Big Bend, March 2014
I shot the moon with a borrowed 400mm lens (f/5.6 max. aperture) and a cheap Tamron 1.4x converter. The combination made for a slow f/8, and I also stopped down one (f/11 effective) in attempts to sharpen things up a bit.
I used to own a 400mm lens many years ago, and I'd forgotten how difficult it can be to shoot long. Every bit of disturbance around the camera caused a visible vibration in the viewfinder. Using live view at 10x made the issue very apparent. A cold front had blown through, and the winds were making it impossible to get the camera and lens completely stable.
The other issue with eclipses, and I'd experienced this before when shooting one many years ago, is that the moon gets very dark towards totality. A normal full moon in clear skies is nearly as bright as full daylight. But a moon mostly covered in the Earth's shadow is 5 - 6 stops of light less. That's really challenging when shooting at f/11 :-)