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

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Offline ewavr

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now we have the extended range on 8 different cameras.
the a570 seems to be done as well, but either fudgey or ewavr need to check it into svn.

s5is is also ready, but not tested  :(

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Offline PhyrePhoX

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well, at least one version of the a570 was reported ok by fudgey. i guess you can check em in, people will come and whine here anyway in case it doesnt work ;)
you could add the url of this thread to the committ message?

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MrSpoon

Hmm, I found this: http://pdf1.alldatasheet.com/datasheet-pdf/view/130796/ROHM/BD3916FVM.html
I am a really n00b at electronics, so probably I am missing something, but shouldn't the VDD be still on if  E21_LATCH is off? Otherwise, what's the point of VCC2_DET2?

I don't know much about CCDs etc but from the datasheet the STB pin (connected to the E21LAT net) will immediately turn off the negative rail (REG2 connected to VL). The internal circuitry of the BD3916FVM shows that STB only affects the REG2 amp and not the REG1 amp...so E12LAT only affects VL and not VDD imo.

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Offline quietschi

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Hi
long exposure for ixus70_sd1000, tested works for 102a.
attached patch against trunk 735 for all platformsub (stubs_auto.s not included) and testbuilds for 100c and 101b
cheers quietschi


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Offline quietschi

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here testbuild for ixus70_sd1000 102a

Hi all!

According to changelog.txt in s2is-100e-0.9.8-735 build, extra long exposures should work for all cameras? If that's correct it doesn't work por s2is.

If I am wrong sorry for the post.


Sorry I miss information, the doesn't work means that max exposure time remains 64 seconds

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Offline PhyrePhoX

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sorry to tell you this, you are wrong, it doesnt mean that it is enabled for all cameras. s2is remains to be "unlocked".

quietschi i guess we can also check your patch in, i mean, if you found the adresses in a legitimate way and did not just "guess" them ;)


The firmware of my Ixus950 (and I believe all other cameras with the same sensor -- A720, S5, Ixus80 to name a few) contains an interesting piece of code VsubCont.c, called from ImageSensorTask. The name immediately raises suspicion, as it reminds the mnemonics of Substrate Voltage Control in some CCD chips. The function (located at FF9B9C3C in my case) writes to three hardware ports (CCD voltage control??), 0xC022009C, 0xC0F18010, and 0xC0220090. Calling it with allowed parameters 1,2,4,8 doesn't produce anything spectacular -- just changing the live image brightness a bit. But does it actually change CCD voltages, and if so, which ones? The best way to find out would be to hook up a voltmeter to the sensor pins while writing to these ports -- but this requires opening up the cam, which I don't like. I thought you might have already taken one apart.


I remember on CCD webcams, if you reduced the voltage a bit, the image brightness was slightly darker. And when I was experimenting with the amp-off on my A530, I remember the same thing happened. If you further reduce the voltage, there's a point where the image gets black and some weird horizontal lines.

On A530, the CCD feeds from a voltage multiplier at some 13V. If the voltage multiplier is software-controllable we're right on track. At 10V (already out of specs) you still get images, but darker. My amp off reduces the voltage at some 6V, where you get nothing in live preview. The idea is to decrease the voltage inmediately when the exposure begins, and RESTORE the original volts before the exposure finishes, else you get a black image and maybe some white lines. If you decrease the volts even lower than 6V, there's a point where the CCD "turns off" and you might get nothing, even after restoring the original volts before the CCD readout.

I also remember on the Reflex 300D, it has a pin to control the CCD glow directly. Check: http://glogg.jupiter-io.net/300D/amp_off/amp-off.asp and also http://glogg.jupiter-io.net/300D/

Regards!

PS: my friends tried out long exposures with sucess on A570, works!
« Last Edit: 17 / April / 2009, 01:48:36 by Leonardo Miguel Delgado »

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Offline mngc

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Hi,

Extra long exposures extreme interesting for me. My camera is a590is FW 1.0.1b.
I tested the 735 autobuild, only max. 64sec selectable.
Possibly this new feature add for this camera? I want to use for astro photography, Thanks.

 

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