The standard OS200 does not have a built-in tool for measuring field curvature.

However, it is still possible to construct a manual plot of field curvature using the OS200. The digital micrometer is used to measure image shift at multiple field positions.

When using the nodal slide, the microscope remains parallel to the chief ray. This complicates the geometry by introducing a 1/cos term. Contact WRD for a sample Excel spreadsheet which shows how to compensate for this effect.

Field curvature can also be measured with the optional off-axis collimator mount.