Art Morris speaks to sharp IQ and f/8 AF with 1D X, 800mm f/5.6 L and Kenko 1.4x

[jrista]

I've been reading Arthur Morris' blog for around 9 months now, and particularly heavily since around May. He is an extremely talented bird photographer, well-known for his use of teleconverters and f/8 AF in Canon 1D series bodies. Since the advent of the 1D X and the first time ever that the 1D series from Canon does not officially support f/8 AF, Art (along with many other professional bird and BIF photographers) have naturally looked for a way around the problem. You can read about arts experiences with the Canon 1D X, Canon EF 800mm f/5.6 L IS, and Kenko 1.4x Teleplus Pro 300 DGX teleconverter for functional 1120mm f/8 that produces sharp, professional results:

http://www.birdsasart-blog.com/2012/08/30/mega-amazing-discovery-800-f5-6-1-4x-tc-canon-eos-1dx/
http://www.birdsasart-blog.com/2012/09/02/100-proof-and-lots-more/

Seems the 1D X works superbly at f/8 with the Kenko TC.

[Mt Spokane Photography]

Although he was not able to get the kenko 1.4 X to work with the 5D MK III, others have ones that work well on 5D MK III at f/8.
I'm thinking of dumping my Canon TC's and buying Kenko.  It would be a even trade.  I guess I'll try a kenko first though.

[neuroanatomist]

I wonder...would the Kenko Teleplus PRO 300 DGX 2x AF Teleconverter allow AF with a 1D X and a 500mm or 600mm f/4L IS II lens??

[jrista]

I wonder...would the Kenko Teleplus PRO 300 DGX 2x AF Teleconverter allow AF with a 1D X and a 500mm or 600mm f/4L IS II lens??

There was a thread on another forum linked to in one of the links in is blog. One of the participants did do a test with the Kenko and a variety of lenses and bodies. The "bug" seemed to be limited to only a couple lenses on a couple bodies, namely the 5D III. Most lenses seemed to work with the Kenko 1.4x. There are also two different Kenko 1.4x TC's that seem to be frequently used. The PRO 300 DGX (which I own myself) is fully pinned and generally behaves like a Canon, except for the fact that it doesn't prevent AF at f/8 (although it is not guaranteed to work.) The Kenko 1.4x MC4 DGX is not fully pinned, and effectively behaves like a taped Canon 1.4x, so it seems to work pretty well on all bodies.

For those who might wonder, the optics of the PRO 300 DGX seem ever so slightly better, but both Canon Mark III TC's are superior in the edges/corners compared to the Kenko TC's. Overall the Kenko TC's rate higher than any other third-party TC from an optical standpoint, but if you want/need maximum IQ and have an f/8 body, the Canon EF 1.4x TC III and Canon EF 2x TC III will offer better edge and corner performance.

[neuroanatomist]

I wonder...would the Kenko Teleplus PRO 300 DGX 2x AF Teleconverter allow AF with a 1D X and a 500mm or 600mm f/4L IS II lens??

There was a thread on another forum linked to in one of the links in is blog. One of the participants did do a test with the Kenko and a variety of lenses and bodies...Most lenses seemed to work with the Kenko 1.4x.

Sure, but the Canon 1.4x will also AF just fine with an f/4 supertele. My question is will the Kenko 2x allow AF with a MkII f/4 supertele on a 1D X...

[heptagon]

Sure, but the Canon 1.4x will also AF just fine with an f/4 supertele. My question is will the Kenko 2x allow AF with a MkII f/4 supertele on a 1D X...

Bonus questions:
Will it work at low light? and with the outer focus points?

Bob from lensrentals wrote that the F/5.6 focus points around the center are more accurate than the F/2.8 focus points for some lenses. (Odd, but that's how it is.)

[jrista]

Sure, but the Canon 1.4x will also AF just fine with an f/4 supertele. My question is will the Kenko 2x allow AF with a MkII f/4 supertele on a 1D X...

Bonus questions:
Will it work at low light? and with the outer focus points?

Bob from lensrentals wrote that the F/5.6 focus points around the center are more accurate than the F/2.8 focus points for some lenses. (Odd, but that's how it is.)

As far as I know, it will work with any of the f/5.6 points, but not the ones that require f/4 or higher. I get rather confused about what points support what in the 1D X...I know there are 41 cross-type points, but to my recollection some (the outer sets) are only cross-type at f/4 or faster. I believe at f/5.6 the outer 40 cross-type points become horizontal line sensors. I don't see why they would be disabled...however unless you have superb light, I doubt they would work well, or at all. I believe it is primarily the centeral f/5.6 standard precision cross-type sensors that work at f/8.

As for low light, in my experience with my own copy of the Kenko 1.4x PRO 300 DGX, it really does need good light to AF. AF is also slowed down like with a Canon TC. I am admittedly using a 7D with 19 cross-type points rather than a 1D X with 61 points...so I can't speak authoritatively. I've used the Kenko with both an EF 100-400mm f/4.5-5.6 and EF 300mm f/2.8 L II...obviously the L II works a hell of a lot better as its f/4, but even that lens struggles as light drops in the evening, and pretty much stops AFing when light drops too low. I would be surprised if AF worked in honest-to-god "low light" like a bare lens would with the Kenko, and if it did, you would probably have better luck manually focusing.

[Tom W]

The Kenko 1.4x MC4 DGX is not fully pinned, and effectively behaves like a taped Canon 1.4x, so it seems to work pretty well on all bodies.

I have the 5D3 and Kenko 1.4x MC4 DGX teleconverter. It works well in moderate to good light with the 5D3 but there is some moderate vignetting at extreme corners. The price we pay for a 140-560 mm lens, I suppose.

It also works well on the 5D3 when stacked with the Canon 2X Mk III (or Mk II) on the 300/2.8 - better than stacking the Canon 1.4 and 2X which focus very erratically. It seems that the Kenko slows down AF a bit and avoids the rapid back/forth focus search that occurs with the Canons stacked.

It seems that the 7D's AF system is not as sensitive, and I had trouble with any f/8 combination in less than perfect light and a high contrast subject. It was very erratic, and would not obtain AF lock most of the time.

One word of warning - don't try to set up microadjust with the teleconver & 100-400 combination - I did this and the camera started locking up. Had to pull the battery to reset it and release the shutter. When I removed the microadjust for that combination, it worked fine again.

[romanr74]

Is it only me who sees a large clear(er) circle in all of these picutres? Is this the TC-Lens-Combination not working properly?

[xROELOFx]

i noticed this too. it looks like there is reversed vignetting? instead of darker corners, the corners look lighter. i wonder if this is a side effect of using the extender?

[romanr74]

is it the vignetting correction doing something it should not do, because the camera doesn't know there is a tc attached to the lens?

[jrista]

is it the vignetting correction doing something it should not do, because the camera doesn't know there is a tc attached to the lens?

Someone on BirdsAsArt asked the same thing. Art Morris has a fixed vignette correction setting that is applied to all of his photos. It seems like he missed it on a couple shots that needed some slight manual adjustment of that vignette correction, which is why the corners look fairly light in some of those shots.