RF Native Lens Cropped vs 1.4x vs 2x

[Fast Glass]

For sure. I understand what you are saying. But I think the premise of gaining light is where you are confusing things. Cropping doesn't lose exposure but raises noise to the point where using a higher ISO would achieve the same end result noise wise.

I think it is useful to know what it does with higher ISO's. And I agree it is 100% relevant. You'll know how far you can push your settings.

I like to isolate things like sharpness in this instance and let ISO fall where it may. Whether it is ISO 12800 or 400. I'll just know for myself what ever ISO I am using, I'm still pulling the most detail I can. Because if we shoot even higher ISO's, we can render these differences moot. So while it is useful to know what it does at higher ISO's. It doesn't replace or very good at figuring out is it better to use an extender or not from a detail resolving standpoint.

Basause if it is sharper/pulling in more overall detail with a 2x, there is no reason to crop. Because if I crop by 2x, I'm gonna reveal the same amount in noise as if I used an extender and used 2 stops higher ISO. At least in theory. There could be other sensor tech stuff happening that I don't know about. I am no Daniel Browning. Haha.

But if cropping is actually sharper, then regardless of the ISO it will be the better option. But so far it seems that the 2x is still relevant.

When I get home, just for giggles I'll do the same post processing with the 1.4x and covert to Jpeg. The RAW preview doesn't tell all.