Canon 70D has issues with kenko TC, as reported for 6D and 5DIII

[ftico]

While this is my first post to this forum, I have been reading and learning from it for a while... so I thought it was time to try giving something back .

Yesterday for the first time, when I tried to use my Canon 70D with a kenko DGX (blue dot version) 2x extender and the Canon 400 5.6L, the camera basically froze, refused to turn off or write pictures to card. The only way to resume it was to remove the battery.

The same problem (or some variations of it) kept reappearing every time I try that combo. The teleconverter works fine with other lenses, and the lens works fine with other teleconverters. At first I could not figure out what was wrong... also because I successfully used that combo before!

Then I remembered I read something similar here regarding the 5D mark III:

http://www.canonrumors.com/forum/index.php?topic=4977.0

I thus realized that the reason for the new behavior was that I recently tried to AF microadjustment that lens (luckily, no need for that, or maybe needed just -1 in some situations).

I then switched off the AF microadjustements, and everything worked flawlessly again. By the way, the new Dual pixel AF works quite nicely with that combo, allowing AF at 800mm/F11 (sometimes it can hunt a bit, but it is fast enough to take pics of a perched bird)! Too bad you can't microadjust...

Hope this helps!

[scott]

 Canon 70D with a  Canon 400 5.6L

 is it "not to heavy" for the 70D   

[jdramirez]

I was seriously considering  the kenko,  but knowing this might be a possibility lead me right into the arms of  Canon.   pretty sneaky sis.

[ftico]

Regarding the 70D + 400mm 5.6L weight balance (even if a bit off topic I guess): it is a bit shifted towards the lens, but I find it very usable, and actually encourages you to hold the lens towards the front, which (IMHO) improves stabilization when hand-holding a telephoto.

I do hike quite a bit with the 70D + 400mm on my side, and it feels reasonably solid.

[AlanF]

Canon 70D with a  Canon 400 5.6L

 is it "not to heavy" for the 70D

A 500mm f/5.6 on a 70D is a lightweight compared with a 300mm f/2.8 on a 5DIII or 7D, which is perfectly usable!

[W507]

While this is my first post to this forum, I have been reading and learning from it for a while... so I thought it was time to try giving something back .

Yesterday for the first time, when I tried to use my Canon 70D with a kenko DGX (blue dot version) 2x extender and the Canon 400 5.6L, the camera basically froze, refused to turn off or write pictures to card. The only way to resume it was to remove the battery.

The same problem (or some variations of it) kept reappearing every time I try that combo. The teleconverter works fine with other lenses, and the lens works fine with other teleconverters. At first I could not figure out what was wrong... also because I successfully used that combo before!

Then I remembered I read something similar here regarding the 5D mark III:

http://www.canonrumors.com/forum/index.php?topic=4977.0

I thus realized that the reason for the new behavior was that I recently tried to AF microadjustment that lens (luckily, no need for that, or maybe needed just -1 in some situations).

I then switched off the AF microadjustements, and everything worked flawlessly again. By the way, the new Dual pixel AF works quite nicely with that combo, allowing AF at 800mm/F11 (sometimes it can hunt a bit, but it is fast enough to take pics of a perched bird)! Too bad you can't microadjust...

Hope this helps!

The blue dot 1.4 also refuses to work on my 60d and 70d with the 400 f5.6, but works perfectly with 1dmk2n. It also worked (and autofocused) on the 60d with a 100-400 L.
I have MFA on the 70d but the 60d does not have MFA so must be a different issue. Going to try your fix and see if i can get it working on the 70d.

Pity if it doesnt as i bought the converter specifically for this lens and body. Lucky for me its working on the 1D and images look great..

[candc]

I have the promaster 2x digital which is the same as the new kenko 7 element one and it works great on the 70d, I have been mostly using with the sigma 120-300 sport, with that lens it overexposes by +1 ev but the AF is just fine even for bif. Just for fun I tried it with the sigma 80-400 f4-5.6 and it still autofocuses. I also have tried it on the sigma 18-35 f1.8 and on that lens it is super sharp and turns the lens into a 36-70 f3.5 zoom

[weixing]

While this is my first post to this forum, I have been reading and learning from it for a while... so I thought it was time to try giving something back .

Yesterday for the first time, when I tried to use my Canon 70D with a kenko DGX (blue dot version) 2x extender and the Canon 400 5.6L, the camera basically froze, refused to turn off or write pictures to card. The only way to resume it was to remove the battery.

The same problem (or some variations of it) kept reappearing every time I try that combo. The teleconverter works fine with other lenses, and the lens works fine with other teleconverters. At first I could not figure out what was wrong... also because I successfully used that combo before!

