One For The Tech-Heads (Canon Related)

Spiritflier

Spiritflier

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Simon (Prefer 'Si')
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Evenin' all,

I've just bought an EF300mm f/2.8 L IS USM MK1 to use with my 5DMKIII... I've been using a Kenko Pro300 DGX 1.4x teleconverter with all of my Canon lenses with no problems whatsoever and I'd hoped to use it with the 300mm as well.

Unfortunately, the TC won't work with it and I can't for the life of me figure out why... It's not the converter 'cos it's working fine with my 70-200mm f/2.8 II and it works with the 300mm on my OH's 1000D! :shrug:

If anyone can come up with a reason (and possibly a solution), I'd be very grateful. Given that the IQ from the Kenko is so good, I'd really like to avoid having to get rid of it to buy a Canon 1.4x.

Thanks,
Si
 
What doesn't work? You mean it doesn't communicate correctly?
 
Is the focus swith set to AF? :)
 
I'm guessing so... It'll autofocus and the aperture reads correctly but as soon as you press the shutter, the frame number flashes constantly on the top screen and the camera simply locks up. I have to take the battery out to get it to work again. :shrug:

My Canon 2x MKIII works fine though so it's obviously something to do with the Kenko.
 
Do you have any custom functions set on the 5d3 relating to the lens button?

Might be worth trying to disable any settings for this to see how you get on.
 
Sounds like a quirk relating to the 300 2.8. Canon's big primes do communicate extra stuff that is presumably confusing the Kenko. 5D3 is also new of course. Suggest contact distributors (Intro2020) and see if there's a fix but I'm guessing not.

I've been testing a lot of TCs recently, on a 5D3 as it happens, and I did get a few strange things happening in live view with Kenko and Sigma.
 
RichardtheSane said:
Do you have any custom functions set on the 5d3 relating to the lens button...
Click to expand...

None that I know of Richard... I'll play around with a few things and see what happens. I've tried running the problem through Google and can't find results relating to this particular issue. :shrug:

HoppyUK said:
Sounds like a quirk relating to the 300 2.8. Canon's big primes do communicate extra stuff that is presumably confusing the Kenko...
Click to expand...

That's the only thing that makes sense to me as well... Everything else works well and the 300mm/Kenko combination works fine on my wife's 1000D so it's got to be something about the 5DMKIII and the 300mm combined!

DuncanDisorderly said:
Can you borrow a Canon 1.4xTC?
Be interesting to see if you get a difference.
Got to be one of the low fly bunch with one in their bag or maybe a camera shop will let you try.
Click to expand...

I don't know anybody local with a Canon 1.4x converter Duncan... I have a feeling that the simplest solution will be to sell the Kenko and buy a Canon instead. :thumbs:
 
Spiritflier said:
None that I know of Richard... I'll play around with a few things and see what happens. I've tried running the problem through Google and can't find results relating to this particular issue. :shrug:
Click to expand...

Page 321 of your manual, it's the button referred to as 'Lens'. Your 300mm F2.8 has buttons round the outermost rubber grip that can have functions assigned to them.

It may be of no consequence, but this is extra info that is communicated from the lens to the camera so could be responsible.
 
It was worth a try Richard but unfortunately, it didn't work! :(

Thanks anyway! :)
 
i am probably an absolute mile out here ,but wasn't there a work around with teleconverters where you could could cover one of the terminals (with tape)as a way to get them to work?
it might be worth searching on to see if its relevant to your situation
 
niko said:
i am probably an absolute mile out here ,but wasn't there a work around with teleconverters where you could could cover one of the terminals (with tape)as a way to get them to work?
it might be worth searching on to see if its relevant to your situation
Click to expand...

Actually, that would probably be a workaround in this situation :thumbs: It's the three pins that sit on their own on the end. It'll mess up the reporting though.

It's usually not a great idea when used to force the camera to AF when the f/number rises above f/5.6 (becuase the aperture has still been optically changed by the extender, so AF is poor, if it works at all) but at f/4 that obvioulsy doesn't apply here.
 
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If your TC works ok with all your other lenses then the chances are it's an incompatability with the lens. I've got one of the same TC's and it works with all my lenses from my 50 f1.4 right through to my Sigma 150-500 OS, although it wont AF with the 150-500, and it doesn't degrade the image much either. I did try a 2x Kenko TC on my Canon 70-200 2.8 MkII but it would't AF with anything but my 85 f1.8 for some reason so I got a 2x MkIII Canon instead and that is brilliant with the lens.
 
Well, taping up the three pins lost me AF and aperture but it did focus manually and it did take the shot! :thinking:

I could accept it being a compatibility issue if it didn't work on my OH's 1000D but it works fine on there! I guess it'll be a case of selling the Kenko and buying the 1.4x MKIII :shrug:

Thanks for all the suggestions,
Si
 
Loosing AF with pins taped... now that IS odd...

How about picking up a 1.4x II used? Can normally be had for about £170 and the kenko sells for about £100.
 
Spiritflier said:
Well, taping up the three pins lost me AF and aperture but it did focus manually and it did take the shot! :thinking:

I could accept it being a compatibility issue if it didn't work on my OH's 1000D but it works fine on there! I guess it'll be a case of selling the Kenko and buying the 1.4x MKIII :shrug:

Thanks for all the suggestions,
Si
Click to expand...

Really? LOL that must be a quirky combo you've got there!

Interesting comments from Modchild too. I've been testing the 2x Kenko Pro300 DGX and 70-200 Mk2 with no issues on a 5D2 and 5D3. If anyone's interested, I tested nine different telecons on three 70-200s and two cameras for Advanced Photographer magazine. For sharpness and AF performance too. That issue will be published mid-October.
 
Just to add another bit of confusion to the issue, I tried the Kenko and 300mm on a friends' 7D and it worked perfectly... That means it's just the 5DMKIII that's not working with it! :thinking:

Here's another thought... The 300mm is about 12 years old. Would it be worth sending it back to Canon for a 'service' just in case there's something they can do internally to sort it?
 
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