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

reyalp

3belas
update : 512 sec is working.

i wonder how long actually it can go and whether is save or not to use it

This has been asked earlier in the thread, and the consensus is, we don't know 😀

Which canon firmware is your 590 ?

edit:
From a code testing point of view, if 128 sec works then the change is working.

edit again:
I see 101b in the other thread. As soon as someone verifies 100e, I can check this in.

mngc

Now the medium test on a590is, fw 1.0.1b

Extra long exposure working, but have some problems.

16,32,64,128,256 sec ok.

But 3belas, 512 sec NOT ok. Recording time ok, 512 second (i disabled the dark frame subtraction, to speeedup the test). My original goal the picture quality check (noise, hot pixel, etc.). Lower exposures correct, the image bright and brighter. But with 512 sec the image black. Totaly black, i check with picture viewer, RGB= 0,0,0. I use 230Volt adapter for power the camera.

Test around 512sec:
322sec OK
406sec OK
420sec OK, enum type changed
440sec OK, enum type changed
450sec OK, enum type changed
470sec X , enum type changed
512sec X
645sec X

reyalp

Camera limit maybe, nothing in our override code knows the difference between 470 and 512.

mngc

For another cameras users with extra long exposures (not a590is fw 1.0.1b) ok with 512 sec?

@3belas, your 512sec picture totally black or no?

reyalp
Camera limit maybe, nothing in our override code knows the difference between 470 and 512.

fudgey

mngc
For another cameras users with extra long exposures (not a590is fw 1.0.1b) ok with 512 sec?

I believe I tested my a570 100e up to 600 seconds (worked fine, DFR enabled if I'm not mistaken).

mngc

fudgey

I believe I tested my a570 100e up to 600 seconds (worked fine, DFR enabled if I'm not mistaken).

Thanks, your test. I not understand "DFR enabled" what is this?

@reyalp

I think the camera has a second software or hardware timer with unkown fuction, which is kill the real picture, and somehow fill image with zero. Main cycle, the recording time always ok, i try enable dark frame subsraction with 512s. The time is ok, 512 * 2sec. But picture again fully black. Any information on hardware available (shematics, chip datasheet, or chip type?). I have knowledge to electronics. You can attach the software patch? I interest. (please note, i am not expert in assembly, and CHDK). How the patch working (simplified)? Canon has a hardware or software timer, and check or count timer owerflow(s)?

460s working properly, this is great. The picture is noisy and have many hot pixels. This is normal, with extra large exposure time and small CCD sensor. This is not fatal error. Requies many set of picture and averaging it. And requies a master dark frame (average set of dark frame). CHDK has function to record set of dark frames without normal picture? Or options to create two picture (one normal picture, and one dark frame)? Hardware way to record dark frame, the lens cap, and record normal picture. But the optical mechanics i think very soft.

reyalp

mngc

fudgey

I believe I tested my a570 100e up to 600 seconds (worked fine, DFR enabled if I'm not mistaken).

Thanks, your test. I not understand "DFR enabled" what is this?

@reyalp

I think the camera has a second software or hardware timer with unkown fuction, which is kill the real picture, and somehow fill image with zero. Main cycle, the recording time always ok, i try enable dark frame subsraction with 512s. The time is ok, 512 * 2sec. But picture again fully black. Any information on hardware available (shematics, chip datasheet, or chip type?). I have knowledge to electronics. You can attach the software patch? I interest. (please note, i am not expert in assembly, and CHDK). How the patch working (simplified)? Canon has a hardware or software timer, and check or count timer owerflow(s)?

We basically just override the function that sets exposure time. To do this, we have to hook expdrvtask and copy the code up to the point where we change it (apex2us)

patch http://www.zshare.net/download/612200006af1558d/

CHDK doesn't let you create dark frame directly. This can be done, but it hasn't been implemented in CHDK. Cover the camera or use a blacked out box, bag etc.

yvesson

Hej,
Would it be possible to record the pic before the dark frame is taken, mostly for testing purposes ?

Just curious, why 10 min exposure (with prolly very bad results) could be usefull ?

reyalp

yvesson
Hej,
Would it be possible to record the pic before the dark frame is taken, mostly for testing purposes ?

Yes, I implemented this (a540 only) a long time ago. https://chdk.setepontos.com/d/1998

mngc

yvesson

Just curious, why 10 min exposure (with prolly very bad results) could be usefull ?

