What do you do when your 100-600mm lens dies and it's not repairable or cost effective to try( no parts )?
You make a loupe out of it. For now it's just the objective lens on the front tube. I will make a new to so that is doesn't neck down. Lens was sitting in drawer for a couple years broken ( electronics ) I was about to toss it out when I decided to pull it apart and keep the glass bits. I looked at the slides on my light table with the objective lens and thought that was pretty sweet, new loupe.
It actually works quite well and is sharp.