The film itself has some issues and I'd be shocked if anyone ends up actually seeing it, but I'd be remiss not to mention that Masanobu Takayanagi's work on Hostiles might just be my favorite of the year. Epic yet intimate, sumptuous yet gritty. It really has it all. It's a shame the film that surrounds it is so comparatively lackluster.

Yes - like any digital sensor, the Helium gains exposure latitude in the highlights as you increase ISO, and loses latitude in the shadows. Between 800ISO and 1600ISO the DR will "shift" towards the highlights by one stop. The Alexa does this as well - exposure latitude extends to being able to retain +6 stops overexposure in highlights at 1600ISO, up of +5 at 800!

I completely agree - after we started the test we realized how much it would have been nice to also include a Dragon in the mix as well, to really demonstrate how the Helium differs from it, since all of us have shot on the Dragon before and were relatively familiar with what it was capable of doing. Next time!

Sort of -- but you'd only be able to notice a marginal difference. And even when looking at the images in their full size on your laptop, you won't be able to really see it. You need to see them in a larger venue to discern the difference.

This would have been the ideal set-up, yes, but unfortunately we didn't have time to shoot each lighting set-up separately on both cameras with different ISO's, so settled on one for simplicity.

That said, this is actually slightly incorrect logic. ISO doesn't work like a film stock - it's actually all relative. Both cameras' real ISO's is somewhere way lower - 400, 800, 1280, 1600... these are all varying degrees of artificial digital signal boosting in order for the sensor to be able to record more light. They're all relative.

And the "base ISO" of both cameras - 800 and 1280 - is relative as well: these are just the ISO's at which the dynamic range of the sensor is most evenly distributed in both the shadow and highlight range, from middle gray, and so is just the "ideal" ISO in order to capture the maximum range of tonality in the highlights and shadows.

Changing the ISO on either camera doesn't actually affect the DR - all it does is "shift" the Dynamic Range either towards the shadow region (if you lower ISO) or towards the highlight region (if you raise it). That's all it would do.

Dave, check out my comment above to Nakean about perceived resolution.

As for dynamic range, Arri underreports its DR - advertises as 14 stops when really it's more like 15. RED advertises Helium as 16+ stops, but that is inaccurate.