It's not the lens, it's the sensor that's kept cold- in practice, people taking low-noise shots would use something like this: https://amscope.com/products/mt58

It's not the lens, it's the sensor that's kept cold- in practice, people taking low-noise shots would use something like this: https://amscope.com/products/mt5800-ccd https://amscope.com/products/mt5800-ccd If you put it in a freezer, you can use desiccant or other strategies to avoid moisture-fogging. Or just wait til everything reaches equilibrium?