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expanding exposure times on a590

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expanding exposure times on a590
« on: 13 / January / 2017, 14:34:28 »
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Hi,
     I've been trying to expand the exposure range of my a590 from the camera default of 15 seconds to 1/2000 seconds. Unfortunately the build that I'm using (1.5.0 revision 4747) does not seem to allow me to do this. Can someone suggest a version that will allow this, or a 'simple' script.
Thanks,
..... john

expanding exposure times on a590
« Reply #1 on: 13 / January / 2017, 15:56:27 »
Why do you say it does not allow you to do so? Are you unable to enter those extended values via the CHDK menu?  Or can you enter them but they don't seem to affect the resulting image? If so, did you check the actual appearance of the image or just the EXIF information?

This is most likely not version related.
Ported : A1200  SD940  G10  Powershot N  G16*

Re: expanding exposure times on a590
« Reply #2 on: 13 / January / 2017, 22:53:09 »
Hi,
       This version of CHDK doesn't have the entries under "Enhanced Photo Operations" for extending the range of exposure times. It will allow me to choose an exposure time and apply it, but not set a range. There is a version that allows this, I've seen it referred to on at least one site. I will try to find it and see if it works.
Thanks,
..... john

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Online reyalp

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Re: expanding exposure times on a590
« Reply #3 on: 13 / January / 2017, 23:17:32 »
Hi,
       This version of CHDK doesn't have the entries under "Enhanced Photo Operations" for extending the range of exposure times. It will allow me to choose an exposure time and apply it, but not set a range.
I'm not sure what you mean by set range, CHDK exposures overrides only ever let you set a specific exposure. Do the options you see look like this:
http://chdk.wikia.com/wiki/CHDK_User_Manual?file=Enhanced_menu_v2.png#Enhanced_Photo_Operations ?

The "override type" changes the entry format to allow longer and short values.
Don't forget what the H stands for.


Re: expanding exposure times on a590
« Reply #4 on: 13 / January / 2017, 23:59:35 »
HThis version of CHDK doesn't have the entries under "Enhanced Photo Operations" for extending the range of exposure times. It will allow me to choose an exposure time and apply it, but not set a range.
I'm not sure what you mean by set range, CHDK exposures overrides only ever let you set a specific exposure. Do the options you see look like this:
http://chdk.wikia.com/wiki/CHDK_User_Manual?file=Enhanced_menu_v2.png#Enhanced_Photo_Operations ?

The "override type" changes the entry format to allow longer and short values.
Further to what reyalp points out here,  the exposure time entry method changed  several years ago (2013) with the release of CHDK 1.2.0.  That might be what you are looking for.

If you really want to try out the old version, I can rebuilt a 1.1.0 release for you and post that here (the magic of source controlled in svn helps here).

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I've seen it referred to on at least one site. I will try to find it and see if it wor
If you find something that reyalp and I have never seen, we would be very interested to see it. Please post any links here?  Thanks!
Ported : A1200  SD940  G10  Powershot N  G16*

Re: expanding exposure times on a590
« Reply #5 on: 14 / January / 2017, 10:34:44 »
Hi Waterwingz,
   Thanks for your help. Yes, this is exactly the menu I have for Extra Photo Operations. But it only allows me to change the shutter speed to an exact value, not to expand the range.
Here's the menu I saw, that I 'think' would allow me the shutter speed flexibility I want .... perhaps not, I don't really know.
http://www.andrewhazelden.com/blog/2010/06/chdk-shutter-speed-overrides-explained/
   Perhaps I should explain what I'm trying to do. I have set my a590 (using CHDK) to an aperture value of 4.0 and and iso value of 64 (set number of 60). Then I start the camera in Tv, and vary the shutter speed to get the exposure I want. This gives me good control and sharp (low noise) stills. By fiddling around with CHDKplus I found that the shutter speed range can be expanded significantly, allowing me to shoot from 64 to 1/10,000 seconds, and photographing everything from very dark scenes to extremely bright ones (i.e. light bulbs, the sun), with fairly good results. I can, and have been using CHDKplus; but it has a glitch that messes up the review function, so that I have to go in and out of it to get the extended shutter speed range. Frankly, CHDKplus is a gross overkill for what I want, and I would just as soon not start it, if I don't have to.
 ... john   

Re: expanding exposure times on a590
« Reply #6 on: 14 / January / 2017, 12:05:16 »
Hi Waterwingz,
Here's the menu I saw, that I 'think' would allow me the shutter speed flexibility I want .... perhaps not, I don't really know.
That web page shows the CHDK "Extra Photo Operations" menu that was used prior to the release of CHDK 1.2.0.   That menu is called "Enhanced Photo Operations"  now and the way your enter override values has been made much simpler and more intuitive.

FWIW, CHDK has never allowed you to change the shutter speed range that the Canon firmware uses when it is setting the exposure.  You can "override" the value that the Canon firmware wants to use such that the actual exposure uses your setting rather than the Canon setting.  But you can't change the Canon setting or extend the range of values it choosed.  I don't think the web page you linked says otherwise.

Which brings up an interesting point that most people miss at first.  If you use CHDK to override just one of the three exposure values ( Tv, Av, or Sv ) and then take a picture, the Canon selected values for the other two will be used and the exposure will be incorrect unless your override value was the same as what Canon would have used.  Perhaps an example will help?

