This is not unique to Canon, but there is no third-party lens forum, so here goes.
I recently bought the Tamron 150-600 G2 with the Tamron Tap-in Console for $1099 from BuyDig. My camera body is a 7DII. I already had the Sigma USB Dock, which I used on a prime lens. Using either of these on a prime lens is pretty straightforward. However, when I started to figure out adjustment values for the G2, things got hairy. First, the Tamron console allows focus adjustment for 18 combinations of focus distance and focal length with this lens (3 distances x six focal lengths). I was trying to figure ballpark adjustment numbers by using the Dot-Tune method at each focal length/distance combination. However, this required me to choose between making adjustments in the camera at the wide end versus the long end. I figured that at 150mm the wide end made sense, and that at 600mm the long end would make sense, but what about the other focal lengths? It turns out that you do not get the same results with Dot-Tune when you separately adjust the wide end and the long end by the same amount. What to do at the four focal lengths between 150 and 600? Then there is the issue of whether in-camera adjustment values correspond to the values used by either of these lens systems.
Dustin Abbot used the Tamron console to adjust a prime lens (the 45mm, perhaps?), and used values from FoCal. However, I doubt that the FoCal target would work at the distances required for the G2 (2.2m, 20m and infinity). FoCal expects the target to be a certain distance that is a function of the focal length, not independent of the focal length, as these devices require.
The one sure way to use the Tamron console to adjust the G2 seems impractical to me. It would involve arbitrarily setting an adjustment for a single focal length/focus distance combination using the console. Then you remove the console, put the lens on the camera, and take a series of test shots at that particular FL/distance combination. You then put the lens back on the console, change the adjustment, take the lens off the console, and shoot some more tests at that FL/distance combination. You then compare the two sets of shots, and based on that comparison, try another adjustment setting, comparing those shots to the best of the first two sets. And so on until you find the optimal setting for that FL/distance combination. Keep in mind that there are 41 possible adjustment levels. Then you repeat the process for the remaining 17 combinations of FL and distance.
This seems daunting to me. So, has anyone used either of these devices to adjust focus on a zoom lens, and what was your procedure? Tamron only states that these adjustments are possible, not how they should be done.
(BTW, the lens itself is quite sharp and focuses well without adjustment. It's just that the console came with the lens, and I figured I would use it. Now I am determined to figure out if there is some practical way to do so.)