The new Sony NEX-5 digital still camera makes an excellent director’s finder. It has an APS-C sensor that is almost identical to Super 35 format: (23.4 x 15 mm), has an accommodating 18 mm flange focal depth, and no mirror to get in the way of PL motion picture lenses. You can order the PL to E mount adaptor from Mike Tapa of MTF Services, and from ZGC in the US. You can also order Canon, Nikon, Leica, and many other E mount adaptors as well.
Quick setup: Push the MENU button at the back. Select SHOOT MODE, MANUAL EXPOSURE. Set the iris on the lens. Then, rotate the jog wheel of the NEX-5 to adjust shutter speed. (There’s a helpful EV “lightmeter” displayed on the viewing screen.)
Pushing the MF FOCUS ASSIST button toggles a digital zoom of 14x and 7x for critical focus. Push the MENU/EXIT button to get back to normal viewing.
To see how sharp the new Leica Summilux-C is, click on the image below of Bob Primes, ASC. Every hair is defined, perhaps suggesting a new standard in lens evaluation: whisker pairs per millimeter.