Hi JB,
I just left a long reply at the 645z FB group. The short answer is that IT2 is just the pipeline to bring the image to the computer. Then you use LR or C1 or whatever to display it. IT2 lets you pick what folder you send the files to, and then you make that a 'watched' folder for auto import in your processor software.
The best workflow is to send Large, 1* jepgs, and write the RAWs to the camera. If you just want to see what you're shooting as you go, this is a good solution. C1 actually displays the Jpegs slightly faster than LR, ironically, but can only do RAWS with a 3rd Party hack, and then they look like shit. Phocus works too with the jpegs, if you happen to have a copy.
This is how I work (with LR). I import the Raws afterwards, and LR matches them up to the jpegs and I edit from there.
It works just fine. I hope LR does native tether support soon. The reason it's slower than native phase or hassy tether is because of some internal processing by the 645z that i can't get to stop. That adds about 3.5 seconds. Actual transfer is virtually instantaneous (since it's USB3).
Let us know if you have questions.
- N.