Then I remembered I read something similar here regarding the 5D mark III:

http://www.canonrumors.com/forum/index.php?topic=4977.0

I thus realized that the reason for the new behavior was that I recently tried to AF microadjustment that lens (luckily, no need for that, or maybe needed just -1 in some situations).

I then switched off the AF microadjustements, and everything worked flawlessly again. By the way, the new Dual pixel AF works quite nicely with that combo, allowing AF at 800mm/F11 (sometimes it can hunt a bit, but it is fast enough to take pics of a perched bird)! Too bad you can't microadjust...

Hope this helps!

The blue dot 1.4 also refuses to work on my 60d and 70d with the 400 f5.6, but works perfectly with 1dmk2n. It also worked (and autofocused) on the 60d with a 100-400 L.
I have MFA on the 70d but the 60d does not have MFA so must be a different issue. Going to try your fix and see if i can get it working on the 70d.

Pity if it doesnt as i bought the converter specifically for this lens and body. Lucky for me its working on the 1D and images look great..

   I had this kenko TC, 60D and 400mm F5.6L and it's does AF on 60D with 400mm F5.6L, BUT the centre point is extremely unreliable... you need a very contrasty target for the centre point AF to lock on. The strange thing is the outer AF points work better. Same issue with 70D.

   By the way, it work perfectly with 6D... as long as you don't activate the MFA.

   Have a nice day.

   

[jrista]

I was seriously considering  the kenko,  but knowing this might be a possibility lead me right into the arms of  Canon.   pretty sneaky sis.

Also keep in mind that when using a Kenko on Canon, metering is off by one or two stops, depending on which TC you are using. You eventually pick up on that, but early on you'll find that most of your shots are overexposed. I still forget to compensate these days, which is why I finally just went and purchased the Canon TC instead...much less of a hassle having to always remember to change your exposure by an additional stop.

The real question is, is that slightly lower hassle worth twice the cost? The Keno DGX TCs are about half the cost of the Canon Mark III TCs...

[jdramirez]

I was seriously considering  the kenko,  but knowing this might be a possibility lead me right into the arms of  Canon.   pretty sneaky sis.

Also keep in mind that when using a Kenko on Canon, metering is off by one or two stops, depending on which TC you are using. You eventually pick up on that, but early on you'll find that most of your shots are overexposed. I still forget to compensate these days, which is why I finally just went and purchased the Canon TC instead...much less of a hassle having to always remember to change your exposure by an additional stop.

The real question is, is that slightly lower hassle worth twice the cost? The Keno DGX TCs are about half the cost of the Canon Mark III TCs...

 I'm trying to remember,  but I think I paid 150ish  for my 1.4 mkii.  I got it used and also had a discount.   it is perfect...  and I'm happy to have it when I need it.

[LetTheRightLensIn]

The interesting thing is that the very same 1.4x MC4 DGX and Pro DGX blue dots from Kenko are the only TCs that DON'T mess up when paired with a 5D3 and a 70-300L. They not only don't crash out in that case (as they do when paired with my 300 2.8 IS, especially if attached to a Canon TC+the 300 2.8- it makes the 300 2.8 AF become non-functional, even after removing the TC and turning off the camera the 300 2.8 AF will be totally gone! man was I freaked!!!! but removing the battery brings it all back) but they allow the 70-300L to deliver perfect f/8 AF even with old pre-f/8 AF firmware on the 5D3!!

So if you want AF with the 70-300L and a 1.4x TC make sure to get the blue dot MC4 DGX or the red dot Pro DGX Kenkos. Canon's own TCs totally fail and deliver horrible AF with the 70-300L whether you have the f/8 AF firmware installed or not and they don't report properly. Those two kenkos report properly and deliver excellent AF. AFAIK most other kenkos and all canon and other brand TCs fail with the 5D3+70-300L combo.

[Skulker]

........

I then switched off the AF microadjustements, and everything worked flawlessly again. By the way, the new Dual pixel AF works quite nicely with that combo, allowing AF at 800mm/F11 (sometimes it can hunt a bit, but it is fast enough to take pics of a perched bird)! Too bad you can't microadjust...

........

If you're using Dual pixel AF is there any point in setting AFMA? Won't it be like live view in that it works on the actual focus on the sensor not the separate focus system.

[ftico]

If you're using Dual pixel AF is there any point in setting AFMA? Won't it be like live view in that it works on the actual focus on the sensor not the separate focus system.

Correct, yet I also use the 400mm with conventional PD AF. So I do not need AFMA for DPAF, it is just that I have to remember to switch that off before I attach the teleconverter. In fact, i find it strange that a function that has no actual utility in liveview can compromise that mode...