Richardman,
John is right, that's the first thing to make sure that the lens can reach focus at infinity.
Then, no laser rangefinder and no HPF ring can be of help, if your OWN back is not calibrated itself with the camera used. There are samples variations, with each DB, in terms of position of the sensor, despite what one may expect from a DB costing that much. And those tolerances are not little, a few 1/100th to the 1/10th of mm, which has huge consequences on the real position of the focus when measured with a laser or set with an HPF ring, backwards or in the front.
This becomes even more important, when focusing in a close range or in macro setups.
That can be corrected by a shimming, and it must be corrected, otherwise it doesn't make any sense to have the most precise and resolving back, lens and camera, when one link is broken in the chain. Even more so with the latest generation of DBs with their small pixel pitch.
It is not especially a pride, of having a camera allowing to do that, it is a must, IMO.
Best regards
Thierry
The Alpa prides itself on being able to shim the back to precisely match the camera.
How important is that if you are using hyperfocal distance or guesstimating your focusing? (rather than say using the IQ in liveview, or a laser rangefinder and the high precision focus ring)?
Thanks.