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]

I also have a bad back, so I can relate to those related issues. 

Stacking extenders is inadvisable, IMHO.  The expected gains do not support the means.  Download the manual and do a search for “lens groups” for a detailed explanation of how extenders and specific lenses work with your camera.

I understand that you are manual focusing, but your image quality will take a major hit.  There is no substitute for having actual focal length in your lens.

[ebiggs1]

"Stacking extenders is inadvisable, IMHO."

Mine too, in fact any 2x tel-con is not a good idea, IMHO. It is a fool's errand to spend your limited funds this way. Don't do it. Have you looked into a t-mount and a t-mount to Canon for your telescope? Way less than a single 2x te-con even a used one.

[Waddizzle]

Another issue with using 2x extenders is that you may get “ERROE 01” messages with certain lenses, Exp specially if you begin to stack them.

Again, there is no substitute for have a lens with the actual focal length you want or need.  

Teleconverters are not cheap.  Only certain models will work with certain combos of camera and lens.  That is why I suggested that you download the manual and search for “lens groups”.

[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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If your screen is black, then you need to enable ExpSIM in the camera.

[Tronhard]

I suspect that the reason it's not working for viewing through the live view compared to the viewfinder is that one sees the image via the viewfinder with the aperture wide open, which is not how the image will be captured.  Live view reads the image off the sensor with the aperture closed down.

My research indicates that the minimum f/stop with the 100-400L on the 6D is f/8.  Each 2x extender added will cost 2 stops.  So, with 2, 2x extenders that gives f/8 - f/11  - f/16 - f/22 - f/32!  When looking at an essentially black universe at f/32 it's going to be black! So, to try to get a decent exposure one would have to crank up both the ISO and extend the shutter speed to a period where I would predict there is almost certain to be movement of the earth, resulting in star trails.  That isn't even addressing the significant impact on the image from diffraction.

I am not an astro photographer, so if someone here is, can they confirm or correct this logic please?

[Starlight90]

I don't use tel-con, I use the official canon 2x extenders. These are stackable. I won't use cheap knock offs unless they are recommended. 

The tel-cons aren't compatible with L series lens

[Starlight90]

I got no error code message. I use the official canon L series extenders

[Starlight90]

I have a printed manual for my camera 

[Starlight90]

Thank you for all your replies, I shall go through each and everyone of them properly and determine my options. 

However, the equipment I currently own, none of it is cheap. But if I need to sell it all off to afford the better equipment. Then so be it. 

[Tronhard]

I sympathize with your predicament.  I really, really wish we could come up with some solution to your desire to use multiple extenders, but in all honesty, I see it as an investment that will not provide the results you want and will be a frustrating and costly effort.
Astro is a fairly specialized activity, and if you actually have the specific optic but need the adapter, then that would at least make use of your investment.  If this is something you want to specialize in, and are prepared to relinquish other equipment for the right gear, that seems like a more sound proposal.

I really wish you all the best with this and hope you get a satisfactory outcome.