Opto-mechanical design of lenses requires the integration of optical design with good mechanical practices and system considerations. The correct approach to the design is a comprehensive specification encompassing all the important parameters for the specific application. Items influencing the designer are scheduling, personnel availability, design costs, specification realism and perceived marketplace requirements. The two most important inputs to the design process are a comprehensive performance specification and a definition of imposed constraints.
The performance specification defines the application and how the lens will operate, while the constraints must be detailed and include the followings:
Performance requirements
Optical
- F/N                              - Magnification
- Wavelength range      - Focal length
- Iris requirement          - Focus requirement
- Distortion                    - Resolution
- Vignetting                   - Working distance
- Object size                  - Sensor size

Mechanical and general constrains
- Size, shape and weight limitations
- Special optical thin film coating needs
- Interfaces (optical, mechanical, electronic, etc.)
- Operating environment (temperature, pressure, humidity, vibration, etc.)
- Loads (static and dynamic)
- Center of gravity
- Material selection limitations
- Finish/color requirements
- Special marketing or identification
- Storage, packing and shipping requirements

Once these parameters have been carefully reviewed and any compromises agreed to, a final design and proposal is completed and work commenced. Following are a list of definitions that are important in describing optical specifications.