R5 lunar photography with stacked EF extenders

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).

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.