September 21, 2014, 12:38:46 AM

Author Topic: stacking up 2x+1.4x (both Mk 2's) on a 70-200 f2.8 L IS & Canon 5d Mark iii  (Read 3087 times)

bonvoyage

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Is it possible to stack up two extenders 1.4x Mk2 + 2x Mk2 on a canon 70-200mm f2.8 L IS lens with Canon 5d Mark iii ?
With the recent firmware update i reckon its possible to autofocus with the center point @ f8.

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neuroanatomist

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You can physically stack them (but not the MkIIIs).  I'm not even sure both will report - IIRC, you'll see f/5.6.  But the IQ will be worse than just cropping...
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Mt Spokane Photography

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Yes, I've don it with a number of lenses.  The 1.4X goes next to the camera, and the camera only sees the 1.4X.  I could mount it to my f/4 lenses and get autofocus at f/11 that way.  AF at f/11 is hit and miss.
Here are a couple I took recently with both TC's, my MK III, and 70-200mm MK II. The aperture was wide open.  This was before the f/8 firmware update, it wasn't needed when you stack TC's.
 

 
 

wickidwombat

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Is it possible to stack up two extenders 1.4x Mk2 + 2x Mk2 on a canon 70-200mm f2.8 L IS lens with Canon 5d Mark iii ?
With the recent firmware update i reckon its possible to autofocus with the center point @ f8.

not the genuine canons
but a kenko 1.4 will stack on a 2x however on my mk3 it doesnt work properly and is really flakey
aperture on the top display flickers between f8 and f5.6 (I havent tried it since i upgraded firmware though)
I should try

On my 1Dmk3 the combo wrks fine though at f8
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GMCPhotographics

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I regularly use a 2x TC mk II with mine. It's nearly as sharp as a 400 f5.6L but it's AF is a lot slower. It's heavier and quite a lump to use. The real world focal length is petty simular too.
I've tried to stack my 1.4x III anf 2x mk II and the results needed a fair amount of stopping down get a reasonable level of sharpness. The exposure was a little dark and it really needed a tripod to stabilse the thing. Mine, curiously would AF in bright lit scenes using the centre points but it was very inaccurate and jumpy. Certainly not reliable. I have used the 70-200 and 2x combo on a 7D and wide open it's not as sharp as I'd like and the contrast is lacking. But it was an easy way to get to an effective 600mm+ without going down the big glass route. 

MiceBass

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Has anyone ever tried to see how many extenders (of any different makes) can be stacked on and still have a picture (of any quality) taken?

Am I the only person strange enough to be thinking about this?

rs

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I had a 70-200/2.8 IS mk I and the mk II 1.4x and 2x TC's - I tried them stacked with my 40D. From what I remember the wide open aperture was reported as f5.6. Even though it went through the motions of AF, it was terrible with loads of slow hunting and very frequently not locking on. The picture quality was awful at any aperture - shooting without any TC's and tightly cropping gave better results.
5D II | 24-70 II | 70-200 II | 100L | 40 | Sigma 50/1.4 | 40D | 10-22 | 17-55 | 580 EX II | 1.4x TC II

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neuroanatomist

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Is it possible to stack up two extenders 1.4x Mk2 + 2x Mk2 on a canon 70-200mm f2.8 L IS lens with Canon 5d Mark iii ?
With the recent firmware update i reckon its possible to autofocus with the center point @ f8.

not the genuine canons

As stated above, the 'genuine Canon' TC's the OP lists can be stacked - they are the MkII versions.  The 2xIII has two additional elements compared to the 2xII, and there's not enough space at the back of the rear element to accept the protrusion of the 1.4x TC. 

Note that you can stack a 1.4xIII and a 2xII - the limitation is for the 2xIII.
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wickidwombat

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Is it possible to stack up two extenders 1.4x Mk2 + 2x Mk2 on a canon 70-200mm f2.8 L IS lens with Canon 5d Mark iii ?
With the recent firmware update i reckon its possible to autofocus with the center point @ f8.

not the genuine canons

As stated above, the 'genuine Canon' TC's the OP lists can be stacked - they are the MkII versions.  The 2xIII has two additional elements compared to the 2xII, and there's not enough space at the back of the rear element to accept the protrusion of the 1.4x TC. 

Note that you can stack a 1.4xIII and a 2xII - the limitation is for the 2xIII.

ah woops i didnt know the mk2s could be I wonder why they killed that ability on the mk3

also I would expect having so many connecting interfaces in the optical line there is more room for off centered focus due to construction tolerances on each mounting point.

Overall I dont think stacked TC is very practical due to massive AF slowdown and quite a big IQ hit
maybe if you are shooting something totally static it might be ok but not if you intend tracking anything
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