Because of the low resolution that has tradtionally been available, the operator has been prone to under reporting of the dew point, because by the time condensation had accumulated enough to be visible, the dew point had already been reached and passed.
Because of the low resolution that has tradtionally been available, the operator has been prone to under report the dew point, in other words, to report the dew point temperature as being below what it actually is. This is due to the fact that by the time condensation had accumulated enough to be visible, the dew point had already been reached and passed.