CHDK Spotmeter - page 2 - General Discussion and Assistance - CHDK Forum

CHDK Spotmeter

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Re: CHDK Spotmeter
« Reply #10 on: 23 / July / 2010, 10:14:33 »
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ok is that something that someone like me (not a coder) could reasonably do?

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Offline hwntw

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Re: CHDK Spotmeter
« Reply #11 on: 23 / July / 2010, 10:29:37 »
I tried the diff and compiling using CHDK-Shell, this is the error msg:
<
gui.c:532: error: 'LANG_MENU_METER_SHOW' undeclared here (not in a function)
gui.c:533: error: 'LANG_MENU_METER_ISO' undeclared here (not in a function)
gui.c:534: error: 'LANG_MENU_METER_SHUTTER' undeclared here (not in a function)
gui.c:537: error: 'LANG_MENU_METER_PARAMS' undeclared here (not in a function)
gui.c:537: error: initializer element is not constant
gui.c:537: error: (near initialization for 'meter_submenu.title')
gui.c:763: error: initializer element is not constant
gui.c:763: error: (near initialization for 'osd_submenu_items[19].text')
D:\COLHDK2\gcc4\bin\gmake.exe[1]: *** [gui.o] Error 1
gmake: *** [all-recursive] Error 1>
How to fix these errors, anyone?
Ixus 95 IS Ixus 30 izoom Powershot S80 S100 S200


Windows 10

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Offline fudgey

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Re: CHDK Spotmeter
« Reply #12 on: 23 / July / 2010, 15:25:01 »
I tried the diff and compiling using CHDK-Shell, this is the error msg:
...
How to fix these errors, anyone?

This patch is a bit old old, meaning it is likely that it can't be applied to current CHDK source tree without modification. If you tried to build a recent trunk revision, this is probably the reason it fails.

Looks the patch was made for rev 800, you can pull that one out of the svn and try it instead. If CHDK didn't support your camera back then (September 2009) or if you want the new features/fixes developed since, you need to port the patch.

Re: CHDK Spotmeter
« Reply #13 on: 24 / July / 2010, 02:33:46 »
Ok not sure who to tell here, but a spotmeter to use with these cameras would be extremely useful to a lot of different photographers who still use film (that's a lot of people).  Not sure if this script would be any good in the long run but a spot meter (or better yet a full functioning zone system meter) would be great.

The point would be to use the camera as a light meter and film exposure tool to carry around with a large format camera.


Re: CHDK Spotmeter
« Reply #14 on: 27 / July / 2010, 07:22:55 »
Any hope for this?

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Offline kuku

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Re: CHDK Spotmeter
« Reply #15 on: 16 / May / 2011, 02:40:23 »
Hi - I know its an old thread but I found nothing about it on the forum,and I think someone can use this fork to get the lightmeter functionality to chdk: http://code.google.com/p/chdk-lm/

Re: CHDK Spotmeter
« Reply #16 on: 06 / January / 2012, 09:35:16 »
The patch that dean0 posted is lost and the link to chdk-lm on GoogleCode gives me permission denied error 403.

Wouldn’t it be possible to make a pure lua light meter script? I mean Lua can draw widgets too, no?

Re: CHDK Spotmeter
« Reply #17 on: 06 / January / 2012, 14:04:05 »
To reply to myself,

with pure Lua scripting you can only make a [admin: avoid swearing please] light meter. Lua doesn’t give you arithmetic functions like log2 since it’s all integer based. So either you display stuff in the awkward APEX96 values and require input parameters in those of you have to resort to crummy lookup tables.

I’ve compared the EV measured values with my analogue Gossen and my digital Sekonic and it matches pretty well. Hence I conclude that it could be done in C code where you can work with decimal numbers, which is necessary since I want to meter outside of the normal range as well.

My pinhole camera has an aperture of f/500 and I'd like to directly meter for this stop and get the proper exposure time, not the other way around. The aperture is fixed obviously. Giving me time in seconds would be sufficient.

Since my Gossen’s scale goes up to f/90 only this would make things easier. I could add a compensation for reciprocity failure as well, since that varies from film to film. But that is usually and exponent to e and hence again requires floating point math.

Here’s an example: http://pinhole.stanford.edu/phcalc3.htm . I would like to implement a subset of that in the camera.


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Offline fudgey

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Re: CHDK Spotmeter
« Reply #18 on: 08 / January / 2012, 05:00:58 »
Here's a copy of the attachment that must have gone missing in one of the forum changes..

Re: CHDK Spotmeter
« Reply #19 on: 08 / January / 2012, 06:27:24 »
It would not be too hard to implement a fixed-point library for Lua; it's certainly been done a few times before in other contexts.

 

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