I wanted to mount a 210 Rodagon on my Durst 183 (5x7 head on 8x10 chassis) with the 3-lens turret. I read about using a camera filter step down adapter (77mm to whatever) and by golly it worked. A 77 to 58 adapter (from $1.22 with shipping on eBay) with a few minutes file work for the 2 edge grooves required and it mounted in the turret and the lens screwed right in. The Durst factory adapter, if you could find one for the 58mm) is mucho buckos.