Canon EOS-1D X AF at f/8 with the Kenko 1.4TC

[Loswr]

my 7 year old 1D Mark IIN and 8 yr old 1D Mark II paired with a third party TC works at f/11 just fine
~ while my 1DX wont.

I don't suppose you have a constant f/4 lens you can try with the Kenko 2x on the 1D X, to see if it works at f/8?

 

[Mt Spokane Photography]

5.6 plus 2x = f/11 - there's no camera that AF at f/11....


My 1D Mark IIN and your 1D Mark IV will work on f/8 but not f/11 - none does

hope this helps your inquiry.

My 1D MK III would AF at F11 with my 70-200mm f/4L and 2X TC. My 40D also worked at F/11 with some lenses. Obviously, you needed a non reporting TC, but it did Autofocus.

 

[AJ]

OK, to understand why this works, you need to understand the camera refuses to AF with the Canon extender because it's being told there is an f8 (or f11 for the 2X) lens on the front. The software of the camera then declares "hell no".

The Kenko converter is passing the f stop of the lens without the change in aperture. So the camera thinks there is an f5.6 lens on it. Now you still need decent light and a contrasty subject, more than without the telecenter, but it still works.

Why the -1? Because he camera is metering at f8 while being told it has f5.6. So before the photo is taken, it is metering wrong.

Yes, but:

The camera thinks it's metering at f/5.6 and shooting at f/5.6, while the actual metering is at f/8 and the exposure is a f/8. So - it doesn't try to control light by manipulating aperture. So why the need to dial in compensation?

 

[heheapa]

This sounds the f/8 AF can be enabled by a firmware release.
Just curious what's the reason that Canon not to enable that originally?
To clear the stock for 1D Mark IV before 1DX in stock?
If the AF works well on 3rd party teleconverter, there should be an easy workaround code for a firmware fix.
If canon can send me the firmware code then I can advise the changes for them

 

[TexPhoto]

Why? To sell more big aperture lenses? To cut down on complaints and returns of lenses not focusing perfectly at f8 in questionable light? Just to tick off people used to the f8 shooting? Who knows?

My guess is some very smart engineer said: listen we can focus really really good at f5.6, or just good at f8... Which do I want to be known for?

 

[spinworkxroy]

Does putting a 1.4x converter on a 400 f5.6 lens mean exactly the same thing as putting a 1.4x on a 70-300 f3.5-5.6 at 300mm?

Both will be at f8 right? Unless it's not the same thing with a variable aperture zoom lens. Or maybe it's just lens specific.
Reading the article, many people have errors connectiong the Kenko 1.4 to a 5D3 with a f5.6 lens

However, my 5D3 works fine with the Kenko with a 70-300 zoom lens at 300mm f5.6 (which is f8 with the TC)….
So maybe it doesn't affect everyone and every f5.6 lens..so it depends on your luck maybe?

 

[xps]

Does this teleconverter work with other bodies too? 60D with 100-400mm?

My personal opinion is, that the camera producers calculate what is profitable for them. So, some features will be restricted. Many of the electronic products we use each day are capable to be more powerful than we are allowed to use by the producers.

 

[MartinM]

Wonder if it would also work for the 5DIII.

I have used the folowing combo

5D Mark III + TC1.4x III + TC2x II + 70-200 L IS II USM and AF works -> 560mm

But, I tried it at an airshow and AF was not fast enough to capture the fast passing aircrafts. For static birds or so, it worked fine.

Cheers
Martin

 

[spinworkxroy]

Wonder if it would also work for the 5DIII.

I have used the folowing combo

5D Mark III + TC1.4x III + TC2x II + 70-200 L IS II USM and AF works -> 560mm

But, I tried it at an airshow and AF was not fast enough to capture the fast passing aircrafts. For static birds or so, it worked fine.

Cheers
Martin

That's because your 70-200 is f2.8..even with 2x TC it's only F5.6 which is supposed to work.
The question people are asking is does the tC1.4 work when the aperture becomes f8.

For me, i don't own any prime f5.6 lens so i don't know but i've only ever tried it on a 70-300 f5.6 variable aperture zoom lens and at 300mm with the TC it works fine at f8…maybe it's because it's not a Canon lens?

 

[SambalOelek]

I've used Kenko 2x with the lovely Sigma 100-300 f/4 on 5D III, and it worked like a charm. Very sharp and snappy AI Servo AF with both manual and automatic.

