How do I stop my glasses fogging up while deer stalking?

I am assuming the condensation is on the outside of your glasses. Since the arrival of nitrogen-filled scopes, it is has been a very long time since internal fogging has been an issue.

Personally I can’t actually remember having any trouble with lenses misting up when out deer stalking, so if it did happen it can’t have made much of an impression at the time!

A slow routine

This might be due to my routine which is to get out of the car, assemble my gear and then sit on the tailgate to have a cup of tea. So possibly the condensation problem had disappeared by the time I was ready to go?

Furthermore, having a slow and settled starting routine like this also gives the woods time to settle down again after your arrival.

So why does condensation happen?

If you take something from warm to cold, the warmer air on the lens surfaces gives out moisture as it cools, creating a mist which needs to be wiped.

When the warm surface cools to the air temperature, condensation usually stops. It is irritating but this happens with scopes, binoculars and also, of course, with spectacles if you wear them.

I have heard of cloths and sprays which are supposed to prevent condensation, but not seeing it as anything other than a brief inconvenience, I have never tried them.

Anybody else have any suggestions?