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

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Offline heikkiH

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Re: Hooking an Arduino into the CHDK USB Remote, and file save location
« Reply #30 on: 04 / November / 2015, 01:36:07 »
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Hi guys,

this is the setup diagram. The other picture is to show you the real thing, and a video of the film gate in operation is at https://www.youtube.com/watch?v=3EMSqx0t4Kw

The film gate is from a vintage camera bought on eBay. It has a crank-piston like hook that advances the film a frame at a time. This crank is rotated by the first servo running at one revolution per two seconds.

The hook, at its most extended, triggers the film gate microswitch.

That sends a signal via the USB remote to the camera, which grabs a picture. My current remote only has two wires, it is built from scratch.

The servo then moves the film one frame ahead.

When the film travel microswitch opens, it causes the film takeup servo to run slowly until the switch closes again.

The status now:

Film gate servo runs and film travel works.

Trigger microswitch works and grabs pictures.

Current challenges:

1) image space - if I were able to save pictures on the computer, I could shoot at the max resolution. The sheer number of frames in a 4 minute film passes the 5,000 mark, hence making it necessary to slash resolution to its lowest, or, pause the process until I can move the images from the card.

2) focusing to the sharp focus and zoom at 4.0x, then stabilising those for the rest of the operation.

Do I have it right when I think that if I were to install the film trigger microswitch to a full USB cable, I could use chdkptp to store images on the computer?

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Offline reyalp

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Re: Hooking an Arduino into the CHDK USB Remote, and file save location
« Reply #31 on: 04 / November / 2015, 17:00:41 »
Very nice work :)
Quote from: heikkiH on 04 / November / 2015, 01:36:07
1) image space - if I were able to save pictures on the computer, I could shoot at the max resolution. The sheer number of frames in a 4 minute film passes the 5,000 mark, hence making it necessary to slash resolution to its lowest, or, pause the process until I can move the images from the card.
Unless there is some special reason to use the ixus55, you might consider just getting a camera that supports SDHC. You should be able to find one pretty cheap.

If you do want to save the images over USB, I think controlling both shooting and transfer using chdkptp as nafraf and waterwingz suggested is probably the way to go. However, you may need to stop and reboot the camera every thousand images or so: Every powershot up to now has a limit that stops USB from working if it thinks there are too many images (approx 1000 according to the manual). This will probably still happen if you use CHDK to save over USB or download and delete the files. If the reboot is needed, it should be possible to automate as part of your script.

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2) focusing to the sharp focus and zoom at 4.0x, then stabilising those for the rest of the operation.
Of you use continuous mode or keep half press held, the focus should not change between shots. If you use a chdkptp based process, you can do this with the rsint command.

To set the focus distance in the first place, ixus55 supposedly needs either set_mf or set_aflock before you can use set_focus. It's possible that this isn't correct, you should experiment to find out what actually works. Assuming one of these methods work, you should be able to just find the right distance for set_focus with a little trial and error.

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Do I have it right when I think that if I were to install the film trigger microswitch to a full USB cable, I could use chdkptp to store images on the computer?
I think it should be possible. The usb_force_active function was made for this kind of application. It should work on ixus55 if you use CHDK 1.4, it is not implemented for this camera in the 1.3 stable branch.

You will also need to implement something to trigger the actual download. You may be able to use write_usb_msg for this.
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Offline heikkiH

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Re: Hooking an Arduino into the CHDK USB Remote, and file save location
« Reply #32 on: 05 / November / 2015, 14:55:27 »
Thanks muchly :)

I am using the 55 because I happened to have one handy and didn't want to invest anything. I do have a D700 too, which I will take into use at a later stage, but for now the 55 will do nicely.

I am happy to report this:
That is largely due to the kind assistance I have from here. I see now that I get around 15 frames a minute, which means I will scan a 4 minute film in just five hours :P That's fine, time is not the issue here.

The focusing still needs to be done, but I take it that I can read the focus from the screen when I take the first test picture, then write a script that uses it in the long run. I haven't got the focusing to stay put yet, but that will also give a shorter time between images. The switch needs to remain closed for 500 ms, or, I should be able to send it from the Arduino.

Stay tuned :)
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Offline heikkiH

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Re: Hooking an Arduino into the CHDK USB Remote, and file save location
« Reply #33 on: 12 / November / 2015, 11:34:32 »
It's working.

Here's a link to the first 15 seconds of movie I have captured using the rig shown in this thread. As you can see, the remaining thing is getting the backlight more even, but that's about it - small jumps are to be expected in 8mm, and I will not iron them out.

See
When I get the adapter for the battery, I can start shooting in earnest.

Many, many thanks to all who helped me along!
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Offline axman

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Re: Hooking an Arduino into the CHDK USB Remote, and file save location
« Reply #34 on: 14 / November / 2015, 13:15:56 »
Hei Heikki

I'm doing vaguely similar project.  Using Arduino, customized usb cable and these mechanical relays from Pololu;

https://www.pololu.com/product/2480

If you have the requirement to activate some kind of switch manually, the relays work great and the Ardu code is pretty simple.

Also, I agree with what the other guys have said, eg chdkptp is still the easier way to go to get the data off the SDcard.

B/r
alex
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Offline heikkiH

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Re: Hooking an Arduino into the CHDK USB Remote, and file save location
« Reply #35 on: 17 / November / 2015, 02:06:41 »
Thanks for the link :) I have the system running now so I'll work with what I have for now. Your solution is probably more elegant though.
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Offline heikkiH

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USB remote and focusing just once
« Reply #36 on: 18 / November / 2015, 11:25:45 »
Hi all,

you may remember my 8mm film scanner project, which is getting very near to completion. Just one more question:

When I have the USB hooked, and I do a half-press to get the focus for the first shot, I get a good photo. Is there a way for this focus to stay put, with no autofocus in between, because the film I scan remains very securely in place, and there is no need for refocusing?

Cheers

Heikki
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Offline waterwingz

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USB remote and focusing just once
« Reply #37 on: 18 / November / 2015, 12:12:52 »
Most Canon P&S models allow you to lock focus from the camera keypad.  If you are using a script, the set_aflock() function will do the same thing.  The camera does one focus operation and locks when the AFL button is pressed or the function called so you need to have it mounted properly when you do that.
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Offline reyalp

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Re: USB remote and focusing just once
« Reply #38 on: 18 / November / 2015, 21:06:32 »
Quote from: heikkiH on 18 / November / 2015, 11:25:45
When I have the USB hooked, and I do a half-press to get the focus for the first shot, I get a good photo. Is there a way for this focus to stay put, with no autofocus in between, because the film I scan remains very securely in place, and there is no need for refocusing?
Does exposure need to adjust between shots?  If not, I'd suggest keeping half press held down and clicking full press (or using a script to simulate this with the remote) or using continuous mode and shoot hooks. This will give you a faster shooting rate than using AF lock, and the focus won't change between shots.
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Offline waterwingz

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USB remote and focusing just once
« Reply #39 on: 18 / November / 2015, 21:20:37 »
Quote from: reyalp on 18 / November / 2015, 21:06:32
Does exposure need to adjust between shots?  If not, I'd suggest keeping half press held down and clicking full press (or using a script to simulate this with the remote) or using continuous mode and shoot hooks. This will give you a faster shooting rate than using AF lock, and the focus won't change between shots.
All good ideas if you are using a script.  But if you just want to use the built-in USB remote functionality, then setting Canon AFL from the keypad is the easy to go.

Edit : probably depends on whether the camera can shoot as fast as the film can shuttle forward?
« Last Edit: 18 / November / 2015, 21:33:48 by waterwingz »
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