-2 and -1.75 one glass needs 8 cylinders.... and still i have combind glasses with reading inserts.
140 watts TL lighting from different angles helps too, as do the multiple enlarging glasses there are even camera's doing 50x specially for that work, will set me back 150 euro's including monitor on the hamfairs.
Not using one now, still can do the SMD's though, but please don't sneeze....