Photographing behind dirty screen
Before yesterday's experience I was afraid of dirty screen. I think it is a nightmare. Therefore I have never took picture behind a dirty screen, I'm afraid that I'll have a ruined image.
Yesterday tried to took picture of my office car's very dirty wind screen from inside the car. I accidentally focus the camera to the object far from the camera. It is amazing that the dirt on the wind screen did not appear on my image.
The conclusion is: dirty glass screen can be defeated, I don't have worry anymore.
This is how to do it:
This is the picture of my office car's windscreen. I think it is very dirty.
On the second picture, you can see that all clear. This picture was taken on the same car as the first picture. You can't see that it was taken behind a dirty windscreen, since there is no dirt on the picture.
However I did not recommend people to take photograph behind dirty screen. Always move to find other position with unobstructed view. Use this way as the last resort!
I recommend you to clean your windscreen due to driving with dirty windscreen is dangerous!
When this trick does not work
When there is strong sunshine the dirt will become ghosts that appears on the image.
However the most important lesson I learn today is:
if you have something that worry you, you should try to find trick around it. In order to find the trick, you must experiment!