R5 lunar photography with stacked EF extenders

Bigger wrote:

Leeuw wrote:

Bigger wrote:

Leeuw wrote:

Canon’s 2x ii extender can be stacked with the type iii extenders. Having 2x ii, 2x iii and 1,4x iii gives me several options to combine with my EF 600 f/4 II and R5.
This thread inspires me to start some experiments. For instance how would the 2x + 2x double stack perform. Maybe a bridge too far but why not give it a try.

What I have found from my terrestrial testing is that the EF 600 f/4 II definitely benefits from a 2x converter, even on a 5DsR with 4um pixels. The added 1.4x seems to help a little, especially on an R5, but I don't think there is any resolution left to get beyond that with ~4um pixels. The 2x + 2x might help with an R6 or other ~6um pixel camera, though.

Thanks, I will definitely try the 2x + 1.4x stack and see if the 2x + 2x does add something but probably not. Maybe a 8K video image stack can extract some extra details…..

The image stacking doesn't do much to increase B&W detail--it mostly helps with color detail by filling in the missing color sub-pixel info. That's not much help for lunar photography since the subject is B&W (but it will help keep it that way by reducing false color).

Don’t rule out seeing effects (air turbulences) with these magnifications and subjects at infinity. Smart stacking uses the best frames and even best parts of each frame providing more detail and less noise. For planetary and solar imaging I have used the 600mm with 1.4x extender plus 5x Barlow with great details but only after stacking many frames. A single frame hardly shows any detail.

Extra focal length is good when the lens (or telescope) has more resolution than the sensor. But once the lens becomes the limiting factor, additional FL doesn't help resolve more detail, it just magnifies and multiplies the aberrations.

Sure. But the EF 600mm has proven to me to have a surplus of resolution and can be extended a whole lot I'll give the 2x double stack combined with avi stack a try without expectations.