So - the GT-2...
in the hand it is compact and not too heavy; solid enough to give an impression of quality. The front filter size is 62mm which makes it large but not unwieldy when mounted to the GRIIIx using the GA-2. The camera senses when the lens is mounted so there are no settings to change. There are no do's and don'ts in the leaflet in the box but if you try to set the lens to macro with the GT-2 mounted it objects strongly and shuts down. The lens is weighty enough to necessitate a 2-handed grip when in use - not a bad thing, I think.
In terms of output, I went to visit my old friend The Angel of Lens Testing today. As always, I stood in the same place, used the same settings (f2.8 throughout) and focussed on the face. Conditions were overcast.
These are the results:
First, a straight reference shot for comparison purposes - 40mm native, yielding a 13mb, 4000x6000 file.
View attachment 283583
Next, the 71mm digital zoom setting. This is a 4.02mb 2240x3360 file
View attachment 283584
This is the 40mm setting plus the GT-2. File now is 6.9mb, 3200x4800
View attachment 283587
Finally, the 71mm digital zoom plus the GT-2. This is 3.57mb and 2240x3360
View attachment 283588
I shall leave you to draw your own conclusions from the images shown; for me the increase in bokeh between the digital and optical is noticeable and pleasant. At full stretch, with the digital and optical combined it is still impressive but I see a softness creeping in on the Angel's features. The GT-2 also appears to lose a little contrast, especially compared to the "bare" lens at 40mm.
Overall, it's a keeper. I'm seriously considering snagging a secondhand GW-4 now to go on my GRIII; I feel like I am back in GXR days, in a good way, with a much better body and a less - outre...? - lens system.
EDIT: Interesting to see what the forum software does with the lens EXIF; it doesn't recognise the digital zoom "focal length" but it does the physical GT-2