Images, and the devices that capture them, are my focus. I've covered cameras at PCMag for the past 13 years, which has given me a front row seat for the DSLR to mirrorless transition, the ...

Place those lenses in a tube and voilà ... Galileo played with this formula until, by the late fall of 1609, he'd made a spyglass that could magnify what is seen by 20 times.

Smaller numbers mean more light in this instance, with a logarithmic scale based on the square root of 2, a mathematical oddity dictated by the circular nature of a lens and the formula to ...