@srsa_4c, thank you *very much* for the detailed explanation. It makes more sense now, why the exp_drv_task hook was where it was, in with capt_seq.
Can you please test extra long (and extra short) exposures, using vanilla, unaltered svn? I had the impression that at least extra long ones are already working.
I build with vanilla src sx530hs, trunk revision_4826.
tl;dr: Yes, vanilla src can exceed Canon firmware values on both sides of the range. Tested Short=.00039, Long=2:00.
So, either way, I can do this; I made what I had posted previously work with exp_drv_task present, and now I've tested vanilla src with exp_drv_task absent. Works either way. Let me know which approach is preferred, I'll work through code_gen.txt, and submit.
Thanks again for the extra words.
test details long/short exposure sx530hs
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Short exposure test; 3 shots, same indoor target & lighting
1st = .001 sec
2nd = .00049 sec
3rd = .00039 sec
All tests took pictures, no errors, no CHDK complaints. Exifprobe data 'ShutterSpeedValue' for the images reports the first and second exposures correctly.
At .00039, the exifprobe data still says = 10.9688 APEX = '0.000498973 sec', even though CHDK-MainMenu -> EnhancedPhotoOps -> Override Tv ->
ShortExposureValue is set at 0.00039
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Long exposure test; 2 shots, outdoors on clear night
1st = 1:30
2nd = 2:00
No errors, no CHDK complaints. exifprobe says
ShutterSpeedValue = 1.34218e+08 APEX = '0 sec'
Wow, images are striking; it looks like funny daylight, except you can see stars and a good sized planet, even with no real zoom in effect. Noise is visible in the "darker" areas of images. The 2min image is "brighter", and has more noise..
Test images and exifprobe data from above are available if useful.