Oh, an interesting thread that I somehow missed so far
So far, I'm using Linear, and get good results with it. I did, however', also notice that it has a slight tendency to overshoot a tad (by doing another step when I would say it's already at the best position). However, those last steps are (with the latest versions) a quarter of the initial step size.
I did have a look at this NCFZ article. Very informative. Maybe some input here from my side: I used the formula, and my setup and site details, to compute a value of 31μ. My step size of the EAF is 2.8μ, so that is 11 steps. For comparison, my initial step size is 20, i.e., 2 times the NCFZ. In good conditions that allows a very good estimate of the focus from the first pass. I don't think setting the
initial step to 1 NCFZ (or even less) will improve things, and for less good conditions (variable seeing) the (only?) solution anyhow is to do more than one measurement per position, and average.
I do quite sometimes see that the first pass produces an (almost) perfect curve, and then also think 'now you should just go to the computed value, and be done'. Sometimes it's obvious (to me....) that the first pass isn't great, and the second one will improve things. So ideally I'd like to see a combination of both approaches, in finding some criterion on how well the first pass is, and then having an option in Linear to stop after that if it is good enough.
I'm not sure that
always only doing one pass is as stable as the current Linear method.
My current setup will do the first pass in about 11 positions. It typically finishes the whole AF run in 15-20. More only in very variable conditions, but there I wouldn't trust a 1-pass run much, either. This means for me, I could save maybe 1 minute per AF run in good conditions.
I would do rather 'pay' that as an insurance in case of bad conditions. But as you already mentioned in the first post, those that don't have issues with focus as it is can skip.
So my post isn't there to discourage the new method - the contrary! I just thought
maybe my view on this is of some use
I do still wonder why the current Linear isn't working for some, and extremely well for others.....