>>3390375>warm-moist breathFun fact: Condensation adheres to the grease on a lens not the glass. If you breath on a clean lens the condensation should clear almost instantly. I gently blow on a lens to test it.
>risking any of the microfibre cloths or glass cleaner fluidAs long as you don't go wild with the fluid and keep the cloth clean they save a lot of time. Microfibre is magic for cleaning glass (but can trap grit), cotton tends to smear the gease about. I only use fliud on used lenses or after an accident.
People worry too much about about lenses (the glass). If the wind slaps a dead wet leaf on your front element give it a quick clean with your t shirt and carry on shooting. The auto focus and stabilization is far more delicate than the coatings on the glass.
tl;dr only clean lenses when you NEED to.
