that the lens is supurb, so with your obvious use of  proper techniques, the lens had to be at fault.
« Last Edit: May 03, 2013, 05:47:39 PM by Mt Spokane Photography »

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Re: Focusing Problem with 600mm f/4.0L IS II with 1.4X Extender
« Reply #19 on: May 03, 2013, 05:44:54 PM »