In manufacturing and research, "6.5" often refers to the or zoom ratio of an objective lens, paired with a digital camera system.
Located in Arizona, the Multiple Mirror Telescope (MMT) features a 6.5-meter mirror designed for both spectroscopy and high-resolution imaging. 6.5 Metre 1080P
Using a 1080P output at this magnification allows for "progressive scan" imaging, which prevents the flickering or blurring often seen in older analog microscope cameras. Summary Comparison In manufacturing and research, "6