You don't know what you're focussing on, you kind of have to estimate and use your eyes. I have found that if I am shooting with the lens at a low f stop as in wide open, that I am usually quite close to something so I can focus using the spot meter/focus mode and be OK but also use the viewfinder if I am concerned about what is in the frame. For landscapes or people that are further away, I would not usually have the lens at such a low f stop and thus the depth of field is greater...so again, even if I use the spot meter, I still can bring the camera to my eye with the viewfinder and all will still be well. Does that make sense? I think using the depth of field calculator and factoring in the X1's crop factor which is apparently 1.5 can help if one is mathematically inclined. There is a thread over on L. Camera where this is discussed:
X1 + external viewfinder: any best practices? - Leica User Forum you can probably get more out of it by reading it there where one member has linked to a pdf file that has to do with depth of field, too. I believe it's in this same thread that it's mentioned that one person has had the center point for focussing etched on his viewfinder's glass.
I tend to use the viewfinder when I can't see too well (either too dark or too bright) and then depending upon the f stop, I'm usually not too worried. It is different from the good old Olympus EVF, that is for sure.
Anyway, onwards and upwards as they say!
