Kenko TC and AF at F8

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lorenbc said:
AlanF said:
Loren
I do bird photography and use spot autofocus with the centre spot. I have read that the outer zones are more sensitive but the centre focused well.
Alan

I'll try spot; the regular center point just hunts with the 100-400+1.4.

Thanks.

Loren
Be sure its the Pro 300 DGX version. There are some who say that only recent production of these will AF at f/8.
I did use the center poing, but not spot. My Canon 10D doesn't even have spot, but it worked very well as did my 5D MK III.
 
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Mt Spokane Photography said:
lorenbc said:
AlanF said:
Loren
I do bird photography and use spot autofocus with the centre spot. I have read that the outer zones are more sensitive but the centre focused well.
Alan

I'll try spot; the regular center point just hunts with the 100-400+1.4.

Thanks.

Loren
Be sure its the Pro 300 DGX version. There are some who say that only recent production of these will AF at f/8.
I did use the center poing, but not spot. My Canon 10D doesn't even have spot, but it worked very well as did my 5D MK III.

Yep...it's definitely PRO DGX with the green (or was it blue) dot on the box (I don't have the box handy). Actually. just remembered my wife has one, too, so I'll try hers, too, and see if it's any different.

Loren
 
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After reading Authur Morris blog, I went for the Kenko 1.4 Teleplus for use with my 70-300L f4-5.6 and Canon 5D3. I'm happy to report that the 5D3 retains all 61 points AF. The AF at F8 isn't bad at all and the IQ is useable. I have also a 300F2.8 + 1.4X and 2X, but for a walk around lens, the 70-300L is much lighter and the Kenko 1.4X does a pretty good job. Will test some more in the weeks to come. The attached photos are shot at 1/2500, f8, ISO 1250, 420mm. The focus is spot on as in the second photo.
 

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lorenbc said:
Yep...it's definitely PRO DGX with the green (or was it blue) dot on the box (I don't have the box handy). Actually. just remembered my wife has one, too, so I'll try hers, too, and see if it's any different.

Loren
I checked my box, its still laying here. It has a blue dot. That usually means some sort of rework or upgrade has been incorporated.
I do set the 100-400Lfocus distance limiter to the 6.5m - infinity setting and then the lens does not run thru its entire AF range. That makes a huge difference in time to find focus.
 
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Mt Spokane Photography said:
lorenbc said:
Yep...it's definitely PRO DGX with the green (or was it blue) dot on the box (I don't have the box handy). Actually. just remembered my wife has one, too, so I'll try hers, too, and see if it's any different.

Loren
I checked my box, its still laying here. It has a blue dot. That usually means some sort of rework or upgrade has been incorporated.
I do set the 100-400Lfocus distance limiter to the 6.5m - infinity setting and then the lens does not run thru its entire AF range. That makes a huge difference in time to find focus.

I found something interesting today; I grabbed my wife's copy of the 1.4 DGX Pro and noticed that hers has a blue dot...mine has a green dot...and when I tested it with the 7D+100-400, the center point worked! So, it would seem that the blue dot version has some enhancement above and beyond the green dot version. So, needless to say, I replaced the green dotted copy in my wife's bag and went on my merry way <grin>. She never uses it anyway!
 
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I never did get to test mine, I have been recovering from hand surgery, and thought maybe I could try it with my 100mm L this morning. The TC was totally dead, and froze up the camera. After trying it with my 100-400mmL and on my 10D with the same results, I made sure there were no problems with the contacts, and then packed it up to go back for a refund. I do not want another from the same lot.
Now, I'll probably just wait and see if Canon upgrades the 5D MK III. if not, I'll get another Kenko.
 
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WesternGuy said:
Well, I guess this all changes for 1D X owners with the issue of the upgrade 1.1.1. I have made the upgrade and now all I have to do is test it out and see what happens.

Worked decently today with the 600 II and 2xIII. There was some focus hunting when shooting birds in dense foliage with backlighting, and I thought, hmmmm, is this because of the 2x? So I switched to the 1.4xIII, and the hunting was no different. It was a bit better with the bare lens, but still not perfect. When I moved to a different angle that eliminated the backlighting, it was fine.
 
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I think that the system was not intended to do well at f/8, but they decided that it was good enough for most usage. Certainly, my 5D MK III did very well with the Kenko 1.4X and 100-400 while at 400mm. At least until the Kenko died. Everything is working fine since I removed the TC.
 
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neuroanatomist said:
There was some focus hunting when shooting birds in dense foliage with backlighting

Here's a shot that shows the bird and surround, a tough job for any AF system. This was with phase AF, and I haven't done an AFMA yet (need to find a deserted football field for that!). Might be a little back-focused, I think.

Shot is with the 1D X and 600mm f/4L IS II + 2xIII, 1/320 s, f/8, ISO 4000. Original and a 100% crop to show detail, which is quite good, IMO.
 

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Wow, the backlighting is tough to deal with. It might be a hair backfocused.
I had the older non is 600mm f/4. It was too much for me to haul around and setup, but it did a great job. I finally resigned myself to making do with my 100-400mmL, and its pretty good.
 
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