Razor Thin Depth of Field - early 20th century safety razors

Users of this lens are warned in numerous online articles and blogs about the 'razor thin depth of field'. Using f8 in this close-up gave quite a decent depth, although the ISO had to be cranked up to 1000 ISO to give a hand-holdable shutter speed of 1/30 sec.
SMS Pentax-A 50mm f1.7 lens on Pentax K10D.
Picture taken through a shop window at the Black Country Living Museum, Dudley, West Midlands.