Will Override Shutter/ISO or Aperture ever be enabled in Movie Mode? - Feature Requests - CHDK Forum supplierdeeply

Will Override Shutter/ISO or Aperture ever be enabled in Movie Mode?

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Is there some technical reason why these variables cannot be controlled when in movie mode?
I noticed that even when enabling the AE lock on the Powershot S5, the shutter can be 1/100th sec. (should be 1/60th).
Also seem to recall that the ISO is all over the place when in Movie mode. Would be great to lock down the gain to ISO 50.

It's really cool that optical zoom has now been ported to non S-series cameras, thanks EWAVR!



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Offline PhyrePhoX

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Re: Will Override Shutter/ISO or Aperture ever be enabled in Movie Mode?
« Reply #1 on: 15 / April / 2008, 05:37:59 »
shutter override works fine during video on s3is - but only when not in movie mode, meaning that when i am in m mode or even automatic, enable the overrides and then start video (with dedicated video rec button) the overrides are used in the resulting shots.
so, i guess this is just a simple fix.
edit: it even works when mode dial is set to movie. it just isnt shown on screen. as soon as you start recording it should be shown again. so, overrides do work in all modes, at least on s3is. on s5is this also should work.?!?
« Last Edit: 15 / April / 2008, 05:56:46 by PhyrePhoX »

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Offline vit40

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Re: Will Override Shutter/ISO or Aperture ever be enabled in Movie Mode?
« Reply #2 on: 15 / April / 2008, 07:57:58 »
I think  Stimpy  is asking about shutter/ISO/aperture override/control during video clip recording, like on camcorders

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Offline ewavr

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Re: Will Override Shutter/ISO or Aperture ever be enabled in Movie Mode?
« Reply #3 on: 15 / April / 2008, 21:22:18 »
So, manual exposure during video recording is possible (at least, on A710):

DoAELock() (and/or some similar functions) other locks current exposure (exposure is fixed),
UnlockAE() (and/or some similar functions) unlocks current exposure (i.e. exposure adjusted automatically),
ExpCtrlTool.OneShotAE() adjusts current exposure according to light condition and locks exposure,
RectifyExposureWithMeasure()  (and/or some similar functions) adjust current (locked) exposure according to propcase #26
Warning: call this function once before first video recording, otherwise camera may shut down.

But EV correction to auto exposure still not found  :(



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Offline vit40

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Re: Will Override Shutter/ISO or Aperture ever be enabled in Movie Mode?
« Reply #4 on: 16 / April / 2008, 02:52:25 »
Well, S and G series already have possibility to lock exposure and correct it up or down in video mode.
For movie shooters, it would be usefull to:

- enable this on other cameras
- enable ISO override/control
- enable shutter override/control

Anyway, I don't miss these features very much, because automatic exposure/shutter/ISO control is quite good

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Offline PhyrePhoX

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Re: Will Override Shutter/ISO or Aperture ever be enabled in Movie Mode?
« Reply #5 on: 16 / April / 2008, 02:57:44 »
i dont get it, shutter override during video recording? call me stupid, but during video recording the shutter should stay open at all times, am i right?

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Offline vit40

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Re: Will Override Shutter/ISO or Aperture ever be enabled in Movie Mode?
« Reply #6 on: 16 / April / 2008, 04:34:50 »
Electronic CCD shutter is obviously used here. You can see shutter speed of the first frame in EXIF of thumbnail file (which is a jpg with .thm extension). On low light it's 1/30, otherwise shorter (1/40, 1/50 ...)

In film world, preferred shutter speed is, as I was told, 1/2 of frame duration (1/48)

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Offline a710is

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Re: Will Override Shutter/ISO or Aperture ever be enabled in Movie Mode?
« Reply #7 on: 16 / April / 2008, 05:49:54 »
yea having just the right electronic shutter time Tv-style would create smoother video in well lit environments.
« Last Edit: 16 / April / 2008, 05:51:39 by a710is »


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Offline vit40

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Re: Will Override Shutter/ISO or Aperture ever be enabled in Movie Mode?
« Reply #8 on: 16 / April / 2008, 06:01:37 »
Unfortunately not - camera can lower ISO to minimum, close aperture to about F/13, but must also shorten exposure to prevent blowing, so you have strange looking "stroboscopic" video, and in case of my A620, some dust on the sensor is slightly visible because of so small aperture on strong daylight

Some external ND filter would be of help (in case you don't have G series that comes with built in ND filter)

Re: Will Override Shutter/ISO or Aperture ever be enabled in Movie Mode?
« Reply #9 on: 16 / April / 2008, 06:14:35 »
Vit40 - you'd be right in saying shutter rate is normally 1/2 frame rate - I think they call it a 180 degree shutter.

 Also, PAL video would use 1/50th, NTSC 1/60th for standard TV frame rates.

In most situations you would want to lock the shutter speed down to 1/60th when shooting 30 fps, (as the Canons basically shoot at NTSC rates).
If you get into low light situations you'd want to first open up the aperture, then when that reached wide open, gain up a few DB before you finally had to resort to lowering the shutter speed down.  It's in that order that would give the best image quality and asthetics.

As in still photography, the best image quality is when you have smaller apertures and zero gain, (especially on small CCD cameras).

An option in the menu to lock the shutter speed to 1/60th and gain locked to zero would be a huge improvement.
Even with lots of available light, the shutter sometimes cranks up to 1/100th which gives an odd stuttery appearance.









« Last Edit: 16 / April / 2008, 08:24:47 by Stimpy »

 

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