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CHDK ISO override.

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Offline philmoz

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CHDK ISO override.
« on: 30 / July / 2011, 19:50:36 »
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Apologies if this has been covered before, didn't find anything by searching.

While testing the ISO override on the IXUS 310 HS I noticed that the camera would not accept an ISO value lower than the currently selected Canon ISO setting.

So if the camera is set to ISO 3200, CHDK ISO overrides don't work.
If I set the camera to ISO 400, I can override to any value higher than this; but not lower.

If the camera is set to 'Auto' then all CHDK ISO overrides work (auto seems to be considered the 'lowest' ISO value).

I also tested this on the G12 and SX30 and both of them behave the same way.

I'd be interested to know if any other cameras work like this - or is it specific to how I've done the ports for these cameras.

Phil.
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CHDK ports:
  sx30is (1.00c, 1.00h, 1.00l, 1.00n & 1.00p)
  g12 (1.00c, 1.00e, 1.00f & 1.00g)
  sx130is (1.01d & 1.01f)
  ixus310hs (1.00a & 1.01a)
  sx40hs (1.00d, 1.00g & 1.00i)
  g1x (1.00e, 1.00f & 1.00g)
  g5x (1.00c, 1.01a, 1.01b)
  g7x2 (1.01a, 1.01b, 1.10b)
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Offline reyalp

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Re: CHDK ISO override.
« Reply #1 on: 31 / July / 2011, 23:51:26 »
D10 seems to work correctly in both directions, but there is some weirdness.

If you shoot with override, and then turn the override off, the override actually remains set until you change the Canon ISO in the menu, or go to play mode and back. I have a vague memory of this being discussed before somewhere.
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Offline funnel

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Re: CHDK ISO override.
« Reply #2 on: 01 / August / 2011, 04:27:49 »
SX220 appears to behave the same. Interesting that using ISO bracketing(-400) from 3200 works without problems.
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Offline philmoz

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Re: CHDK ISO override.
« Reply #3 on: 01 / August / 2011, 05:32:18 »
Quote from: funnel on 01 / August / 2011, 04:27:49
SX220 appears to behave the same. Interesting that using ISO bracketing(-400) from 3200 works without problems.

Yes, you're right. Hadn't noticed that.
Might mean there's hope it can work in all cases - need to do more investigation.

Phil.
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CHDK ports:
  sx30is (1.00c, 1.00h, 1.00l, 1.00n & 1.00p)
  g12 (1.00c, 1.00e, 1.00f & 1.00g)
  sx130is (1.01d & 1.01f)
  ixus310hs (1.00a & 1.01a)
  sx40hs (1.00d, 1.00g & 1.00i)
  g1x (1.00e, 1.00f & 1.00g)
  g5x (1.00c, 1.01a, 1.01b)
  g7x2 (1.01a, 1.01b, 1.10b)
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Offline philmoz

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Re: CHDK ISO override.
« Reply #4 on: 01 / August / 2011, 07:46:18 »
Quote from: philmoz on 01 / August / 2011, 05:32:18
Quote from: funnel on 01 / August / 2011, 04:27:49
SX220 appears to behave the same. Interesting that using ISO bracketing(-400) from 3200 works without problems.

Yes, you're right. Hadn't noticed that.
Might mean there's hope it can work in all cases - need to do more investigation.

Phil.


It looks like the cameras don't re-evaluate exposure between shots in continuous mode (or timer multi shot mode). So the bracketing override on the second and subsequent shots works - the first bracketed shot is at the camera set ISO value so you don't notice the override doesn't work.

It works in continuous shooting mode as well using the normal ISO override; but only after the first shot.

I tried moving the call to shooting_expo_param_override around; but so far it hasn't helped.

Phil.
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CHDK ports:
  sx30is (1.00c, 1.00h, 1.00l, 1.00n & 1.00p)
  g12 (1.00c, 1.00e, 1.00f & 1.00g)
  sx130is (1.01d & 1.01f)
  ixus310hs (1.00a & 1.01a)
  sx40hs (1.00d, 1.00g & 1.00i)
  g1x (1.00e, 1.00f & 1.00g)
  g5x (1.00c, 1.01a, 1.01b)
  g7x2 (1.01a, 1.01b, 1.10b)
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Offline Bernd R

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Re: CHDK ISO override.
« Reply #5 on: 01 / August / 2011, 11:48:06 »
Quote from: philmoz on 30 / July / 2011, 19:50:36
Apologies if this has been covered before, didn't find anything by searching.

