Kap script (or any other script) for general camera settings?

shinnen

Kap script (or any other script) for general camera settings?

« on: 03 / November / 2017, 10:21:26 »

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Hi,
I imagine that this question has probably been asked before, but here goes.
Could the KAP script, or any other script for that matter, be used as the default script for general use on my a590?
Thanks,
..... john

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waterwingz

12032

Re: Kap script (or any other script) for general camera settings?

« Reply #1 on: 03 / November / 2017, 11:35:08 »

Quote from: shinnen on 03 / November / 2017, 10:21:26

Could the KAP script, or any other script for that matter, be used as the default script for general use on my a590?

The answer to your question is “Yes”.

But maybe I don’t really understand your question? Is there some reason that makes you suspect that it can’t be used?

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Ported : A1200 SD940 G10 Powershot N G16

shinnen

Re: Kap script (or any other script) for general camera settings?

« Reply #2 on: 03 / November / 2017, 12:33:14 »

Hi Waterwingz,
No, no reason at all. It certainly seems well qualified for the job. But is there any way of automatically controlling the exposure, without using bracketing, so that the camera's number one priority is to seeks a preset 'brightness', regardless of the brightness of the scene.
.... john

« Last Edit: 03 / November / 2017, 12:35:38 by shinnen »

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waterwingz

12032

Re: Kap script (or any other script) for general camera settings?

« Reply #3 on: 04 / November / 2017, 13:12:02 »

Quote from: shinnen on 03 / November / 2017, 12:33:14

But is there any way of automatically controlling the exposure, without using bracketing, so that the camera's number one priority is to seeks a preset 'brightness', regardless of the brightness of the scene.

I'm not sure I understand what you are looking for here. How would you define "preset brightness" level?

Normally, your camera tries for an average overall brightness in the "metering" area that centers between overexposed and underexposed (yes - I know it's more complicated than that but for today's purposes it's good enough). You can then use the Ev adjust function to move the exposure relative to that average.

In M mode, for any Tv, Sv, Av setting, you get a defined percentage of the incoming light through to the sensor. But the actual amount changes with the scene brightness of course.

I guess using apex96 math (see Doug Kerr's APEX Article) you could use the formula :

Code: [Select]

Bv=Av+Tv-Sv

in a script to pick Tv, Av, Sv values that will give you a fixed Bv. But is that really what you want to do?

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Ported : A1200 SD940 G10 Powershot N G16

shinnen

Re: Kap script (or any other script) for general camera settings?

« Reply #4 on: 06 / November / 2017, 09:41:46 »

Hi,
I guess what I'm really getting at is that, when I set my iso very low, the actual setting is 30, my LCD does not give me an accurate reading of what the picture will look like, brightness wise. The actual picture is usually much darker. Is there any way of fixing that, so that what I see on my LCD is close, in brightness, to what the shot will look like?
.... john

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waterwingz

12032

Kap script (or any other script) for general camera settings?

« Reply #5 on: 06 / November / 2017, 09:57:56 »

Quote from: shinnen on 06 / November / 2017, 09:41:46

when I set my iso very low, the actual setting is 30,

FWIW, while you can set ISO values as low as you'd like, in reality the camera won't go much below 80 when you actually shoot.

Quote

my LCD does not give me an accurate reading of what the picture will look like, brightness wise. The actual picture is usually much darker. Is there any way of fixing that, so that what I see on my LCD is close, in brightness, to what the shot will look like?

There are two issues here. The first is that the Canon firmware does not know that CHDK is about to change the ISO setting and so does not adjust your display. The second is that CHDK currently does not have the ability to change the brightness. So there is nothing we can do here.

« Last Edit: 06 / November / 2017, 10:08:10 by waterwingz »

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Ported : A1200 SD940 G10 Powershot N G16

shinnen

Re: Kap script (or any other script) for general camera settings?

« Reply #6 on: 06 / November / 2017, 12:21:14 »

Hi,
Yes, I'm aware that iso 30 in CHDK, is not really iso 30. I only chose that value because I suspect it will set the camera at it's lowest possible iso. I ran the isoinc.lua from 20 to 200, which produced an isoinc.csv file, but I can't make head nor tail of it. I assume it will answer the question re the lowest iso the camera will actually achieve. I am including a copy of the file. Perhaps you know how to read it.
Thanks for explaining the disparity between the LCD and image brightness.
....... john