Wow, I would not have expected that.
What sort of flash was this? Xenon flash tube based?
Yup, a Godox V860II speedlite. I’ve popped it at full power against my palm and it feels a little warm for a split second, so it seems like it couldn’t “burn” anything, but the output of light is a lot and it has a fresnel lens that focuses the light further. In hindsight, I’m not surprised at all that it burned the dial and crystal.
Yeah, if you stop to think about it, it’s not surprising, but it wouldn’t have been my first thought on the spur of the moment. Your skin will reflect a lot of light, plus has the ability to disperse a lot of energy without changing temperature much, so it becomes more about total energy delivered rather than peak power. The thin film coatings on the crystal and dial can’t disperse much heat energy, so they’re much more sensitive to peak pulsed power. The flash doesn’t deliver a whole lot of energy total since the pulse is short, but the peak power of that pulse is quite high. Basically, it’s like passing your hand quickly through a flame. You might feel a little warm, but if you’re quick it’s not damaging. But, if you pass a thin bit of paper through the same flame at the same speed, it’s going to burn.
I’m gonna be totally honest and say that it looks very cool, and you have a funny story behind it too!
It looks great, it wouldn’t surprise me if someone does this with a sterile dial some time for a ghost seamaster build.