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Reducing the minimum exposure speed in High-speed Burst HQ mode

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Re: Reducing the minimum exposure speed in High-speed Burst HQ mode
« Reply #50 on: 05 / March / 2014, 09:06:04 »
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2) the Fallback Min Shutter Speed doesn't work as expected: I set it to 1/4s (Min Shutter was at its 1/8 minimum) and then shot a dark scene that would have required at least 1/4s. Instead, 1/8 was used, thus underexposing the picture
3) The same goes for the Fallback ISO setting: although it was set to 3200, no amount of darkness made it go above the ISO400 limit (which is not really a setting anywhere in the menu)
Is this only an issue in burst mode?
Ported :   A1200    SD940   G10    Powershot N    G16

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Offline longtalker

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Re: Reducing the minimum exposure speed in High-speed Burst HQ mode
« Reply #51 on: 05 / March / 2014, 09:38:05 »
In P mode, the ISO goes up to however much is needed to correctly expose the picture, but the exposure still doesnt drop below 1/8. So that way at least you're getting the right exposure, even if you have to pay the price of a higher ISO. In HQ burst mode though, where all these things would come handy, none of the two parameters use the full extent of their allowed ranges (assuming the Fallback Exposure should at laest in theory allow the exposure to drop at 1/4).

Re: Reducing the minimum exposure speed in High-speed Burst HQ mode
« Reply #52 on: 06 / March / 2014, 09:30:21 »
Also, it seems that adding 1/4s to the bottom of the list of possible exposure values (for auto custom ISO) was easy enough - can at least that change be implemented in the stable version, so that it's not limited to 1/8s as the slowest exposure?
In core/autoiso.c the shutter speed array simply does not include 1/2000.
Done : http://chdk.setepontos.com/index.php?topic=650.msg110786;topicseen#msg110786
Ported :   A1200    SD940   G10    Powershot N    G16

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Offline longtalker

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Re: Reducing the minimum exposure speed in High-speed Burst HQ mode
« Reply #53 on: 06 / March / 2014, 09:38:17 »
Great to hear! I'm still not sure, though, how to make sure I'll be able to reuse my settings (which in the meantime I;ve redone manually, for 1.2.0-3367 .. ) in this new version. As I said, copying over the old CFG files seems to do nothing, and the backup script doesn;'t seem to load for me..


Re: Reducing the minimum exposure speed in High-speed Burst HQ mode
« Reply #54 on: 06 / March / 2014, 11:51:09 »
Great to hear! I'm still not sure, though, how to make sure I'll be able to reuse my settings (which in the meantime I;ve redone manually, for 1.2.0-3367 .. ) in this new version. As I said, copying over the old CFG files seems to do nothing, and the backup script doesn;'t seem to load for me..
I just unzip the download file on top of the previous files on my SD card.   Config settings are retained prefectly that way.
Ported :   A1200    SD940   G10    Powershot N    G16

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Offline longtalker

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Re: Reducing the minimum exposure speed in High-speed Burst HQ mode
« Reply #55 on: 07 / March / 2014, 08:13:00 »
Yup, the extra shutter speeds are now there and working as they should.

Thank you so much!

The remaining problem is that the AutoISO in HQ mode doesn't increase to the correct level, at the expense of underexposing the picture. It only does that correctly in P mode. I guess, though, that to make it work well in HQ mode is probably a non-trivial issue, that will take some time to fix.

Either way, the enlargement of the exposure speed range is handy enough on its own. Thank you very much philmoz and waterwingz.

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Offline longtalker

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Re: Reducing the minimum exposure speed in High-speed Burst HQ mode
« Reply #56 on: 07 / March / 2014, 08:23:18 »
An extra observation that might help to fix the problem: the low AutoISO seems to mainly be a problem at slow exposures. For instnace, if I set the min speed to 1/4 and shot a dark scene  ISO will never really go above 200, thus spoiling the picture. But if I set the min speed to 1/60, ISO will increase a lot more (but never above 1250, it seems), which is often enough to correctly expose the picture.

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Offline longtalker

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Re: Reducing the minimum exposure speed in High-speed Burst HQ mode
« Reply #57 on: 12 / March / 2014, 19:55:09 »
Any idea at all when/if the remaining problem that I mentioned will be fixed?


Re: Reducing the minimum exposure speed in High-speed Burst HQ mode
« Reply #58 on: 12 / March / 2014, 20:07:51 »
Any idea at all when/if the remaining problem that I mentioned will be fixed?
Possibly never.   If I can reproduce on my SX50 I'll take a look when I have some time.  But that might be several weeks from now and there is no guarantee that I can fix it.
Ported :   A1200    SD940   G10    Powershot N    G16

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Re: Reducing the minimum exposure speed in High-speed Burst HQ mode
« Reply #59 on: 13 / March / 2014, 06:20:31 »
Alright no worries, thanks again

 

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