LensRentals Blog: A Look at Electromagnetic Focusing

From LensRentals Blog:

If you’re like me you like to know what’s going on inside your camera or lens to some degree. They are tools, and if I want to get the best use out of my tool I need to know it’s strengths and weaknesses.

You may not have noticed, especially if you shoot just Canon or Nikon, but there’s been a quiet change in autofocus motors going on. Or you might have barely noticed marketing-fluff terms like ‘linear focusing’ or ‘electromagnetic focusing’ without really understanding what they meant. Even if you understood the general terms, you probably aren’t really certain how they work, or how they might be better or worse than what we’ve been using.

So I thought some of you might like taking a look into what might (or might not) be a big deal: the changes that are being made in autofocus motors. Today I’m going to discuss linear electromagnetic focusing motors. I may do another post about linear-piezo and ring-to-linear piezo motors later, but those are, so far, less common than the electromagnetic motors.