Canon extender 2x mk ll on Canon 6D produces black images - SOLVED

[Starlight90]

Hello everyone,

I have a Canon 6D camera and 2 2x mk ll EF extenders (canon official), I have read that you can stack these extenders and get a bigger and better view of an object.

The Lens I'm working with is a  canon EF 100-400mm f/4.5-5.6 L IS USM Lens with the 2 extenders, however my live view doesn't with them both attached to my camera and lens, but I can see through the view finder, after I've taken some photos of the moon just to test and observe, I go back to check to see how they came out, it's all black, like nothing was taken, just a black void.

Can anyone advise?

Thanks 

[Waddizzle]

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@Starlight90 wrote:

Hello everyone,

I have a Canon 6D camera and 2 2x mk ll EF extenders, I have read that you can stack these extenders and get a bigger and better view of an object.

The Lens I'm working with is a  canon EF 100-400mm f/4.5-5.6 L IS USM Lens with the 2 extenders, however my live view doesn't with them both attached to my camera and lens, but I can see through the view finder, after I've taken some photos of the moon just to test and observe, I go back to check to see how they came out, it's all black, like nothing was taken, just a black void.

Can anyone advise?

Thanks 

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Where have you read this?  Please post a link so we can review it.  THX!

If you have not already downloaded a copy of the User Manual, then I suggest that you use this link.  Download the PDF and search for phrase “lens groups”.

https://www.usa.canon.com/support/p/eos-6d 

[Starlight90]

Hi and thanks for your reply. I own a physical manual.

I was also told by my local camera shop in Chester, Wilkinson camera here in England as well.

These are the sites:

https://www.quora.com/Can-I-attach-more-than-one-teleconverters-to-achieve-4x-or-8x-or-more-magnific....

https://www.dpreview.com/forums/thread/3710997

[Tronhard]

Hi and welcome to the forum:
I'm not sure where you go this information from but the suggestion that one can get ' bigger and better' images does not fit conventional wisdom or experience, especially for any extender before the MkIII models.

There are serious issues with extenders working with the focus and apertures of different models of cameras - only certain bodies will support autofocus and autoexposure - in fact most extenders require a f/stop of f/8 and single point focus (if at all) and that is for most bodies with the MkIII (much improved extenders). 

However leaving that aside, there is always a cost to adding an extender to any lens.   Any 1.4x will cost at least one f/stop of light, while a 2.0x extender will cost two stops, and inevitably adding more lenses into the focal path will downgrade the image.  Adding two extenders would result in a serious degradation of image, and cost at least 3 stops, but likely 4 stops - which translates 1/16 (2 to the power of 4) of the light transmission almost certainly resulting in diffraction issues.  Furthermore, adding a lot of mechanical joints will degrade any weather sealing integrity of the camera and lens and likely slow down lens response even more than one.

I have shot with the MkIII versions of both 1.4x and 2.0 extenders, and would definitely recommend getting a lens that is built for the job.  Adding two 2x extenders would provide a focal length of equivalent of 800-1600mm, and with that magnification and low light transmission, one would have to have the camera on a tripod.

[Starlight90]

Thanks for your reply, I don't use the auto focus on my lens, I always use manual focus, as I find it easier to control. 

I know that with each extender, you do loose light, obviously depending on which extender that is use, as you have said. 

As far as I am aware, you cannot stack mk lll extenders without an extension tube. Unfortunately I cannot afford the mk lll and the mk ll were both in my price range £140 each, where as the mk lll is £220 each as the lowest price. 

[Tronhard]

I am curious why you need the focal lengths you are seeking - up to 1600mm FL.   It would be a false saving to get gear that will seriously degrade your images just to get extra FL.

[Starlight90]

Mostly for planetary photography and moon photography. At 800mm it's just not big enough, the bigger lenses are at least £5k plus and are way out of my range, and at the moment I'm unable to get the correct equipment for my skywatcher telescope, again, out of my price range. 

So this is my best option at the moment. 

[Tronhard]

I would strongly suggest trying before you commit yourself. Astro will require relatively fast lenses to avoid tracking marks.

Have you considered shooting in APS-C mode to give you a 1.6 boost in Field of View.

Can you not get some kind of astro telescope to which you can fit an adapter?

[Starlight90]

My sky watcher is an astro telescope, I just can't afford the adaptors and due to muscle damage I can't lift it.

I used to do astro photography at high school with their dslr 20 years ago. 

[Tronhard]

If you are determined to invest your limited funds, then that is your choice. If it were me, I would save up for the right gear. But it's your decision and your money.