technique - What combination of camera, teleconverter, image stacking, or sharpness increase will best improve my moon photographs?

I'm trying to improve my moon shots.

I'm currently shooting it with a Canon EF100-400mm f/4.5-5.6 USM lens mounted either on a Canon 450D or a Canon 6D.

I realized that my Canon 6D gets me fantastic results but the moon is too small. I can crop nicely but it has its limits.

On the other hand, the 450D gives me less sharp results but the moon is bigger. Of course, I cannot crop much because it's quickly messy.

I've read about teleconverter and the fact they decrease sharpness. Buying a 2x is out of question because of the quality loss but I'm questioning myself on the 1.4x.

More specifically, the question I'm asking myself is :

What would be the better setup to get a nice shot of the moon ?

• Canon 6D, Canon 100-400L, increase sharpness through Lightroom



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  Canon 4506D, Canon 100-400L, increase sharpness through Lightroom

  
  


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  Canon 6D, Canon 100-400L, image stack up

  
  


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  Canon 450D, Canon 100-400L, image stack up

  
  


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  Canon 6D, Canon 100-400L, 1.4x teleconverter, increase sharpness through Lightroom

  
  


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  Canon 450D, Canon 100-400L, 1.4x teleconverter, increase sharpness through Lightroom

  
  


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  Canon 6D, Canon 100-400L, 1.4x teleconverter, image stack up

  
  


• Canon 450D, Canon 100-400L, 1.4x teleconverter, image stack up

Do you guys have experience in that field ? Have you already tried one or more of those combos ? Is there a much better way to improve my shots ?

P.s. I know shooting the moon with landscape would be better, my whole point here is only to get a moon as big and sharp as possible.

Samples (both processed with Lightroom only) :

Canon 6D : https://500px.com/photo/116560719/madam-by-andy-m?from=user_library

Canon 450D : https://500px.com/photo/117058521/orange-madam-by-andy-m?from=user_library

Answer

I'm not a moon photographer, but your examples are just about as impressive as I've seen taken with a DSLR and standard camera lens. Some of the things you're looking at may help, but I think they're just going to be incremental. Additional sharpening is only going to get you so much, and the teleconverter is only giving you a less-than-50% increase in each dimension, and stacking can give you more detail but ultimately not something anyone will notice from across the room.

To really take things to the next level — which I think is where you want to go, especially since you mention that you just want moon images, not landscapes-with-moon — I think what you want is a telescope. Mount your camera to that with a "t-ring adapter". See How do I choose a telescope for space and planets photography? and How to shoot images from a home telescope using a digital SLR? for your next steps.