Improving CHDK ND filter support

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Re: Improving CHDK ND filter support
« Reply #20 on: 02 / September / 2017, 16:15:32 »
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If it works this way, you should be able to find this point just by adjusting the Tv value, starting with one that gives you Av < 8.
 
And probably with a hysteresis for in and out…

I want to understand some basics about ND…
How does the cam made exposure measure in AV mode when I set AV=8.0?
My understanding was, the cam opens aperture, do the exposure measure and closes only aperture while shooting.

What happen on S110 if I switch the ND in canon UI on? I see that the screen just goes a little bit dark. So the ND is really in? What happens if I do half press? Does the cam measure exposure (and focus) with ND in? Why the cam should do this? It made measure and focus much harder….

What happens on SX50 after half press? Does ND really goes in or only at full shoot?


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Offline reyalp

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Re: Improving CHDK ND filter support
« Reply #21 on: 02 / September / 2017, 16:54:15 »
I want to understand some basics about ND…
How does the cam made exposure measure in AV mode when I set AV=8.0?
My understanding was, the cam opens aperture, do the exposure measure and closes only aperture while shooting
On g7x, I can see the aperture opens and then goes to the set value on half press. How far it's open in normal live view depends on lighting. The ND on elph130 behaves similarly: If you point it at a very bright scene, the ND goes in just in live view, without half pressing. In darker conditions it might still go in on half press.

On g7x, the ND state changes when it's set in the UI, and from sound I don't think it goes out for auto exposure in half press. Canon manual ND has been quite primitive, IIRC only in g7x mk2 they added the option for auto modes to control it.
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Offline reyalp

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Re: Improving CHDK ND filter support
« Reply #22 on: 02 / September / 2017, 22:51:07 »
ND related eventprocs etc (from elph130, but similar exist on many cameras)

PutInNdFilter
PutOutNdFilter
What we use for ND control

ReloadNdFilterAdjustment
implies there is some kind of camera specific ND calibration, though it could be actuator rather than value related.

TurnOffNdFilter
TurnOffNdFilterWithTiming
TurnOnNdFilter
TurnOnNdFilterWithTiming
Appear to be lower level functions than PutIn / PutOut

SetNdDriveVoltageSetting
GetNdMoveTime
SetNdMoveTime

task_Nd
Reverse engineering and hooking this might provide insight (and possible control, though it appears to be lower level than the event procs)

Possibly ND related LogCameraEvent strings
M:ND_OFF_E
M:ND_OFF_S
I don't see these in c_joerg's logs, or in logs from elph130 when ND is triggered.
Don't forget what the H stands for.

Re: Improving CHDK ND filter support
« Reply #23 on: 03 / September / 2017, 06:44:59 »
If it's using ND, it seems like there should be a light level (or Tv value) where the ND goes in and the Av drops below 8, like
Av = 8, no ND
move to 1 stop brighter light
Av = 4 (- 2 stops), ND in (+3-ish stops)
 
This confuses me more and more…
I looks like that the sound which I here could be also the aperture….

Make a test video. Had to do amplifier Audio to +20dB
All done in MF Mode
First Part: AV mode f5.6. If I do a half press. The sound which I here must come from aperture or?
Second part: TV Mode 1/10s. If I put my hands in front of the cam, I here same noise as from the first part. Not sure if this is aperture or ND….




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Offline reyalp

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Re: Improving CHDK ND filter support
« Reply #24 on: 03 / September / 2017, 15:03:54 »
Hard to know much based on sound unless you have a way to verify that you can distinguish between the aperture and the ND. On the G7X, I can tell they are different because putting in the ND manually in the UI makes a distinct sound.

You could try to do this on one of your cams by triggering the ND with CHDK. One way to do this in chdkptp would be something like

Code: [Select]
=press'shoot_half' repeat sleep(10) until get_shooting() sleep(1000) set_nd_filter(1) sleep(1000) set_nd_filter(2) sleep(1000)Normally, when you call set_nd_filter, it just sets a flag to tell the camera to put in the ND in the next half press. If you call it inside half press, it takes effect immediately. The above code waits 1 second and then puts in the ND, which should allow you to distinguish the sound. You should also see the live view get darker.

edit:
Oops, had the ND control values reversed. Fixed.
« Last Edit: 03 / September / 2017, 18:37:28 by reyalp »
Don't forget what the H stands for.

Re: Improving CHDK ND filter support
« Reply #25 on: 04 / September / 2017, 15:05:29 »
Hard to know much based on sound unless you have a way to verify that you can distinguish between the aperture and the ND. On the G7X, I can tell they are different because putting in the ND manually in the UI makes a distinct sound.
Same on S110 or G1x. Sound between aperture and the ND is different.
Hard to say on SX50 which noise is aperture or ND.

The first part of the video shows you this execution in chdkptp
Code: [Select]
=press'shoot_half' repeat sleep(10) until get_shooting() sleep(3000) set_nd_filter(1) sleep(3000) set_nd_filter(2) sleep(3000)
I changed only sleep to 3s from your code. You can see that ND goes in and out. But you see here also three different brightness steps (off,in,out).

In the second part I tried to change the brightness slowly until I hear a sound. But at this time the brightness did not changed on live view. So not sure what that means.  May be the cam compensates the ND step immediately when ND goes on and off?
 

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Offline reyalp

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Re: Improving CHDK ND filter support
« Reply #26 on: 04 / September / 2017, 15:54:57 »
I changed only sleep to 3s from your code. You can see that ND goes in and out. But you see here also three different brightness steps (off,in,out).
This is weird. In half press, I'd expect other exposure params to stay fixed, but it seems like the camera must be changing something else on in or out.
Quote
In the second part I tried to change the brightness slowly until I hear a sound. But at this time the brightness did not changed on live view. So not sure what that means.  May be the cam compensates the ND step immediately when ND goes on and off?
I think this is normal when the camera puts ND on in live view. It's the same on my ND only cameras like elph130, firmware knows the ND value and adjusts the live view exposure at the same time. I can hear the click just aiming from indoors to a sunny window and back, and there's no iris to confuse things.
Don't forget what the H stands for.

Re: Improving CHDK ND filter support
« Reply #27 on: 05 / September / 2017, 01:49:34 »
I think this is normal when the camera puts ND on in live view. It's the same on my ND only cameras like elph130, firmware knows the ND value and adjusts the live view exposure at the same time.

But that is different on S110 and G1x . If I switch ND on, the live view goes just dark and got normalized after 1s.


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Offline reyalp

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Re: Improving CHDK ND filter support
« Reply #28 on: 05 / September / 2017, 15:50:42 »
But that is different on S110 and G1x . If I switch ND on, the live view goes just dark and got normalized after 1s.
Right, what I'm saying is that automatic ND behaves the same on ND-only ixus/elph style cameras and "hidden" ND cameras like sx50.

I suspect manual ND is done the way it is to give users a visual cue, but it could just be simpler implementation.
Don't forget what the H stands for.

Re: Improving CHDK ND filter support
« Reply #29 on: 16 / September / 2017, 12:41:41 »
On both elph130 and d10, I noticed that the zoom level seems to change very slightly with/without ND.
Same on G1x….
The Video shows ND switch in the middle of the video. The video has only 40 pictures with 10fps. The video is also a 1920*1080 crop from full picture.

Another interesting think is changing of noise in the video when the cam goes from ISO1000 to ISO130. I don’t use any noise reduction

I tried to correct this Video
With
Code: [Select]
align_image_stack -c 24 -i -x -y -a aligned_ *.jpg
But result looks worth…

The log file includes the full run. ND switch is close to the end.


 

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