night sky timelapse video with shutter speed override

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164

Re: night sky timelapse video with shutter speed override

« Reply #30 on: 05 / May / 2008, 23:23:30 »

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Quote from: mcx on 05 / May / 2008, 12:19:42

Well i can't say it 100% correct, but i took a shower while the picture was made. ...

So here it is:
my picture

...

MCX,

I forgot to add, the bluish/purplish area in the upper left and corner is probably "Amp Noise" (amplifier) that gets worse as the chip gets warm (not hot--just warmer).

There is nothing wrong with the camera or damage being caused... This is the type of noise that NR (dark frame subtraction) is supposed to take care of.

-Bill

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mcx

16

Re: night sky timelapse video with shutter speed override

« Reply #31 on: 06 / May / 2008, 17:01:06 »

thanks

i will test it tomorrow... i think, and then i'll post the next picture

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fuzzychicken

5

Re: night sky timelapse video with shutter speed override

« Reply #32 on: 10 / May / 2008, 03:02:00 »

Quote from: chuckheron on 19 / February / 2008, 15:08:03

I created a Long Exposure Intervalometer page on the wiki: UBASIC/Scripts:Long Exposure Intervalometer - CHDK Wiki
(not as fancy as the Shutter Speed Stack, but it gets the job done..)

Here are some of the timelapses I've done as well:
chuckheron wiki / TimeLapse

-chuck

I plan to use your script but my issue is same as yours, auto exposure, as you have already mentioned on the script page. I am curious to know if you plan to update this script with Auto Exposure setting. I am not remotely geeky (i don't even understand the script) so I can not modify it myself. But if you do implement, I would certainly like to give a try.

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mcx

16

Re: night sky timelapse video with shutter speed override

« Reply #33 on: 10 / May / 2008, 09:26:13 »

you were right guys. last night i took a picture with NR setting 2. It is darker than the last one, but the time was different than last time and aperture was now F5 (last time F2.8). But it has absolutely no hot pixels or anything like that:

i will test some other with brighter settings...

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jetzt

316
[A710IS,(SD200)]

Re: night sky timelapse video with shutter speed override

« Reply #34 on: 10 / May / 2008, 13:59:48 »

Hi,
I have also experimented with long time exposures,
the worst thing with canon in camera NR is that a ~ 64 sec exposure takes about TWICE as long as without.
So here are my attempts to reduce that time ...

(again)[fight against]noise in long exposures or about almost "bulb mode"

Nice results anyway, I like your script so far!
Interesting that there are others trying that

.

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mcx

16

Re: night sky timelapse video with shutter speed override

« Reply #35 on: 10 / May / 2008, 14:06:04 »

well you're right. i took a darkframe and subtracted it from the old and noisy picture too, but the darkframe seems to change from time to time. the result of subtracting the 2 frames manually wasn't as perfect as my last picture with the in-camera NR so i think i wouldn't take a "template-darkframe" and then always subtract it from the long exposure-pictures...

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jetzt

316
[A710IS,(SD200)]

Re: night sky timelapse video with shutter speed override

« Reply #36 on: 10 / May / 2008, 14:31:03 »

Yes, I didn't try for a few weeks now, but I'll handle it like that:
1)If only 1 picture or gap between shots unimportant use camera nr
2)If several shots have to be taken first take shots and then darkframe, when camera is "warm"

I didn't really test if turning IS off is useful. But unlike others I don't think so.

Have fun shooting,
jetzt

« Last Edit: 10 / May / 2008, 14:32:35 by jetzt »

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mcx

16

Re: night sky timelapse video with shutter speed override

« Reply #37 on: 10 / May / 2008, 20:47:21 »

i'll maybe test it if i take more shots.. but you're right, the time would be much shorter...

here is now again a picture at night... NR 2 and aperture F2.8:

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