Just bought a new Canon EF 70-300L IS USM lens.

[Marsu42]

You say that with the Kenko 1.4x the 5D3 autofocuses ... will this combo work with the 100-400 also as it will also result in a max aperture of f/8?

The Kenko tc tricks the camera into focusing @f8 while the Canon tc makes the camera do what its supposed to to - disable af @f8 to sell more 1d series cameras (or 5d3 sometime in 2013). The Kenko also works on *all* lenses, while the Canon is only designed for a small selection.

 

[East Wind Photography]

I know that on the Canon, the extenders need to be able to extend into the rear of the lens a slight bit. Those lenses with optics right up to the mounting ring wont accept the canon extender.

RandonOrbits, that applies to the Canon 1.4x, because of its design. The Kenko design is different, and allows it to be used over the entire 70-300L range. I don't have either tele-extender, so this isn't from personal experience, but that seems to be the consensus. And as for the extender eating another stop of light and impacting sharpness, I think that's the expected price you pay for gaining the reach.

 

[Lnguyen1203]

Lnguyen1203, are you saying that whenever you mount your Kenko 1.4x to your 70-300L you set the 5D3's exposure compensation to +1?

-1. You need to substrate light, which is a bit weird.

 

[Random Orbits]

RandonOrbits, that applies to the Canon 1.4x, because of its design. The Kenko design is different, and allows it to be used over the entire 70-300L range. I don't have either tele-extender, so this isn't from personal experience, but that seems to be the consensus. And as for the extender eating another stop of light and impacting sharpness, I think that's the expected price you pay for gaining the reach.

Yes, I agree. I'm saying that for those that already have a Canon extender, it'll work on the 70-300L on the long end and that you might not need to get extender specifically for the 70-300L.

 

[Quasimodo]

Have to say that your thread is a pleasure to read It is invigorating (not sure if that is spelled correctly..?). Love your enthusiasm. Congrats on what obviously seems to be a great lens

 

[Lnguyen1203]

I did a quick and dirty experiement today to check the exposure compensation.

#1 photo: 5D3, Kenko 1.4X TC, 70-300L, 0 EV, blown highlight is evidence, couldn't be recovered in LR4

#2 photo: same as above with -1 EV compensation, much better, some highlight on the bird is still blown.


These are quick and dirty experiements, so appologize to those of you who are purists

 

[Lnguyen1203]

I did a quick and dirty experiement today to check the exposure compensation.

#1 photo: 5D3, Kenko 1.4X TC, 70-300L, 0 EV, blown highlight is evidence, couldn't be recovered in LR4

#2 photo: same as above with -1 EV compensation, much better, some highlight on the bird is still blown.


These are quick and dirty experiements, so appologize to those of you who are purists

and just for kick, I swapped out the Kenko for the Canon 1.4X III. AF is a bit sluggist and the lens makes a grinding noise. I put the combo on my 1DX and the same noise persists. My hummingbirs were not cooperating, so I went out and shot an Amerian Kestrel instead. The IQ is fantastic, but I guess we know that already. So, if Canon can fix the AF issue with firmware, this is in fact a viable option.

 

[miah]

Thanks for availing the results of your experiment, Lnguyen1203, that's really helpful. But just to be clear, the Canon 1.4X III only fits/works on the 70-300L throughout the latter part of the zoom range, right? Zoom it in too far and glass meets glass--ouch--right?

 

[Lnguyen1203]

Thanks for availing the results of your experiment, Lnguyen1203, that's really helpful. But just to be clear, the Canon 1.4X III only fits/works on the 70-300L throughout the latter part of the zoom range, right? Zoom it in to far and glass meets glass--ouch--right?

Correct.

 

[miah]

Your kestral looks awesome, Lnguyen1203. Is that image cropped? If not, even with the 1.4x on the 70-300L you were able to get awfully close to that bird!

 

[Lnguyen1203]

Your kestral looks awesome, Lnguyen1203. Is that image cropped? If not, even with the 1.4x on the 70-300L you were able to get awfully close to that bird!

It is crop, but yes, I was fairly close to the bird, may be 15 yards or so.

 

[FlowerPhotog]

I had posted a shot showing the excellent resolution of the 70-300L, with the Kenko 1.4X teleconverter several months ago.
http://www.canonrumors.com/forum/index.php?topic=4977.msg110430#msg110430

My series of shots, ending up a 100% crop of a shot at 420mm are on the third page of that thread - think the link above should take you to that page.

That thread was started talking about the problems with the Kenko and some lenses on the 5DMkIII - turns out the problem is solved by turning AFMA off. The 70-300L was one of the lenses I didn't have a problem with

 

[Richard8971]

I am seriously thinking about getting one of the Kenko tele's, but has anyone had any experience using the 2X tele's with this lens?

D

 

[Lnguyen1203]

I am seriously thinking about getting one of the Kenko tele's, but has anyone had any experience using the 2X tele's with this lens?

D

I wouldn't if I were you. The 2X would rob you 2f stops and now you will ha f11 as the largest aperture. Meaning you can't use AF. Also, the 2X should be reserved for the very best, sharpest telephotos. If you need more reach, the Kenko 1.4x is OK.

 

[Marsu42]

I am seriously thinking about getting one of the Kenko tele's, but has anyone had any experience using the 2X tele's with this lens?

The 2x will most likely be worse than cropping, so it'd be only an advantage for very high iso shots - imho the 1.4x is the max for the 70-300L that makes any sense, not only because of the f11 problem.

 

[GMCPhotographics]

This is a lens which has impressed me more and more I use one. On paper, it's a sharp but over priced lens. But in real world use, it's a fantastic performer. My only gripe is the lack of a tripod collar and it's low magnification at closer focus distances. Other than that, it's superb.
It's also a lens which came in for some really harsh objections when it was first launched. Sure it was expensive, considering most 70-300 lenses were consumer grade zooms. This lens was cut from different cloth, it's a profressional lens and a pretty goon one too. Now it's a few years after it's launch, it's new price has come way down to a far more realistic level. It's still not a cheap lens per-say, but it's good value considering it's strong performance. It's relatively small, light and it's a great range to have.
Personally, I'm holding out for a new 100-400 instead....which is going to be over priced and heavily maligned in the various forums on it's launch....but after a year....it'll come down in price somewhat.