I have recently tried to do some low light shots using long times (for example 15 seconds). and i have found out that sometimes dngs are NOT saved when using times longer than 2 seconds. The card is a fast 32 gb sandisk uhs1.
Card type and speed is completely irrelevant.
Thank you for the reply. Ok, so it's not the card.
CHDK decides whether or not to save raw based on some CHDK settings (like "raw exceptions", "only first raw in series" etc) and camera mode (for example, some low light/high iso modes don't produce valid raw data). There is nothing that depends directly on exposure speed.
Ok, and i have checked, there aren't exceptions: raw should be always saved.
It's also possible that the Canon code takes a different path that doesn't hit the raw hook under some circumstances. This should be repeatable if the conditions are identical. If you can narrow it down to some repeatable set of settings, that would be helpful.
Finally, there is a shortcut to toggle raw on and off, which you may hit inadvertently. On your camera this is probably trigger by pressing the 'disp' button in alt mode.
I'm sure i haven't pressed disp in alt mode.
Let's start from certain things:
i have tried to shot the same thing in M mode, 2second delay, starting from 1/500 to 5 second i have the raw, at 15 seconds there isn't a raw file. If you want exif data i'll upload them somewhere.
Turned off the camera.
Then i have retried 15 seconds, 2 seconds delay, and i have a raw (?)
So tried with tv bracketing +-1 1/3 around 15 seconds... custom delay 3seconds and 3 shots and:
- i don't have a raw for the first shot (15 seconds)
- i have raws for the second (exif indicates 15seconds but it's brighter) and the third (6 seconds) shot.
Thank you in advance.