Can I correct the focus on the FaceTime camera of an Apple Thunderbolt Display or iMac?

I have long used a Thunderbolt Display with various MacBook Pros. (Although old, heavy, and not retina resolution, its decent size, integrated camera, high quality speakers and simple connection to the MBP continue to make it a solid choice after all of these years.)

I recently inherited a second Thunderbolt Display when a friend was getting rid of his, and I wanted to set it up in a second office. However, I noticed that the output from the built-in FaceTime camera is blurry at close distances (such as sitting at the desk at about 18-24" away from the screen, as normal). I have checked that the glass is not dirty, and the blurriness is consistent using different applications, different user accounts, and even using different MacBook Pros. Items 8-10 feet (2.5-3 meters) away seem to be in focus (or, as in focus as you could expect with the 720p camera).

Is there a way to calibrate the focus on the camera on this display?

Searching the web, I found this post, in which one user disassembled the display and physically rotated the camera on its board, and I might try that if it comes to it, but I'd ideally like something that doesn't involve disassembly!

If anyone has had a similar experience with correcting the focus of an iMac's FaceTime camera, that might be relevant as well.

Thanks in advance.