SX20IS crashes when high speed shooting - Creative Uses of CHDK - CHDK Forum
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SX20IS crashes when high speed shooting

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Offline muellerdave

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SX20IS crashes when high speed shooting
« on: 30 / October / 2011, 15:55:19 »
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I was messing around with chdk today and tried to do some ultra high speed shots.
aiming for 1/40.000 or more.
i set the camera to manually override the shot setting.
set shutter speed to 1/32.000 left iso and aperture untouched and tried to take the shot.
the camera the just simply turned of.
the lense doesn't retract and nothing. its as if someone pulled the batteries.
i then have to switch it back on and no photos were made.
this doesn't just happen with the extreme high speed shots. sometimes even shots higher than 1/5.000 causes my camera to crash.
any ideas whats going on?
is there a way to record a debug log so you guys can better see whats going on? im sorry im still pretty new to the whole chdk universe.
thanks!
dave
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Offline waterwingz

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Re: SX20IS crashes when high speed shooting
« Reply #1 on: 30 / October / 2011, 16:02:20 »
Hi Dave.   I haven't played with high speed on any of my cameras so I can't help here.  The first step here might be to confirm that other owners of the same camera see the same thing.

Here's a tip though - going forward, its usually better to post this sort of question in the appropriate porting thread - you are more likely to get a response that way.  In this case,  its would be the sx20 porting thread

UPDATE :  apparently not a new problem http://chdk.setepontos.com/index.php?topic=4348.msg51136#msg51136
« Last Edit: 30 / October / 2011, 16:07:20 by waterwingz »
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Ported :   A1200    SD940   G10    Powershot N    G16
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Offline muellerdave

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Re: SX20IS crashes when high speed shooting
« Reply #2 on: 30 / October / 2011, 16:11:12 »
oh thanks mate!
i did a search of the forum but couldn't find that post.
seems to be a pretty old problem that still persists.
kinda strange because it works flawlessly in the other direction. i made shots with exposure time of a couple of minutes and no problems what so ever...
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Offline waterwingz

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Re: SX20IS crashes when high speed shooting
« Reply #3 on: 30 / October / 2011, 16:23:41 »
The Canon firmware might be shutting down when you ask for really high speeds.  There is a script on your SD card in the CHDK/SCRIPTS/TEST directory called romlog.lua that should dump the camera's status if so.

Update :   romlog.lua requires a build with native function call support, which I do not believe is the autobuild default mode.    Try the romlog.bas script instead if the lua version does not work ?

« Last Edit: 30 / October / 2011, 16:25:22 by waterwingz »
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Ported :   A1200    SD940   G10    Powershot N    G16
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Offline muellerdave

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Re: SX20IS crashes when high speed shooting
« Reply #4 on: 30 / October / 2011, 16:37:38 »
the lua script worked.
here is a link to the dumped log:
http://pastebin.com/dFupaaT7
can't make heads nore tails of it :D
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Offline philmoz

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Re: SX20IS crashes when high speed shooting
« Reply #5 on: 30 / October / 2011, 17:21:20 »
Quote from: muellerdave on 30 / October / 2011, 16:37:38
the lua script worked.
here is a link to the dumped log:
http://pastebin.com/dFupaaT7
can't make heads nore tails of it :D

The camera firmware has detected an error condition and has shutdown the camera.
The error is in the shutter code so I suspect that it did a sanity check on the shutter speed you selected and detected it was not valid so shutdown to prevent damage to the camera.

The chance that any P&S camera can actually do 1/40000 second shutter speed is almost non-existent. On other cameras you can request speeds like these; but you don't actually get them.

Try different speed overrides in CHDK to find what the maximum the camera will allow.
Since the shutter is hardware there is little chance CHDK can do anything to change the physical limits.

Phil.
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Offline muellerdave

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Re: SX20IS crashes when high speed shooting
« Reply #6 on: 30 / October / 2011, 17:41:50 »
thanks for your help guys!
sooo basically it seems that the camera is physically only capable of a certain speed and anything higher would break it so it shuts itself off?
messing around a bit i got the camera to shoot photos at 1/10.000 when setting a fixed aperture instead of letting the camera decide on the aperture.
this is still very buggy though. when i change the iso up (left the aperture and speed untouched) it crashed on me again. i then tried it with the exact same setting as before and it crashed again. its about 50/50 if it will work or not.
so it seems like 1/10.000 is the maximum the camera can physically handle. but i would know like to find out why it sometimes works and sometimes doesn't
« Last Edit: 30 / October / 2011, 17:45:08 by muellerdave »
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Offline waterwingz

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Re: SX20IS crashes when high speed shooting
« Reply #7 on: 30 / October / 2011, 17:51:50 »
Quote from: muellerdave on 30 / October / 2011, 17:41:50
sooo basically it seems that the camera is physically only capable of a certain speed and anything higher would break it so it shuts itself off?
messing around a bit i got the camera to shoot photos at 1/10.000 when setting a fixed aperture instead of letting the camera decide on the aperture. amera can physically handle. but i would know like to find out why it sometimes works and sometimes doesn't
How do you know it actually even got to 1/10,000 of a second ?  I have no idea how fast the shutter mechanism can physically move the shutter open and then close but 10 uSec seems awefully fast for a mechanical system.

How did the exposure look ?  Even if you crank the ISO way way up and set max f-stop & no-ND filter, I suspect it would be hard to get enough light for a good picture at that speed ?

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Ported :   A1200    SD940   G10    Powershot N    G16
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Offline muellerdave

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Re: SX20IS crashes when high speed shooting
« Reply #8 on: 30 / October / 2011, 18:03:24 »
light aint the problem.
i can get my hands on some pretty powerfull ones to light up the scene.
but as you said i have no way of knowing what the actual shutter speed is.
i can just say that chdk displaying 1/10.000 is the highest i can see with it still working (now and again)
the really strange thing im still pondering on is why it sometimes works and then 10 seconds later fails to work with the exact same settings...it just feels completely random
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Offline waterwingz

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Re: SX20IS crashes when high speed shooting
« Reply #9 on: 30 / October / 2011, 18:19:16 »
Quote from: muellerdave on 30 / October / 2011, 18:03:24
the really strange thing im still pondering on is why it sometimes works and then 10 seconds later fails to work with the exact same settings...it just feels completely random
When you are working way out on the hairy edge beyond anything the OEM intended the camera to do,  there are lots of things that can go wrong.  This is often a function of timing - things happen in different order internally (race conditions) and will work some times and not others.

For example,  there is a build option for CHDK cameras called CAM_STARTUP_CRASH_FILE_OPEN_FIX that inserts a delay on startup of the CHDK code.  For some reason, it fixes a problem where some cameras would hang on startup - a hang that was random but got worse as more JPG's were added to the SD card.

So,  while you might have found a CHDK bug, more likely you are just a victim of a timing glitch.  Hard to say.

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Ported :   A1200    SD940   G10    Powershot N    G16
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