8mm film scanner / How many pictures possible per ten seconds?

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8mm film scanner / How many pictures possible per ten seconds?
« on: 25 / September / 2015, 06:20:51 »
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Hi!

I am working on a 8mm scanner, using a dismantled Bolex 8mm camera and a hacked Ixus 55 with macro lens to capture it frame by frame. I am planning an Arduino to move the film and to trigger the camera, then repeat until all 5500 frames are done.

I was curious -

1) how long does it take to take a pic if I don't focus in betweee images (I am working on a 3D printed frame for the scanner, and it'll be very stable)

2) how do I focus it manually? I have made tests and am able to position the macro lens about 10mm away from the film, with the frame filling almost all of the display, then focused with 4x zoom.

Thanks for making my project a lot easier with the CHDK,

Heikki
« Last Edit: 03 / December / 2015, 12:57:43 by reyalp »

Re: How many pictures possible per ten seconds?
« Reply #1 on: 25 / September / 2015, 10:08:01 »
1) how long does it take to take a pic if I don't focus in betweee images (I am working on a 3D printed frame for the scanner, and it'll be very stable)
It varies with camera model but slightly more than two seconds if you focus and slightly less that two seconds if you don't.

There is a script that uses an additional trick that would work in your application.  You might get down close to one second per shot if you use it :
Fast Shooter Intervalometer

A slightly different approach can also be found here :
/Scripts: A fast intervalometer

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2) how do I focus it manually? I have made tests and am able to position the macro lens about 10mm away from the film, with the frame filling almost all of the display, then focused with 4x zoom.
There is a manual focus option in the CHDK overrides menu.   But if you use the first script that I mentioned above, it will only focus when it takes the first shot and then it will use that focus setting for all subsequent shots (i.e. it calls the set_aflock(1) function)
Ported :   A1200    SD940   G10    Powershot N    G16

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Offline reyalp

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Re: How many pictures possible per ten seconds?
« Reply #2 on: 25 / September / 2015, 16:11:17 »
Using shoot hooks and external control with USB remote or PTP, you should be able to shoot quite close to the canon continuous mode shooting rate.

According to the canon specs, this is 2.1 FPS.

You would just set the shutter hook, send a full press, and then block in the shutter hook until the controller signals it's time to take the picture.

edit: I'm not sure if there is a way to do the same thing using normal remote settings. Waterwingz?

Using PTP control chdkptp you could use rsint for this purpose. You'd just need something to feed an 's' to stdin as soon as the frame is in position, and wait for output indicating the download has started to before advancing. This would download the images directly to a PC rather than the camera card. Note chdkptp doesn't run on  Arduino, but it can be run on rasberry pi or other SBCs that run a normal linux distro.

edit:
These old cameras have pretty slow USB, so saving over PTP may be slower than using a card.
« Last Edit: 25 / September / 2015, 16:18:14 by reyalp »
Don't forget what the H stands for.

How many pictures possible per ten seconds?
« Reply #3 on: 25 / September / 2015, 16:46:43 »
edit: I'm not sure if there is a way to do the same thing using normal remote settings. Waterwingz?
That's essentially what the latest version of kap_uav.lua does.  Hadn't thought about making it a built-in option. No reason not to I guess.


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edit:
These old cameras have pretty slow USB, so saving over PTP may be slower than using a card.
At that point, you might as well just use one of the two scripts I linked? Suitably modified to shoot on a signal from the Arduino of course.
« Last Edit: 25 / September / 2015, 17:29:43 by waterwingz »
Ported :   A1200    SD940   G10    Powershot N    G16


Re: How many pictures possible per ten seconds?
« Reply #4 on: 26 / September / 2015, 10:44:16 »
Hi all,

thank you very much for these answers! They help me along very nicely.

This is a great site all in all!


Using the set focus
« Reply #5 on: 29 / September / 2015, 10:42:07 »
Hi all,

I have an Ixus 55, and I am trying to shoot pictures at extreme macro level (about 1 cm or less away from the target, which is a frame of 8mm film). I found the Override Subject Distance feature, and have been abe to set it to a value of 25, but when I start to shoot and press half trigger, it focuses again.

I don't think I have found the AF lock yet - does anyone know where it is?

"Depending on camera, you may need to activate AF lock for subject distance override to work. You may also need to disable any camera function that tries to alter the focus (such as "Servo AF" or "Continuous AF")."

Thanks again!

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Offline reyalp

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Re: Using the set focus
« Reply #6 on: 29 / September / 2015, 16:52:17 »
According to the code, this camera needs either AF lock or set_mf() script call for focus overrides to work.

You can set AF lock in the canon firmware by half pressing the shutter and then pressing the focus mode button. In chdk script, you can use the set_aflock() function.
Don't forget what the H stands for.

Re: Using the set focus
« Reply #7 on: 30 / September / 2015, 01:23:54 »
Fantastic stuff, thank you very much!

Is the 0 value the 3cm as mentioned in the spec of the camera? And what is the step?

I'll show you what I currently have - I have added a macro lens, usually sold for mobile phone use, and I can get a 4.8 mm x 3.5 mm frame from a 8mm film to show like this attached image.

Cheers,

Heikki


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Offline reyalp

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Re: Using the set focus
« Reply #8 on: 30 / September / 2015, 17:04:28 »
Is the 0 value the 3cm as mentioned in the spec of the camera? And what is the step?
The value is in mm. Whether that is measured from the sensor, lens, or somewhere else may not be well specified.

You can use get_focus() or the DOF calculator OSD to see what value the camera thinks it's using at various distances.
Don't forget what the H stands for.

Re: Using the set focus
« Reply #9 on: 02 / October / 2015, 00:14:53 »
Very good, I will install and test some more. Many thanks for your kind answers!

 

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