Question about using a heat gun on lens elements

I was softening old adhesive on a 50mm f/1.8 in my shop in Austin and saw a tiny hairline crack form in the glass. Has anyone else had this happen with a specific temp setting?

3 comments

3 Comments

beth_anderson2mo ago

Oh man, that sounds rough... but is it actually in the light path? Sometimes those tiny cracks are just in the edge glass and won't show up in your photos at all. I'd slap it back together and run some test shots before calling it a total loss. Heat and glass can be a nasty combo, maybe try a lower temp next time... if there is a next time.

webb.stella2mo ago

Beth_anderson makes a good point about checking if it's actually in the light path. It reminds me of how we often assume the worst damage right away. I've done that with a phone screen protector, thinking a huge scratch ruined it, but it was just on the edge and never bothered me again. We jump to the total loss conclusion before even testing the thing.

mila_jones3912d ago

Wait, did you try shining a light through the glass to check the crack? I cracked my old 50mm lens once, and I was so sure it was ruined, but it turned out the crack was just on the outer ring, not the actual element... Never showed up in any photos, even in bright sunlight. I'd definitely run some test shots before giving up, maybe even shoot against a white wall at f/22 to really see if anything's off.