Are you concerned about Nikon longterm?

Sony has its own financial issues.  It's had a net loss in the last four years.  “We cannot be optimistic about the electronics business. There are many issues that we need to deal with,” said Masaru Kato, chief financial officer.  They also just sold their NY headquarters building in NYC for $1.1 billion to help add $685 million to their forth quarter.  Sony is in no shape to buy anybody.

Nikon is a company within the Mitsubishi Group of companies.  I doubt it will be up for sale by Mitsubishi.
despite relatively flat revenues.  Canon is not about to buy Nikon either (even if it was for sale.)JPY to ¥224.6B JPYCanon isn't really doing that much better.  It's seen a 2.2% drop in revenues from this time last year. Year after year, Canon Inc. has seen net income shrink from ¥248.6B

The Japanese electronics industry has been quite volatile.  Add the yen exchange issue to the mix, and it's not exactly a stable business right now whether it's Nikon or XYZ Company.