While testing the ISO override on the IXUS 310 HS I noticed that the camera would not accept an ISO value lower than the currently selected Canon ISO setting.

So if the camera is set to ISO 3200, CHDK ISO overrides don't work.
If I set the camera to ISO 400, I can override to any value higher than this; but not lower.

If the camera is set to 'Auto' then all CHDK ISO overrides work (auto seems to be considered the 'lowest' ISO value).

I also tested this on the G12 and SX30 and both of them behave the same way.

I'd be interested to know if any other cameras work like this - or is it specific to how I've done the ports for these cameras.

Phil.


I dont think chdk can work with existing code on new cameras with ISO overwrite.I have written how it can work in the ixus 300 porting thread.My ixus 1000 work ok this way

http://chdk.setepontos.com/index.php?topic=5574.msg61888#msg61888

Have you try this code and it do not work ?
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Ixus 1000 HS
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Offline philmoz

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Re: CHDK ISO override.
« Reply #6 on: 05 / August / 2011, 19:00:45 »
The following change fixes the ISO override on the G12, SX30 and IXUS310.
It now works regardless of which ISO is set in the camera settings.

Calling shooting_expo_param_override twice as shown below seems to have done the trick.

In capt_seq.c (note addresses will vary between cameras/firmware versions):
Code: [Select]
// jump table entry 0
"loc_FF882700:\n"

" BL shooting_expo_param_override\n"  // *** added additional call to fix overrides

" BL sub_FF882E00 \n"

" BL shooting_expo_param_override\n"  // original call for overrides

" BL sub_FF87FF5C \n"

Phil.
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CHDK ports:
  sx30is (1.00c, 1.00h, 1.00l, 1.00n & 1.00p)
  g12 (1.00c, 1.00e, 1.00f & 1.00g)
  sx130is (1.01d & 1.01f)
  ixus310hs (1.00a & 1.01a)
  sx40hs (1.00d, 1.00g & 1.00i)
  g1x (1.00e, 1.00f & 1.00g)
  g5x (1.00c, 1.01a, 1.01b)
  g7x2 (1.01a, 1.01b, 1.10b)
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Offline reyalp

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Re: CHDK ISO override.
« Reply #7 on: 05 / August / 2011, 22:35:28 »
in script, shooting_expo_param_override resets the override value, so calling it twice will probably not work there.

There is also a bug in shooting_expo_param_override, it uses 0 to indicate the value should not be set, even though 0 is a legal value for tv96  :(
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Offline philmoz

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Re: CHDK ISO override.
« Reply #8 on: 05 / August / 2011, 23:01:40 »
Quote from: reyalp on 05 / August / 2011, 22:35:28
in script, shooting_expo_param_override resets the override value, so calling it twice will probably not work there.

There is also a bug in shooting_expo_param_override, it uses 0 to indicate the value should not be set, even though 0 is a legal value for tv96  :(

Thanks reyalp, nothings ever easy is it.

Tried various locations in the function between these two calls; but can't find a location that works properly.

If I just do the ISO override in the first call (with a new function) and then do the full override in the second it seems to work. Can you see any problems with this?

Code: [Select]
// jump table entry 0
"loc_FF882700:\n"

" BL shooting_expo_iso_override\n"      // added

" BL sub_FF882E00 \n"

" BL shooting_expo_param_override\n"  // added

" BL sub_FF87FF5C \n"

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CHDK ports:
  sx30is (1.00c, 1.00h, 1.00l, 1.00n & 1.00p)
  g12 (1.00c, 1.00e, 1.00f & 1.00g)
  sx130is (1.01d & 1.01f)
  ixus310hs (1.00a & 1.01a)
  sx40hs (1.00d, 1.00g & 1.00i)
  g1x (1.00e, 1.00f & 1.00g)
  g5x (1.00c, 1.01a, 1.01b)
  g7x2 (1.01a, 1.01b, 1.10b)
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Offline reyalp

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Re: CHDK ISO override.
« Reply #9 on: 05 / August / 2011, 23:08:16 »
Seems like it should work to me.

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