I have a problem with a pair of Zeiss Victory HT last week when out stalking I picked up a roe buck with the thermal in some cover and checked it with the glass but couldnt see it so glass down and recheck with thermal still there but had moved and was easier to see back to the binos slight adjustment to focus and got ready to take the shot and of course it moved again and i couldnt see it so back to the thermal to confirm it was still there it was and was moving slowly out of cover so back to the binos and it was visible but out of focus reset focus and back on the rifle with 8x56 swaro quick check with binos and they were out of focus the deer then decided it liked the look of something tastier and cleared of i cant understand why just by lowering slowly and then picking them back up within seconds should alter focus any ideas will be appreciated