Real vs market ISO - page 2 - General Discussion and Assistance - CHDK Forum

Real vs market ISO

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Re: Real vs market ISO
« Reply #10 on: 06 / July / 2013, 23:07:44 »
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Oh, I misunderstood. Not sure about that, but at least it would be consistent.
I'm reaching for the minimal solution that lets me enter things in market values - never cared much about ISO override or brackeing but Custom Auto ISO is starting to look like it shoots the way I shoot.  And I just submitted a patch that (amongst other things) removes the ability to enter market ISO values.

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What I was thinking of was just to have a fixed default real/market conversion in the code and allowing overriding it on a per platform basis. I would want to have the real/market values for a decent sample of cameras before doing this, but assuming they were all fairly similar, I think it would be ok.
Okay - I'll do the script thing to collect "figures of merit" unless someone else volunteers.    This ends up like the voltage values for the battery OSD percentage display I guess.
Ported :   A1200    SD940   G10    Powershot N    G16

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Offline reyalp

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Re: Real vs market ISO
« Reply #11 on: 06 / July / 2013, 23:51:11 »
I used the following chdkptp command on my cameras, replacing 80 with each of the ISO values available in the menu
Code: [Select]
=p=require'propcase' set_prop(p.ISO_MODE,80) press('shoot_half') repeat sleep(10) until get_shooting() return get_prop(p.ISO_MODE),get_prop(p.SV),get_prop(p.SV_MARKET),get_prop(p.DELTA_SV)
This has to be done in a mode that supports manual ISO.

DELTA_SV is only non-zero in Canon auto ISO mode, so could be left off. Auto-ISO can be set by setting ISO_MODE to 0.

The result is that both a540 and d10 give essentially identical values to what I posted in http://chdk.setepontos.com/index.php?topic=8613.msg90280#msg90280
except that the a540 only goes to 800, and the D10 ISO3200 scene mode gives the expected values for ISO 3200

In modes support manual, you can just override ISO_MODE before half-shoot. I wasn't really clear about this before.

Attached ODS spreadsheet includes my tested values and formulas to convert the values. The UI, sv96 and sv96_m should be entered.

I'm not sure if the sd990 ISO 80 being 370 (vs 371 for other cameras) is real or a typo.

If a reasonable sample of other cameras follow the same pattern, I think a hard coded conversion is the way to go.

edit:
I'll turn this into a standalone script
« Last Edit: 07 / July / 2013, 00:02:17 by reyalp »
Don't forget what the H stands for.

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Offline reyalp

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Re: Real vs market ISO
« Reply #12 on: 07 / July / 2013, 00:40:39 »
Script is attached. The parameters are start and end ISO, which should be the min and max values that appear in the normal canon ISO menu. It assumes there is at most 1 step below ISO 100, and from 100 onward each step is 2x the previous value.

It will attempt to switch to record if needed, and then switch to P mode, which AFAIK should exist on all (?) cameras and have manual ISO.

The output is in isotest.csv in the root of the SD card.

Don't forget what the H stands for.

Re: Real vs market ISO
« Reply #13 on: 07 / July / 2013, 00:54:20 »
Script is attached.
Thanks for doing that.  Late here now - I'll run tomorrow and post results for my four cameras.
Ported :   A1200    SD940   G10    Powershot N    G16


Re: Real vs market ISO
« Reply #14 on: 07 / July / 2013, 00:59:55 »
Okay - couldn't resist doing at least one.  Here's the result from the G10 - I added a column for the "slope" value  (market/real) - should be possible to do that from the script I guess.

As expected,  ISO 80 is different than the rest, which are all pretty consistent.
« Last Edit: 07 / July / 2013, 01:02:10 by waterwingz »
Ported :   A1200    SD940   G10    Powershot N    G16

Re: Real vs market ISO
« Reply #15 on: 07 / July / 2013, 10:29:52 »
Another update - not good news.  Might be script problems? Or problems with setting ISO on my older ports?   Or the propcases don't work as expected for propset 2 &3 ?

The G10 values I posted above are essentially all the same (except for ISO 80).  It doesn't appear to be able to change the values.  Multiple runs show that the sv96 value is the normal value for the current brightness level, so its not being overwritten.

The ixus120_sd940 will not go into P mode - script aborts with error() statement.  Tried different Canon modes and settings - no joy.  If I print the capmode.get_name() result prior to try to set it to P it says "UNKNOWN" the first time after a powerup and then "AUTO" then next time - regardless of the position of the AUTO/P slide switch.  I converted the error() to a print() and let the script run.  Results attached - not looking good.

The sx50 and a1200 are identical - at least that seems like a good thing.

Before I attempt to "fix" this myself,  I'm open to suggestions.

« Last Edit: 07 / July / 2013, 11:10:45 by waterwingz »
Ported :   A1200    SD940   G10    Powershot N    G16

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Offline srsa_4c

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Re: Real vs market ISO
« Reply #16 on: 07 / July / 2013, 11:50:00 »
Looks like old cameras are unpredictable. Below table is market ISO (Canon UI) vs sv96.

Since get_shooting() appeared to have failed on ixus40, I used a script with fixed delay on some cameras to obtain the results, should not make a difference though.

@msl: agreed, hopefully a mod will split these posts into a new thread
« Last Edit: 07 / July / 2013, 11:54:50 by srsa_4c »

Re: Real vs market ISO
« Reply #17 on: 07 / July / 2013, 11:50:13 »
Perhaps it is better we start a new topic about ISO issues. This thread should be more a overview for 1.2 release.
A new thread might be a good idea at this point but these posts are here primarily because we are discussing a wholesale switch to using market ISO everywhere in the UI prior to 1.2.0 being declared the stable branch.
Ported :   A1200    SD940   G10    Powershot N    G16


Re: Real vs market ISO
« Reply #18 on: 07 / July / 2013, 11:53:23 »
Looks like old cameras are unpredictable.
Are those real or market sv96 values?   They appear to shift up & down together so the multiplier will be different - that's okay.  We need to understand if they are linear - can you fill out reyalp's spread sheet for some of them?
Ported :   A1200    SD940   G10    Powershot N    G16

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Offline srsa_4c

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Re: Real vs market ISO
« Reply #19 on: 07 / July / 2013, 12:01:13 »
Are those real or market sv96 values?
Real (I've updated that post).
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can you fill out reyalp's spread sheet for some of them?
Details in the attached spreadsheet.

 

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