3) One aggravation using the HC adapter: one has to focus wide open and at relatively high ISO (indoors) to see focus accurately and then stop down (and lower the ISO) to take the shot. There's no automatic "focus wide open but shoot stopped down" mechanism, making the lens cumbersome and slow to shoot indoors. My awesome dealer investigated this and spoke to Fuji directly, who confirmed the lack of automatic stop down shooting, but said that the firmware was finished just prior to shipping and that he expects there to be a number of (unspecified) functional upgrades to the adapter with subsequent firmware revisions from Fuji--so we can, at least, hope.d
4) With the Hassy adapter and any other manual lens adapter, one has to turn off both the preview WB/exposure and the companion preview picture settings. The GFX EVF will gain up (indoors it can become very, very grainy) and this helps focusing to some extent. You'll need to read EV values to understand your true exposure and adjust aperture/ISO/SS accordingly. In many cases, even turning off both picture preview settings isn't enough--I find turning up ISO, focusing and then turning down ISO, while cumbersome, works fairly well and my hit rate is quite good. As I already noted, there is no "focus wide open," "shoot stopped down" function yet for the Hassy adapter. Using flash indoors requires exactly the same discipline. So far, when lowering ISO after obtaining focus, both the Fuji 500 and the Nissan 60A flashes have worked flawlessly to correct the exposure. And both work quite well up to 1/800 with the Hassy adapter.