Sigma 100-300 f/4 + Kenko 2x (effectively @ f/8) = Works 100%
Sigma 100-300 f/4 + Kenko 2x + Canon 1.4x (effectively @ f/11) = Only automatic AF point selection, fast lock
Canon EF 70-300 f/4-5.6 L + Kenko 2x (effectively @ f/8-11) = Slow/difficult to lock focus

 

[Marsu42]

Canon EF 70-300 f/4-5.6 L + Kenko 2x (effectively @ f/8-11) = Slow/difficult to lock focus

... a 1.4x tc is the absolute max for the 70-300L unless you mf, but imho the iq with the 1.4x Kenko is "just" ok so I wouldn't want to try a 2x.

 

[Childeric]

What a surprise !

I mentioned exactly that almost two months ago ;-)

http://www.canonrumors.com/forum/index.php?topic=7980.msg145491#msg145491

By the way, it seems to me that overexposure is more than one IL, and the correct aperture is reported by the 1dX, strangely.

 

[Peerke]

Maybe known, but anyway.

A Kenko 1.4 PRO 300 DG won't do the trick on my 7D with 400 5.6. I guess you need a DGX :'(.

Just had a look on the Kenko site. It should not be possible according to them. They state that:

"Most Canon EOS camera bodies are programmed to shut down auto focus if the calculated effective aperture for the lens and teleconverter is smaller than f/5.6, the Kenko Teleplus PRO 300 converters work the same way"

 

[SambalOelek]

Canon EF 70-300 f/4-5.6 L + Kenko 2x (effectively @ f/8-11) = Slow/difficult to lock focus

... a 1.4x tc is the absolute max for the 70-300L unless you mf, but imho the iq with the 1.4x Kenko is "just" ok so I wouldn't want to try a 2x.

In fact, I found that the bare lens performance at 300mm is only okayish, which is somewhat disappointing considering the max aperture. I have two of these so I may run a quick check to see if there's any discernable difference.

 

[Marsu42]

In fact, I found that the bare lens performance at 300mm is only okayish, which is somewhat disappointing considering the max aperture. I have two of these so I may run a quick check to see if there's any discernable difference.

The 70-300L is not the sharpest lens on the block, but it is a is good tradeoff between short length, reasonable weight (!), L build quality, nice bokeh, very good af performance and moderate price - don't forget the price difference to the 70-200/2.8 and tele primes. But you are correct, the 1.4tc solution definitely doesn't produce professional grade shots @100% crop, it's just "nice to have" for the low cost of the Kenko.

But since you mention it: there are qc issues, for the iso crops they had to get another sample (see link below). But at least my sample is very sharp @300mm on crop, i.e. using the lens' center. If it isn't it's simply a shutter speed issue because with low shutter speed + IS I can get good pictures, but for max. sharpness it's still 1/500 or faster.

http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=738&Camera=453&Sample=0&FLI=0&API=0&LensComp=738&CameraComp=453&SampleComp=1&FLIComp=0&APIComp=0

 

[Arthur Morris]

It seems that firmwares later than 1.02 disable to ability of the 1DX to AF at f/8 with the Kenko Teleplus PRO 300 DGX 1.4x AF Teleconverter with all the accompanying benefits....

Does anyone know if it possible to save the firmware that is on the camera?

Arthur Morris www.BIRDSASART-Blog.com

 

[Arthur Morris]

I don't understand the need to dial in -1 stop compensation? Doesn't the light loss caused by the TC automatically result in a lower metered exposure? I'm confused

It looks as if you nailed this one....

 

[Arthur Morris]

Maybe known, but anyway.

A Kenko 1.4 PRO 300 DG won't do the trick on my 7D with 400 5.6. I guess you need a DGX :'(.

Just had a look on the Kenko site. It should not be possible according to them. They state that:

"Most Canon EOS camera bodies are programmed to shut down auto focus if the calculated effective aperture for the lens and teleconverter is smaller than f/5.6, the Kenko Teleplus PRO 300 converters work the same way"

Childeric, Not to be a pain but that is not exactly what you wrote. In fact, what you wrote is not at all what I wrote .

 

[Marsu42]

It seems that firmwares later than 1.02 disable to ability of the 1DX to AF at f/8 with the Kenko Teleplus PRO 300 DGX 1.4x AF Teleconverter with all the accompanying benefits....

Holy crap, so it's like "We own you and all your camera bodies" because if af @f8 doesn't work w/ the Canon tc, it shouldn't work at all? Argh - I read this is the same with the latest 5d3 firmware, can anyone confirm this?

 

[Arthur Morris]

Agree. Not very nice at all. I have written some folks at Canon for confirmation.... Will advise.

Arthur Morris/www.BIRDSASART-Blog.com