Hello Luong,
Glad that at least one person found this article interesting.
I mostly agree with you, scanning back are very tempting beasts. However:
- The price you quote seems a bit optimistic to me. What I would consider buying is one of the latest USB + sensor II models, and these cost about 12.000 US$ new, and are difficult to find on ebay (plus the sellers appears to be limiting them to US buyers for some weird reason...),
- From what I read, the limitations of scanning backs are even greater than those of stitching. A subject can move when you stitch, it just shouldn't be near the overlapping area, if it is, the movement should be steady (water fall at low speed for instance). Correct me if I wrong, but any movement in the scene with scanning will result in RGB artifacts, right?
Buy yes, otherwise it is indeed much more pleasant to be able to compose an image on a LF camera GG... no doubt whatsoever! Shooting LF film is of course something I still do, but the cost is high, and there is no histogram display built in the Provia 100F quickloads is there...
As far as DoF goes, you are totally correct. However one advantage of shooting digital is that you can do DoF stack up first (assemble 2 or 3 images shot at different focussing distance), and then stitch the resulting images... although this can become really a pain and requires a lot of rigour! Not easy to do in even slightly changing conditions, or when you are excited with this amazing scene that you might never see again...
Cheers,
Bernard