My Laowa 25mm 2.5->5x ring light gets very hot. I am wondering if anyone knows whether this could damage the lens in some way. Perhaps this could affect internal adhesives or lubricant or whatever. I only use it for reference when setting up front/back values for a stackshot rail, so it's not like I have it on all the time. I have taken to scotch taping conical bit of paper to it (which makes a nice diffuser). So far that has not caught fire, but touching the ring light after it's been on for 5 minutes is very uncomfortable. The front element is very close to that ring light.
Have questions about the equipment used for macro- or micro- photography? Post those questions in this forum.