Dear Pentax
.
Some criticize K-7 and other cameras for Dark Frame Subtraction (DFS) during extremely long exposures (1/2 hour and longer). Effectively, DFS shortens the night by half.
What if it were possible to pre-perform the DFS exposure say by opening the shutter for an hour and saving a special DFS image file every 10 minutes. Then, during the actual shoot the photographer wouldn't have to wait for DFS, but rather camera will take the ready image from the card. The pre-shoot DFS exposure could be an option from the camera menu that will greatly improve the usability of the camera. The regular DFS can be retained of course.