You are correct. 460 sec = 7.66Min exposure not too good, but not too bad. My goal the astro photgraphy with wide/normal/tele angle zoom, circle picture /point of Polaris star/, and software mixed lots of picture, and automated (?) meteor shower (meteors randomly with time) photograpy. I know various problem possibly, long test requied, to best result/time, picture piece, settings, and of course the real sky/. Now i in large city, this is worng for astro photography, night city light very bright. The CCD temperature important to noise ratio in long exposure. High temperaure = high noise, low temperature = low noise. But not all noise from temperature problem. With CHDK i see the temperature, great! For example CCD amplifier own noise... The final test requies dark sky and low temperature night, and of course equatorial mount with electronic drive. I know large CCD cameras are better than this equpment, peltier cooling more better, and infrared mod useful, for example Canon 300/350D. And special expensive CCD cameras too. But not have it, and too no have chdk, i think.

mngc

@reyalp

Thanks the source, hard work, i see!

Good news, the dark frame set possibly in future. 😀 Master dark better, than one dark with lower exposure times too. CHDK has raw average, good function!

CHDK has a badpixel removal option, i can create badpixel bin with lua script. But i not know this badpixel information where from. The script takes picture, this is a dark or not dark picture, the scene (blue sky, or anyting, and settings important? Or this informations from canon firrmare ROM, etc.? Or this is equal the "light frame" in astrophotography corrections?

yvesson

reyalp

yvesson
Hej,
Would it be possible to record the pic before the dark frame is taken, mostly for testing purposes ?

Yes, I implemented this (a540 only) a long time ago. https://chdk.setepontos.com/d/1998

Hej,
Thanks for refreshing, I had missed that one. Luckily for me, we have the same cam. ^^

3belas

mngc
For another cameras users with extra long exposures (not a590is fw 1.0.1b) ok with 512 sec?

@3belas, your 512sec picture totally black or no?

I shot at the same setting and light condition and as a result, i got different pictures with difference lightness (exposure)..So i thought it was working.. No, my picture is not totally black..maybe i was mistaken (set it to different exposure, not 512 but 256..

my A590 is 101b

reyalp

mngc
CHDK has a badpixel removal option, i can create badpixel bin with lua script. But i not know this badpixel information where from. The script takes picture, this is a dark or not dark picture, the scene (blue sky, or anyting, and settings important? Or this informations from canon firrmare ROM, etc.? Or this is equal the "light frame" in astrophotography corrections?

The badpixel file is a list of the pixels the canon firmware sets to zero rather than blacklevel. These are interpolated over when dng is made. DNG spec requires this.

The reason a list is used is because scanning the entire raw buffer for zero pixels would be slow.

This isn't really correct, because the canon firmware does different things at different exposures.

If you use CHDK raw instead of DNG, it's ignored.

There is a second bad pixel system for user specified bad pixel lists: http://chdk.wikia.com/wiki/Badpixel_removal

ewavr

reyalp
The reason a list is used is because scanning the entire raw buffer for zero pixels would be slow.
This isn't really correct, because the canon firmware does different things at different exposures.

But pixel from list is interpolated, if it is really bad (in patch_bad_pixels_b() function):

if (get_raw_pixel(ptr[0], ptr[1])==0) patch_bad_pixel(ptr[0], ptr[1]);

yvesson

Hej,
Just tested 1024s on my A540, and I got a 17min exposure pic, looking bad especially that I didn't let it substract a dark frame, would have been just too long. But now I wanna try again with the dark frame on, afterall, I'll host the pics somewhere and show the results here.

ravelithium

reyalp

The Long Exposure for A560 work perfectly, (64 to 2040s).
As soon as possible I'll up some work to my
http://ravelithium.deviantart.com/
Thank you a lot ^^

fudgey

I guess this
https://chdk.setepontos.com/d/3461/84
deserves a bump.

I see two downloads, no test reports for the a650.

h-v-n

Big request do extra long exposures for a630

mlietchnyipout

Hi! ^.^

I see SD850 (IXUS 950) is working with extra long exposures in "Camera Features" -> http://chdk.wikia.com/wiki/CameraFeatures
And I see in the "Changeset 734" what there's a patch for the build 100c -> http://tools.assembla.com/chdk/changeset/734

So, is it possible to use this build on a SD870 (IXUS 860) ? (it's the same build; 100c)
If yes, where can I find this new build?

Thanks -.^

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