Kenko 1.4 tele converter not working with canon 70d


fcast 6 10
2 Oct 2014 9:59PM
I have just upgraded my camera from a 650d to a 70d and my 1.4 converter locks my 70d up, its not just
a case of manual focusing, it locks the exposure and the shutter does not work, you can change a few setting
but the camera won't even switch off, you have to take the battery out! the thing is it still works perfectly
with the 650d (auto focus even at f8) i have tried it with all my lenses
I'm worried that there is something wrong with the 70d as i would have though it should be compatible
apart from the issue with the converter everything else is ok with the 70d
any advice welcome

Frank

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gary_d 11 576 13 Wales
2 Oct 2014 10:05PM
I tried a non Canon converter on my 5D2 and it did the same thing but sorry I can not offer an explanation, I bought the Canon one and works perfectly.
2 Oct 2014 11:37PM
Some of Kenko 1.4 converters are not for EF-s use. So their performance on EF-s cameras or with EF-s lenses may be random. What lens do you use it with?
fcast 6 10
3 Oct 2014 5:14PM
I use it with the canon 400mm f5.6 and the Tamron Di 70-300 sp f4-5.6, both of whitch work great with the 650d including auto focus at f8
3 Oct 2014 7:03PM
Long shot but have you tried cleaning the contacts
fcast 6 10
3 Oct 2014 8:32PM
yes everything is clean also camera brand new tele as new
4 Oct 2014 10:44AM
mikehit 9 8.0k 13 United Kingdom
4 Oct 2014 12:46PM
My 7D will AF fine with the 100-400 + 1.4x Kenko tc, but my 70-300 with tc rarely did in anything other than excellent light with a high-contrast subject. So it seems to be very dependent on the lens and the body. But whether the 7D counts as a 'non-Pro body' I don't know.
fcast 6 10
4 Oct 2014 5:51PM
Thanks for the reply's its not the auto focus I'm worried about its the locking up of the camera every time its fitted,
i guess i will just sell it and splash out a bit more on Canon's version
ElSid 11 9 United Kingdom
9 Oct 2014 4:12PM
I suspect that this issue may be connected to the new focusing system that 70D uses for the live view option. There's probably been some very minor change in the way the AF communicates with the lens that the converter can't cope with hence the lock up.

This is a very similar problem to that found with old Sigma lenses and digital EOS bodies, Canon changed a protocol connected with aperture control and as a result digital EOS and some late model fim bodies either error out (Err99) or lock up totally - my EOS30 film body locks up totally and like your 70D only battery removal will free it.

Sadly it looks like a new converter is your best bet...


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