Originally posted by RaduA In all honesty I don't get it how you could "guesstimate" the center and border resolution of the DA* 55 wide open from some low res samples (kindly provided by TKH
You're right, I was guesstimating. Here is how I did it:
I took the very first image of this thread (TKH's image of DA*55 at f/1.4). It is
significantly softer than the same image at f/1.8 -- at the low resolution of 1200x800.
If it appears to be soft at 800 pixel height, it will
not have a resolution very much in excess of 1200 LW/PH (at f/1.4). Which is a value only "fair" to "good". Not on par with the "very good" of the Sigma. More like the FA43, which is "good/very good" in the center and "poor" in the borders (fully open). Eventually, I concluded the border resolution won't exceed the center resolution
Anything wrong with my method? It was the best I could do before we get resolution measurements from test charts. Of course, I assumed that TKH has hit precise focus.