Need 3 states for shooting (S110)

mr.burns

223

« on: 15 / April / 2015, 15:38:48 »

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Hi,

finally I found some time again to play a littlebit with my stereo pair of two Canon S110.
I am thinking about a feature I would like to have, may this can be done using CHDK and some hacking.
To make clear what I want I first disuss this with only one camera without CHDK.
My S110 shows this small focus rectangle in the middle of the LCD. Now I don't want to focus the center of the image but something more to the right. What I do now is pan the cam to the right to get the object into the rectangle, half press the shutter button to focus, keep the shutter half pressed and left pan the camera back to it's original position. With this steps I have locked the focus to my object, but the rectangle is now on it's original position again. This is the quickest way if you don't want to focus the object which is in the center of the image.
So far no problem. Now we discuss this with my stereo pair of two S110.
To get synced stereo images I enabled 'Enable remote' and 'Enable sync' under the 'CHDK Settings'. 'Switch type' is set to 'One push'.
If I press the USB switch both cameras start focusing. If focusing is finished the LCDs turn to black (to enter sync mechanism). And exactly this is my problem. If I want to lock the focus like I did with the single cam, then I can't. After the cams have focused the LCD is black so I cannot pan back to the original position anymore because I cannot see anything on the LCDs. If I disable 'Enable sync' then the LCDs keep on after focusing but then the cameras are not in sync anymore when shooting.

What I need are 3 states for USB switch (something like Ricoh CA-1):

1st state: Half press
2nd state: Full press
3rd state: Release

Then my shooting procedure will look like this:

1. Half press: 'Enable sync' gets disabled, camera focuses, LCD still show the image
2. Full press, 'Enable sync' gets enabled, LCDs turn to black (enter sync procedure)
3. Release: Take the image

I can use a microcontroller to generate pulses for the 3 states, but I don't know how to enable/disable the 'Enable sync' in the CHDK settings.
Since in the past I did some CHDK programming in C, I prefer to do it in C (and don't want to do it using scripting with basic)

Hope it is clear what I need, thanks for any idea...

« Last Edit: 15 / April / 2015, 16:00:26 by mr.burns »

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2 x Powershot S110 103a

msl

1280
A720 IS, SX220 HS 1.01a

Re: Need 3 states for shooting (S110)

« Reply #1 on: 15 / April / 2015, 16:22:29 »

You can set most of the CHDK menu options via script. Read more about set_config_value() => http://chdk.wikia.com/wiki/Script_commands#set_config_value . Check core/conf.c for the right ID.

msl

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waterwingz

12138

Re: Need 3 states for shooting (S110)

« Reply #2 on: 15 / April / 2015, 18:20:44 »

Quote from: mr.burns on 15 / April / 2015, 15:38:48

To get synced stereo images I enabled 'Enable remote' and 'Enable sync' under the 'CHDK Settings'. 'Switch type' is set to 'One push'.

Quote

I can use a microcontroller to generate pulses for the 3 states, but I don't know how to enable/disable the 'Enable sync' in the CHDK settings.

I think you are trying to do this the hard way.

You can get exactly what you want if you set the switch type to "Two push" rather than "One push" and everything else is setup as you described. Refer to this diagram from the wiki USB Remote page for the "Two press switch" :

In that mode, the first pulse will lock the focus and exposure. If you then want to shoot, the sync operation starts when you start the second pulse. If you activate the pulse (+5V) for more than about 500 mSec then it will reach the point at which it blanks the LCD display waiting for the second pulse to complete so that it can finish the shot perfectly sync'd.

No microcontroller or programming or changing CHDK setting "on the fly" required. It just works!

Note that you can do the same thing with the switch type set to CA-1 if you actually have a Ricoh CA-1 (or want to emulate it with our micro-controller).

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mr.burns

223

Re: Need 3 states for shooting (S110)

« Reply #3 on: 16 / April / 2015, 05:33:52 »

Hi waterwingz,

thanks for reply, good to still have you here ;-).

OK I can try with the 'Two press switch'.
But I see a problem with that:

1. I pan the camera to get my object into the focus rectangle
2. I press the switch for the first time --> camera focuses --> camera focus finished
3. Now I have only 500msec to pan back the cam to shoot my original image

500msec is not enough to pan back the camera.

So may I should give the 'Ricoh CA-1' a try.
I don't have a 'Ricoh CA-1' but I think I can simulate the pulses with my microcontroller.
But what I guess is that after sending the first 30ms pulse the camera focuses and after focus has finished CHDK jumps to the sync procedure and turns off the LCD. But this I have to try.

BTW

I think the diagram for 'Two push' option is not correct, since the timepoint when the camera is focused/locked is not necessarily the same as button is released (correct me if I am wrong).

« Last Edit: 16 / April / 2015, 07:36:11 by mr.burns »

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2 x Powershot S110 103a

waterwingz

12138

Re: Need 3 states for shooting (S110)

« Reply #4 on: 16 / April / 2015, 08:26:57 »

Quote from: mr.burns on 16 / April / 2015, 05:33:52

OK I can try with the 'Two press switch'.
But I see a problem with that:
1. I pan the camera to get my object into the focus rectangle
2. I press the switch for the first time --> camera focuses --> camera focus finished
3. Now I have only 500msec to pan back the cam to shoot my original image
500msec is not enough to pan back the camera.

That's not quite how it works. The sequence goes like this :

Pan the camera to get the object into the focus rectangle
Press and hold the switch for the first time --> camera focuses --> camera focus finishes (beep?)
While holding the switch in the pressed position, pan the camera back to the original image
Release the switch
Within 1/2 second, press the switch again
Wait at least another 1/4 second
Release the switch again

The camera will focus and set exposure after step 2. At step 5 the camera will start to shoot but will pause right before it releases the shutter (LCD off). At step 7 the shutter is released.

Quote

So may I should give the 'Ricoh CA-1' a try. I don't have a 'Ricoh CA-1' but I think I can simulate the pulses with my microcontroller. But what I guess is that after sending the first 30ms pulse the camera focuses and after focus has finished CHDK jumps to the sync procedure and turns off the LCD. But this I have to try.

If you really want to try using a microcontroller, by all means go ahead. But it's not necessary.

Quote

I think the diagram for 'Two push' option is not correct, since the timepoint when the camera is focused/locked is not necessarily the same as button is released (correct me if I am wrong).

The diagram is perhaps misleading. The exact timepoint at which the camera is focused/locked depends on how long it take the Canon firmware to complete that operation. What the diagram is intended to show is that you need to keep the button pressed the first time until that happens. Note that the diagram shows shooting without sync - the picture takes on the rising edge of the second press rather than waiting for the falling edge (in sync mode).

« Last Edit: 16 / April / 2015, 08:32:44 by waterwingz »

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mr.burns

223

Re: Need 3 states for shooting (S110)

« Reply #5 on: 17 / April / 2015, 02:39:46 »

Hi waterwingz,

I tested now with 'Two Press Switch' and it worked like you explained.
I never was clear about the 'Two pass switch' in the past but now I am,

thanks a lot, that really helped!

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