Elliott Design Loc: West Tennessee

Purchased a Kenko 1.4 300 Pro for use with a Canon 100-400 L on my 7D ii. On first use, received error message that there was a communications problem with the lens and to clean the contacts. Tried that and got it to recognize the converter with the lens after removing it and re-attaching a few times, but was still erratic and got the error message several more times. Seems that in low light it would be OK most of the time but in brighter light it would fail every time. Tried several aperture/f-stop/iso combinations and the faster the shutter speed the more failures showed up.
Tried the converter with my 100 L macro and it completely locked up the camera, could not even turn it off, had to remove the battery to shut down. Tried this a few more times and had to remove the battery every time to shut down, decided the camera was not going to play nice with this converter and either of my lens which is a shame as the few shots that it did work on the sharpness was better than enlarging an area to the same size without it.
Don't know if anyone has experienced this with their 7d ii and other teleconverters but this particular model Kenko doesn't work with mine.
Works good without a fault with either lens on my T3i so guess I'll keep it for that camera.

Old Timer Loc: Greenfield, In.

I recently purchased the 1.4 also. I have the 60D and not a problem on it. How ever I am not sure about it. Some times I can get a good sharp picture and the next time not. I am still playing with it and trying to figure it out. For landscape it seems alright. But I wanted it mainly for birding and up close, and that is where I am having trouble.
I seem not to get sharpness and IQ that I want. With out the TC I get a pic that I can crop that is better than I can get with TC.

Lupane Loc: Gainsville, Ga.

The Canon 1.4x, II works fine with the 100-400L II & 7DM2 some of the time depending on the amount of light available. The 1.4 Kenko worked with the 70-300L except for some moments of focus hunting...There are several discussions about these combinations in the internet and possibly here at the UHH. Hope the problem can be cleared.

Lupane Loc: Gainsville, Ga.

Elliott Design Loc: West Tennessee

No problem with the quality, I was satisfied that it was better than enlarging, seems to match up good with the lens sharpness, it's just my 7d ii that doesn't like it. My older T3i plays nice with it, might be a firmware problem with the new camera.

Elliott Design Loc: West Tennessee

I'd considered the Canon 1.4 version III but heard good reports on the Kenko having good IQ so that's what I went with, maybe next time around it'll be the Canon which I would expect to be 100% compatible. Appears lots of people are having problems with the 7d ii working well with several lens combinations. Love the camera and have no complaints about it while using my Canon lenses, just seems to be third party equipment that is a bit out of it's capabilities. Oh, and thanks for the list below, according to the list you would have to use manual focus for the 100-400L, I had no problem with the AF whenever the camera recognized that lens and converter.

Lupane Loc: Gainsville, Ga.

Glad to be of some help. I currently use the 7D M2 with the 100-400L II sometimes I have used the Canon 1.4x II. There are times when the AF works flawlessly but it has its moments when it refuses to focus. In all honesty, I prefer not to use the extender.

yaterman96 Loc: Southern North Carolina

Its like buying a tripod,people will buy a cheep one an later wish they had got a good one. Save yourself some hassle an get the one that goes with the camera. For the canon, the 1.4 TC lll , is the best.

RichardSM Loc: Back in Texas

Sounds more likely a electrical handshake issue problem, the 7D MK ll is of a newer design then the old Kenko. 1.4 teleconverter. Purchase the Canon 1.4 ll TC to insure proper match up.

gemlenz Loc: Gilbert Arizona

I gave up on TCs after having 2 bad experiences. Soft focus was the main issue. I had a Canon 1.4 and a Kenko 1.4. Returned both of them.

canarywood1 Loc: Sarasota,Florida

Must be the camera, I use a Canon 6D with the kenko 1.4 and a Canon 24-105 and a Tamron 70-300 and no problems whatsoever.

Elliott Design Loc: West Tennessee

Well, not all together the price, if it was I wouldn't have a 7dii and L glass, it was because of reports that the IQ was as good as the Canon tele. I have no problem with the quality, the images were good, it just doesn't like this particular camera, works fine on either of my T3i's.

Elliott Design Loc: West Tennessee

That's probably the issue, it connects up firm and when it works it works quite well, there's just a little glitch in the combination that makes it too erratic to use without taking a chance of missing a shot.

Elliott Design Loc: West Tennessee

I'm sure it's the camera not communicating with the older converter, that's the problem whenever you get a new version of something, some legacy equipment might not function with it. I and many others are still waiting on Microsoft and Canon to get together on the image codecs so as to view the CR2 files in Explorer. Strange that Picasa, and several other "free" image viewers have already got the updates done.

Haydon

I've successfully used the 1.4x on my 70-200 2.8L II and my 500 F4L with little to no image degrading. Teleconverters are very lens specific. I know many people use third party with their own levels of success. IMO it's a crap shoot once you begin to introduce third party.