live bulb - Feature Requests - CHDK Forum  

live bulb

  • 1 Replies
live bulb
« on: 10 / September / 2013, 08:45:13 »

This is a feature implemented in some "expert" cams nowadays, called "live bulb":
during long exposures, and especially bulb time, one can see the image building up on screen and check when it is appropriate to (forcibly) end the exposure.
I didn't have one in hand, so I suppose the image on screen is refreshed every 5 ou 10 seconds.

I don't know whether it's feasible on our powershots, but it would be a nice-to-have thing  :)

PS: sorry if already posted, I used search but not 100% sure of negative result :-/
SX110IS + Barn door tracker = Astrophotographer

Re: live bulb
« Reply #1 on: 10 / September / 2013, 16:28:17 »
Unfortunatelly cheap Cannon P&S cameras have very limited memory. Due to that when camera exposures picture it uses the same memory which is usually used for displaying image and user interface. This is why all that things disappear while taking exposure and LCD screan blacks out.

So there's no way that CHDK coul display anything during the exposure. Moreover - once camera goes into the exposure CHDK loses control until the exposure is end.

One thing that could be walk-around is to shoot multiple images with RAW and then stack them one by one until you get the exposure you need. But this is problematic when there is some move in the frame - like stars, cars, lights.
if (2*b || !2*b) {

Compile error: poor Yorick


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