Lets say that you are photographing a normal daylight scene. The camera might set the exposure to 1/50 sec,  f8, and ISO 100. If you want a faster shutter speed then you can use CHDK to override the Tv value to 1/250.  But if you then take a picture, the exposure will be  1/250 sec, f8, and ISO 100 - very underexposed. To fix this you would need to manually set all three exposure values - say to 1/250, f2.8, ISO400.

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Perhaps I should explain what I'm trying to do. I have set my a590 (using CHDK) to an aperture value of 4.0 and and iso value of 64 (set number of 60).
fyi .. it's unlikely you are actually getting ISO64.  On pretty much every camera, the lower limit is about 80.  Attempting to set it lower with CHDK still gives you ISO80.  You can test for yourself - shoot at ISO 64, 80, and 100 with the Tv & Av values locked and observe the resulting images.

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I can, and have been using CHDKplus; but it has a glitch that messes up the review function, so that I have to go in and out of it to get the extended shutter speed range.
Tell me more about the "glitch".  Perhaps that can be fixed.

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Frankly, CHDKplus is a gross overkill for what I want, and I would just as soon not start it, if I don't have to.
I'm working on something that might address your concern but it's nothing I can share just yet.   

Meanwhile, would a simpler script that just lets you quickly change the shutter speed override value with the Up/Down buttons (or zoom lever) get you by?  You could set it up to run immediately when you press the <ALT> button, giving you a very quick adjustment option - perhaps even easier that the funky Canon interface.
« Last Edit: 14 / January / 2017, 12:09:36 by waterwingz »
Ported : A1200  SD940  G10  Powershot N  G16*

Re: expanding exposure times on a590
« Reply #7 on: 14 / January / 2017, 20:05:09 »
Hi,
     By shutter time range, I mean the shutter speeds, currently from 15 to 1/2,000 seconds. These are what I would like see expanded to 64 to 1/10,000 seconds, as CHDKplus allows. (When the mode selector wheel is set to Tv I can scan through the range of shutter speeds by using the left and right rockers on either side of the function button.)  When I do this using CHDKplus I see values from 64 to 1/10,000 seconds (not 15 to 1/2,000 seconds as the unscripted camera allows) . Using CHDKplus, the camera's exif info registers everything slower than 15 seconds as 15 seconds, and everything faster than 1/2,000 seconds as 1/2,000 seconds; but the reality is quite different. CHDK plus clearly increases the cameras fastest shutter speed to considerably greater than 1/2,000 (on the fast end), and to much much longer than 15 seconds (on the slow end). The 64 seconds is probably 64 seconds. I have no way of measure if CHDKplus' entry of 1/10,000 seconds is accurate, or not.
Thanks for the explanation of how the camera chooses settings.
I find that when I set the CHDK Av to 4.0, and iso to 60, the camera's exif says 4.0 and 64. I'm pretty sure that the camera will accept iso values below 80. I have tried every Av entry from 10 to 80; and the ones 60 and below are darker than the camera's own setting of 80. what the lowest iso is, I really don't know; but I suspect 64 may be it. 
The 'glitch', as I call it, happens when I want to view previous shots, while in CHDKplus. With the a590, viewing previous shots requires throwing a switch on the camera, which is there just for that purpose. That works fine, but I can only view the last image. When I try to view ones further back (which requires using the rocker to the left of the function button) I get kicked out of the review mode, and back into  shooting mode. (If I want to take more picture, I can just continue with the switch in the review position.) Only when I'm out of CHDKplus and turn the camera of and on, does the review switch behave normally. Odd, but that's what it does. It's not a big deal though, because I can exit, and enter, CHDKplus by hitting the Alt button.  I'm sorry if this sounds confusing. I've learned to work around this 'glitch'. I don't know of a better way to explain it.
Yes, a script that would allow me to access shutter speeds, longer, and faster, than what I presently can, would be great. If it could be made to work using the left and right rockers on either side of the camera's function button, the way that CHDKplus currently works (and as the camera normally works), would be nice.
Thanks again for your help.
...... john


Re: expanding exposure times on a590
« Reply #8 on: 14 / January / 2017, 20:27:41 »
I've learned to work around this 'glitch'. I don't know of a better way to explain it
Makes sense - I'll take a look at it.  None of my 5 or 6 cameras have a review mode switch so I guess it's not surprising that I didn't include switch handling when I wrote the script.

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Yes, a script that would allow me to access shutter speeds, longer, and faster, than what I presently can, would be great. If it could be made to work using the left and right rockers on either side of the camera's function button, the way that CHDKplus currently works (and as the camera normally works), would be nice.
I've been playing with the attached this afternoon.  When it runs you can adjust the shutter override with either the zoom lever or the right/left buttons.  Pressing anything else dumps you out of the script and <ALT> mode, ready for shooting with the selected override value all configured and ready to go.

I think it's pretty functional but I've only played with it a bit.  If you configure the CHDK Script menu item called  Autostart to  [ Alt ] then it will run when you press the ALT key (rather than enter CHDK ALT mode).  Press the shutter key while the script is running if you want to return to the CHDK menu rather than shooting.

One possible mod would be allowing you to set the Av and Sv values via User Parameters in the Script menu (you'll have to do that manually for now).

Edit :  script updated
« Last Edit: 16 / January / 2017, 03:21:59 by waterwingz »
Ported : A1200  SD940  G10  Powershot N  G16*

Re: expanding exposure times on a590
« Reply #9 on: 14 / January / 2017, 23:04:51 »
Thanks. I'll be out tomorrow, but will give it a go in a day or two.
.... john

 

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