According to DB <db002a3121@blueyonder.co.uk>:

    O.K.  I don't know the DX 50 -- is this a new version of the
D50?

    In any case -- plain auto exposure will probably work, but not
TTL auto exposure -- because of differences in reflectivity and
diffusion between film and the sensors.  TTL depends on light bounced
off the film, and even a camera like the NC2000e/c (Nikon N90s with a
digital back from Kodak) won't work with the TTL metering for that
reason. Nikon did not even *try* to make it work with their DSLRs.
Instead, they have a new system, which uses a pre-flash for metering
just before the actual exposure to control how much the flash unit needs
to put out before quenching the flash.  (IIRC, Nikon called this new
system ITTL).

    Another consideration (and the one which relates to the possible
damage) is the voltage present at the flash sync contacts.  IIRC, the
D70 specifies a maximum voltage of 250V positive, or *any* negative
voltage without damage to the camera's flash sync circuitry.  If you
have a voltmeter, you should verify what the flash unit places on the
sync terminals.  You will probably also need an adaptor to provide a PC
contact, unless your flash units have a flash shoe which is compatible
with the Nikon ones.

    Good Luck,
        DoN.