Nikon Group Companies (Japan only):
Nikon | Company Profile | Nikon Group Companies
Tochigi Nikon Corporation
Main businesses: Manufacture of interchangeable lenses, optical lenses and optical components
Tochigi Nikon Precision Co., Ltd.
Main businesses: Manufacture of devices for semiconductor/FPD lithography systems
Nikon Tec Corporation
Main businesses: Sales of used equipment and maintenance service for semiconductor/FPD lithography systems
Miyagi Nikon Precision Co., Ltd.
Main businesses: Manufacture of devices for FPD/semiconductor lithography systems
Sendai Nikon Corporation
Main businesses: Manufacture of cameras
Nikon Imaging Japan Inc.
Main businesses: Sales and servicing of cameras
Nikon Vision Co., Ltd.
Main businesses: Development, manufacture, sales and servicing of sport optics products
Nikon Instech Co., Ltd.
Main businesses: Sales, maintenance and servicing of microscopes, measuring instruments, X-ray/CT inspection systems, etc.
Nikon CeLL innovation Co., Ltd.
Main businesses: Development, manufacturing and testing services for cell-based therapeutics
Nikon-Trimble Co., Ltd.
Main businesses: Development, manufacture, sales and servicing of surveying instruments
Nikon Engineering Co., Ltd.
Main businesses: Design, manufacture and sales of Projection Exposure System, Live cell Observation System, Laser Marking System, etc.
Hikari Glass Co., Ltd.
Main businesses: Manufacture and sales of optical glass and molded optical glass
Nikon-Essilor Co., Ltd.
Main businesses: Development, manufacture, sales and servicing of ophthalmic lenses
Nikon Lenswear Experience Center Co., Ltd.
Main businesses: Retail sales of ophthalmic frames and lenses
Nikon Business Service Co., Ltd.
Main businesses: Employee welfare activities, procurement, logistics, and activities related to intellectual property
Nikon Staff Service Corporation
Main businesses: Providing staffing and outsourcing services
Nikon Tsubasa Inc.
Main businesses: Processing, assembly and packing of parts for optical instruments
Nikon Systems Inc.
Main businesses: Development and support of computer software
Nikon and Essilor International Joint Research Center Co., Ltd.
Main businesses: Research and Development in materials, optics and ophthalmics
Seems diverse enough to me. Trimming some fat and some consolidation is not going to hurt.