Author Topic: Dual ISO: Why not Tri?  (Read 740 times)

davidevans

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Dual ISO: Why not Tri?
« on: October 29, 2018, 05:02:51 AM »
If magic lantern can control the ISO that is pulled down on a line by line basis, why use just 2 ISOs?  Why not 3 to get some midrange back when the spread is large? 

I understand that more processing is required to stitch the images back together and that there is an effective loss of detail in blown out areas, etc.  I am asking whether it is theoretically possible. 

R

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Re: Dual ISO: Why not Tri?
« Reply #1 on: October 29, 2018, 12:11:51 PM »
As far as I know, I don't think it's possible, and if it were I suppose aliasing and moiré would increase.

Levas

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Re: Dual ISO: Why not Tri?
« Reply #2 on: October 29, 2018, 06:11:16 PM »
Dual-iso, using 2 iso settings in one shot, is possible because Canon CMOS have a hardware setting that allows the use of 2 different iso’s.
More then 2 different iso’s in one shot is not possible, hardware limitation.
But nothing stops you from using multiple dual iso settings in multiple shots.
Exposure bracketing with dual iso.
Not sure if anyone has automated this with a Lua script  ???
If anyone, user Garry23 has some lua scripts for exposure bracketing and such, search for his posts on this forum.

garry23

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Re: Dual ISO: Why not Tri?
« Reply #3 on: October 29, 2018, 11:38:23 PM »
@R and @Levas

I do exposure bracket with ISO and wrote a script to do this when handholding (sic). For example https://www.magiclantern.fm/forum/index.php?topic=21602.0


davidevans

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Re: Dual ISO: Why not Tri?
« Reply #4 on: October 30, 2018, 01:59:39 AM »
Thank you