Dirty And Wet
I knew there was going to be a problem as soon as I put the camera to my eye. A raindrop on my sensor.
I’d been careful switching lenses under the shelter of my trunk as I’ve done so many times before. There is always the danger of dust getting on the sensor and frequently does. It is usually easily removed with a Giotti blower. A raindrop is a different animal.
The only way to remove it is with a cleaner swab which I don’t carry in my bag. The required liquid has a low evaporation point and wouldn’t survive even moderate temperatures in the car.