R5 lunar photography with stacked EF extenders

Bigger wrote:

Leeuw wrote:

Bigger wrote:

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.

Seeing is an issue, and smart stacking can address that issue, but it can't give the base lens more resolution than it has.

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.

Yes, the EF 600mm II can still alias the center of a siemens star with a 2x iii; but not with a 2x iii + 1.4x iii on a 4um pixel camera, so I think that's past the point of diminishing returns. But by all means try it and see.

Out of a dozen 2.8/400mm lens one had a strehl ratio over 90, most were around 80 and one outlier was a bit over fifty. First class telescopes are in the 95+ range.

So those lenses, exept for the outlier, should benefit from a 2x teleconverter.

Why many photographers fail to get the most out of 2x teleconverters is usually down to atmospheric turbulence (air currents) and sloppy technique.