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

fe50

PhyrePhoX
ewavr, it doesnt seem to work on the s3is. 60 seconds - ok. 70 seconds and longer - not ok.
behaviour: when i set 70 seconds, and do a halfpress, the cam already shows 15", so it DOES notice the longer shutter. when i then press fully it takes a picture, but only with a very short duration. now here is the catch - the picture is very dark, so the real shutter that was used must be very short. BUT when i view this image in playmode, camera tells me it was shot with a 15" exposure.

The same on the SX10 - 65s is ok, 66s takes a picture with minimum shutter speed, no crash...

@ewavr, the asm magician: absolutely 😎

ewavr

fe50
The same on the SX10 - 65s is ok, 66s takes a picture with minimum shutter speed, no crash...

Oops! The same thing on A710, when I downloaded CHDK from autobuild server. When I compliled CHDK yourself, it works as expected (gcc 3.4.6) (you can download version for S3 and SX10 from http://ewavr.nm.ru/chdk/for_test/) .

Now I try to find this bug (BTW, which GCC version uses autobuild server?).

edit: Maybe source is CPU registers corruption in apex2us()

PhyrePhoX

i will test and report.

btw "show build info" tells you that the server uses gcc 4.3.2.
really weird.

edit: works. tested 100 seconds, works like a charm. yay \o/

ewavr

Silly error.
Must be fixed in #729.
Tested on GCC 3.4.6 and 4.3.2 for a710.

edit: I tested autobuild #729 - works fine on a710.

ewavr

fudgey
a570 100e works fine for me already.

With sources from reply #27 or #28?

fe50

ewavr
Must be fixed in #729.
Tested on GCC 3.4.6 and 4.3.2 for a710.
edit: I tested autobuild #729 - works fine on a710.

Nice 😀
I'll test it this evening when i'm back...

PhyrePhoX

i won't even try it, as i know it works when ewavr is committed to something 😀

fe50

@PhP:

PhyrePhoX
i won't even try it, as i know it works when ewavr is committed to something 😀

[right]LOL - i know this, so therefore i said [tt]...I'll test it...[/tt]
I never TRY to do something, i just DO it (and maybe fail) or DO it NOT 😎BTW: we have full moon, so you know what this mean to me - running thru the woods tonight, the tests have to wait 😛[/right]

http://www.youtube.com/watch?v=sQghSEl0hHQ       (SA - full moon, vampire/manga version)

fe50

ewavr
edit: I tested autobuild #729 - works fine on a710.

Success (autobuild #729) also on the SX10, works great - as expected 😀

barret

So, maybe it's time for Camera Features Chart update? 😁
http://chdk.wikia.com/wiki/CameraFeatures

fudgey

ewavr

fudgey
a570 100e works fine for me already.

With sources from reply #27 or #28?

#28 should be ok, I checked your fixes from my disassembly and they seemed correct.

For a570 100e diffs in #27 and #28 are the same now actually since I edited it after you posted the fixes. For 101a there's one difference (you forgot to list one more fix you made "BL sub_ffebcfbc\n" -> "BL sub_ffd0e5d4\n", about 10 lines from "loc_ffd20fa0:\n" forward.

ewavr

esu
What should I do to make this work in a S5 IS?

Please test - http://ewavr.nm.ru/chdk/for_test/

2 moderators: I propose to split this topic, because long exposures and modding on a A530 very different things.

edit: also for a550 - the same link.

ewavr

[unknown]
quick question: what is the maximum exposure time now with this new feature?

We must make some experiments to answer this question.
IMO, it limited by battery life time and image quality.

barret

how can i set those long exposure times? i cannot set it through 'extra photo operations' menu... max. is 64 sec.

thanks ewavr 😀

Set Shutterspeed enum type = factor
then set "override shutter speed" and "value factor"

update: it works!!! thank you ewavr!!! 😁
on canon a550:
100 sec. works!
300 sec. works!
600 sec. works!
1200 sec. works!!!
although image quality (noise) is quite bad. how can we fight it?

ewavr

barret
although image quality (noise) is quite bad. how can we fight it?

See https://chdk.setepontos.com/d/3409 😁

**Made an Amp-off circuit to control the CCD voltage during the exposure. This is to avoid the CCD glow at the corners of the image.
**Peltier cooling to reduce hot pixels and slightly increasing the sensitivity.

barret

See https://chdk.setepontos.com/d/3409 Big Grin

oh, yes, thank you, i've read that before 😁 interesting work, but rather extreme, don't you think? 😁

ewavr

Without hardware modding we can only:
- use dark frame subtraction
- use noise reduction software
- use RAW sum (not average) of shorter exposures

or buy DSLR with big sensor 😉

fudgey

I haven't done many test shots, but one 10 minute exposure with ISO80 F/11 (that aperture was to get rid of light, F2.6 got me severe overexposure in moonlight) was actually pretty good after Canon's dark frame removal. There was some noticeable noise in the top left corner where amp glow is the worst, but the photo is completely usable when scaled down a bit.

On the other hand, shots that long taken inside in poor light look very bad.

gremmy

I was just wondering if there's a chance that an extended exposure time for the a590 might be available soon. Thanks to all the developers working on this, it really is great.

barret

i would like to thank all the developers for this great work!

anyway, i still have some questions:

**Made an Amp-off circuit to control the CCD voltage during the exposure. This is to avoid the CCD glow at the corners of the image.

Is it technically possible to turn off this amp thing not in hardware but in software?

**Peltier cooling to reduce hot pixels and slightly increasing the sensitivity.

so, i assume that in winter, when temperature drops at night, my night shots should be a bit better in terms of noise levels/quality?

greets

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