A Condensation Tip
I'm not sure if its been posted here in the past, I just wanted to share my recent experience with my Tamron 17-50 with a cheap UV filter for safety.
We went outdoors and the temperature was below 50 F, clicked many pics and rushed to some restaurant for some coffee. While having coffee I noticed the condensation on the UV filter attached to my Tamron. I removed the UV filter to check the front element/group. Only UV filter got the condensation but the lens was safe. I cleaned the filter and re-attached it and my Tammy was back in action.
It only happened while my Tamron was on, didn't test it with other glasses I have. Please have a rice bag handy if you wanna test this on your glasses.