Inconsistent ISO and Shutter Speed

ThatGuyOverThere

4

« on: 05 / August / 2015, 18:54:43 »

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Hello,

I have been using a USB triggered CHDK script in my Canon PowerShot SX260. It has been working well, but I have recently run into some issues.

For some reason, the pictures that the camera takes will have two different ISO values even though I'll have it set at a consistent value in both the camera and script settings. For example, I will run the script and it will take 400 pictures while being triggered and every ISO value is set to 200. For some reason, the pictures it produces will almost all be 100 ISO and a handful will be 200 ISO... Is there a reason this is happening? I'm completely out of theories especially since every ISO value is set to be the same.

Additionally (this could go hand-in-hand with the issue mentioned above), when setting the shutter speed of the camera, while in manual mode, something similar happens where the script seems to overwrite the values I put in. It was confirmed afterward that the shutter speed did not change to the value I thought I had placed it at. Once again, is there a reason this is occurring?

Any insight/help is welcome!!

Thanks.

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waterwingz

12138

Re: Inconsistent ISO and Shutter Speed

« Reply #1 on: 05 / August / 2015, 19:29:05 »

Please post a copy of the script you are using.

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Ported : A1200 SD940 G10 Powershot N G16

ThatGuyOverThere

4

Re: Inconsistent ISO and Shutter Speed

« Reply #2 on: 07 / August / 2015, 13:00:35 »

I have included the link for the script we are using -- KAP UAV Exposure Control Script

http://chdk.wikia.com/wiki/KAP_UAV_Exposure_Control_Script

Thanks!

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waterwingz

12138

Re: Inconsistent ISO and Shutter Speed

« Reply #3 on: 07 / August / 2015, 14:29:08 »

Quote from: ThatGuyOverThere on 07 / August / 2015, 13:00:35

I have included the link for the script we are using -- KAP UAV Exposure Control Script http://chdk.wikia.com/wiki/KAP_UAV_Exposure_Control_Script

Well that's a good start - I'm "somewhat" familiar with that script. It produces a log file by default and saves it on your SD card. It's called kap.log and should be in the root folder of the card. Would you please find and post that file here as an attachment?

Quote from: ThatGuyOverThere on 05 / August / 2015, 18:54:43

For some reason, the pictures it produces will almost all be 100 ISO and a handful will be 200 ISO

Are the resulting images correctly exposed? For example, when the ISO changes from 200 to 100 is the shutter speed doubled to compensate?

Quote

Additionally (this could go hand-in-hand with the issue mentioned above), when setting the shutter speed of the camera, while in manual mode, something similar happens where the script seems to overwrite the values I put in. It was confirmed afterward that the shutter speed did not change to the value I thought I had placed it at.

If you set an exposure value (Tv, Sv, Av) manually using the CHDK menus and then let the script run, CHDK will override those values with the ones requested by the script.

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Ported : A1200 SD940 G10 Powershot N G16