Originally Posted by Fiat131
Thank you very much for the explanation.
Do you think it would help first (before hitting the record button) to point to the sky and slowly move the camera down towards building, while still showing the sky?
I'm thinking, if that would help, while the camera is in "Auto" mode.
Would ND filter do anything helpful in such situation?
Possibly not, if you expose for the sky, then the darker areas would become under exposed and very dark or black. This is where dynamic range kicks in, the camera can only capture a limited extreme of dark or bright with the same exposure setting. Something has to go out of range when you have very bright and dark areas in the picture.
Remapping values above 235 gets a bit more dynamic range, but even then that may not always help.
The professional way is to use a graduated ND filter, this filter is shaded at the top and clear towards the bottom (similar to half tinted sunglasses), so the sky is darkened and bringing it into range to allow the whole frame to be captured without blowing the highlights. You often see this on some lower budget TV programs or news reports where they've added a graduated ND filter but then decide they need to pan. The shaded area becomes visible as the picture changes.
Sometimes you need a matte box to make these sorts of graduated filters work well, and they only work on shots where the frame is split cleanly across the horizontal so sky at the top and landscape at the bottom. It has to be a steady or a tripod shot as movement will make the filter become visible as the line between shaded and unshaded will not move with the image.
Other ways are to brighten the subject or the shadows using reflectors and/or lighting.
However these techniques don't lend themselves to our domestic use of camcorders, so it is case of avoiding such scenes, letting the highlights blow out, or dealing with in post.
An ordinary ND filter will not help as the whole frame is affected, the sky becomes less dark, but the shadows become darker so you still have the same difference between light and dark.
Another option that can help with blue sky at certain times of the day is a polarising filter, as this will darken the sky without darkening other parts of the image, helping to stop the sky being blown out.