Despite the 'impossibility' of focussing 'accurately' by eye in the digital age, I am one of many, many photographers who still use a groundglass and shoot digital - shock, horror - despite what Alpa, Arca etc. say concerning the ability to focus accurately in this day and age. And guess what, my images are tack sharp. When the debate 'raged' some years ago about shimming, I honestly thought photography had been lost for good to the bean counters, retired engineers and IT guys seeking a second career.
Both Arca and Alpa's approaches to accurate focussing are fine as long as the distance is recorded on the little card (Arca), or on the HPF ring (Alpa). If not, then what do you do - make an educated guess? Precision has become a very useful marketing tool - I mean, no one is going to argue that a system should be less accurate are they? Why is it Alpa won't produce a sliding back (too 'inaccurate') but Arca and others do, with great success?
This is all rather moot to be honest, especially if you tilt the lens. Then focus becomes the means to tilt the plane of focus, and to be in absolute control of that you need to use those two things either side of your nose (hint: not your ears, nostrils, eyelids or eyebrows).
Both Arca and Alpa's approaches to accurate focussing are fine as long as the distance is recorded on the little card (Arca), or on the HPF ring (Alpa). If not, then what do you do - make an educated guess? Precision has become a very useful marketing tool - I mean, no one is going to argue that a system should be less accurate are they? Why is it Alpa won't produce a sliding back (too 'inaccurate') but Arca and others do, with great success?
This is all rather moot to be honest, especially if you tilt the lens. Then focus becomes the means to tilt the plane of focus, and to be in absolute control of that you need to use those two things either side of your nose (hint: not your ears, nostrils, eyelids or eyebrows).