extra long exposures (split from: Hardcore modding on a A530, thanks to CHDK!

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Offline an0n

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Here's a list of all cameras with the long exposure feature: http://chdk.wikia.com/wiki/User:Fe50#long_exposures

Thaannkkyou ! have been waiting for that. (For user guide).
Will some nice developer do it for A720, please. :D
A720IS.

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Offline yvesson

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  • A540 SX10IS
    • poll about some pics (not much serious) ^^

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Offline mngc

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  • a590is fw 1.0.1b & sx110is fw 1.0b
Some questions, i try generate a master dark and the master flat to process the long exposures pictures.
How many gray depth bit in raw file? 8-10-12-14? And this camera what type CCD used? Datasheet for CCD available? For example, real size of one ccd pixel in micrometers?

The bit depth of compact raw files is normally 10 bits. Don't have information on pixel size or the sensor make available. What are these needed for?


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Offline reyalp

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The bit depth of compact raw files is normally 10 bits. Don't have information on pixel size or the sensor make available. What are these needed for?
Newer cameras are 12 bpp, although the actual precision appears to still be 10 bits.
Don't forget what the H stands for.

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Offline mngc

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  • a590is fw 1.0.1b & sx110is fw 1.0b
This parameters requied for astro photography. I create a flat field, for correct vignetting and dust or pixel intesity problem. The best flat filed picture average intesity is half per full expusured pixel. But requied the raw pixel information, the own camera processed image file not same instensty.  For example, canon EOS 350d has a 14bit = 4096max., some astronomical processing software save this in 16bit, but only 0-4095 informative. For this (EOS) camera the best raw average intensity is 2048.

CHDK has a function to found statistic information for raw picture?

Pixel size is important to astro photography, lots of program use this paramater. For example, with real focus lenght with REAL pixel size, the resolution in arcsec, easy find. And the field of view too, horizontal, vertical, and full.  The sensor size not too good, normal CCD has specially used pixel, etc. but the sensor size in mm?

The bit depth of compact raw files is normally 10 bits. Don't have information on pixel size or the sensor make available. What are these needed for?

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Offline mngc

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  • a590is fw 1.0.1b & sx110is fw 1.0b
Newer cameras are 12 bpp, although the actual precision appears to still be 10 bits.

I confused. For a590is 10bit raw is correct? Or use 12 or 16? bit file format, with 10bit real pixel information?

Very good, free, but very difficult program (mostly command line) to  process astro images.
http://www.astrosurf.com/buil/us/iris/iris.htm

Graphical alternative, free, easy, but the result not the best.
http://deepskystacker.free.fr/english/index.html

Booth program used own(or adopted) raw converter, to best result. Raw conversion important to picture quality.

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Offline reyalp

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I confused. For a590is 10bit raw is correct? Or use 12 or 16? bit file format, with 10bit real pixel information?
The a590 is 10bpp. You can find this information in the CHDK source http://tools.assembla.com/chdk/browser/trunk/include/camera.h
Don't forget what the H stands for.


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Offline RaduP

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Re: extra long exposures (split from: Hardcore modding on a A530, thanks to CHDK!
« Reply #158 on: 05 / September / 2009, 13:13:20 »
Well, I tried the extra long exposure on my A570is last night, full moon and stuff.
Here is a 256 seconds exposure: Moonlit flowers
And a 645 seconds one: Moonlit flowers

So thanks everyone who added this, it's a really great feature, and I wonder why Canon didn't add it in the first place.

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Offline RaduP

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Re: extra long exposures (split from: Hardcore modding on a A530, thanks to CHDK!
« Reply #159 on: 06 / September / 2009, 01:41:49 »
Ok, I think I found a bug :/
On my a570is, for really long exposures (over 2700 seconds, possibly less) the camera will freeze with a blank screen. No buttons work, including the power button.
Can someone please confirm this?

 

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