EXHIBIT 4.10

                                               May 7, 1999


Attn:  Christopher Ricci
Focus Enhancements, Inc.
600 North Road
Wilmington, MA 01887

Re:      Union Atlantic LC ("Union Atlantic")/Focus Enhancements, Inc. ("Focus")
         Agreement

Dear Chris:

         Per your  request,  I am writing to  document  our  understanding  with
respect  to  the   above-captioned   agreement   dated  December  12,  1998,  as
subsequently amended (the "Agreement"). The terms of the Agreement require Union
Atlantic to have an exclusive  relationship  with Focus for six months, or until
June 12, 1999, solely with respect to the sale of substantially all of the stock
or assets of Focus.  With respect to a minority equity  investment in Focus, the
relationship is non-exclusive.

         With  particular   regard  to  Focus'   relationship  with  JW  Genesis
Securities,  Inc.  ("JWG"),  it is agreed that the commissions  described in the
Agreement  shall be waived for any placement  through JWG.  Union  Atlantic will
seek  cash   compensation   for  any  such   transaction   directly   from  JWG.
Notwithstanding the foregoing,  upon closing of an equity placement through JWG,
Focus shall  issue to Union  Atlantic a purchase  warrant  for 25,000  shares of
Focus  common  stock at a per share  exercise  price not to exceed the per share
exercise  price of the  warrants  granted  to JWG/or the  equity  investor  with
respect to the subject equity investment.

         Should you have any question, please don't hesitate to call.

                                         Respectfully,

                                         /s/ Leonard Sokolow

                                         Leonard Sokolow
                                         Partner