How does the vertical sync frequency vary with the requested frame rate of the FLIR A615/A655?

The native frame rate of the FLIR A615/A655 is 50 Hz and the vertical sync output is also 50 Hz. If a lower frame rate is requested, the vertical sync frequency will remain at 50 Hz. However, if windowing is used, i.e., with frame rates of 100 and 200 Hz, the vertical sync frequency will also be 100 and 200 Hz, respectively.