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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: USB remote and focusing just once
« Reply #50 on: 25 / November / 2015, 11:58:27 »
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Thank you very much again- you seem to have taking this issue to heart :) !

It is indeed a real vintage 55. I have an 95 as well, and if this doesn't work, I'll just transfer to that one and try again. But I will test this first thing in the morning and tell you the results.


Cheers,

-h.
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Offline reyalp

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Re: USB remote and focusing just once
« Reply #51 on: 25 / November / 2015, 13:26:05 »
Quote from: heikkiH on 25 / November / 2015, 07:54:47
I have to check for the AFL letters tomorrow, the scanner is being built at our 3D lab at the University.

I used the ALT key, then loaded the script from the list.
Just in case: In CHDK, the script menu just selects the script. To actually run it, you need to click the shutter button in alt mode.
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Offline heikkiH

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Re: USB remote and focusing just once
« Reply #52 on: 25 / November / 2015, 14:28:10 »
Your way of pointing out to me that I may have been an idiot is very kind and considerate :D But it is very likely I didn't follow procedure with the script.

As for the download - I copied the one that was in a messag previously and will now download yours, then test it in the morniong when I get to the lab. I can't wait to see how this will work out.

I remain in your debt!

cheers

-h.
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Offline waterwingz

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Re: USB remote and focusing just once
« Reply #53 on: 25 / November / 2015, 14:51:09 »
Quote from: heikkiH on 25 / November / 2015, 14:28:10
Your way of pointing out to me that I may have been an idiot is very kind and considerate :D But it is very likely I didn't follow procedure with the script.
Looking at the picture you posted of your image capture jig, it seems to to be pretty solid.  So you should be able to set a fixed manual focus distance and just use that forever?  Do away with all the AFL stuff and fidgeting until you get a good focus at startup?   

If that works,  I can add code to the script that lets you pick the focus distance from the script's parameter menu and just use that value forever. 

Alternatively,  if you want to go back to not using a script,  set the  Overrride Subj. Dist. [On] [ 25] in the CHDK Enhanced Photo Operations menu,  where 25 is the distance in mm you want to focus at.  You might have to play with this to get the best exact focus.



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As for the download - I copied the one that was in a messag previously and will now download yours, then test it in the morniong when I get to the lab. I can't wait to see how this will work out.
You will know that the script is running because it will print a new status message in the "console" area each time you press the shutter or "Func/Set" button.
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Offline heikkiH

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Re: USB remote and focusing just once
« Reply #54 on: 27 / November / 2015, 01:06:31 »
Okay, this is the status now:

I downloaded the script and it works really well. It keeps the focus still and tells me it's working. The only issue is that it seems to interfere with the triggering of the shooting by Arduino - the system is missing frames and sometimes grabs one in between frames.

I then unloaded the script and fiddled with the film gate speed, and the delays in the Arduino, and managed to give the system enough time to refocus and shoot. It gave me 732 pictures until the battery went dead, and of those, two were unfocused.

So now I will try the script in conjunction with the new timing and see if this is the ultimate solution. This will have to wait until Tuesday but I will report the results as soon as I get some.

While I am here - if the AC adapter I ordered from China is permanently lost in transit, I may print a battery lookalike and wire it myself. There are three poles on the battery, what is the third for? And if I regulate voltage to 3.7V, it should run just fine? I have a 5V adapter and I can work that into 3.7 no prob.
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Offline waterwingz

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Re: USB remote and focusing just once
« Reply #55 on: 27 / November / 2015, 08:33:15 »
Quote from: heikkiH on 27 / November / 2015, 01:06:31
I downloaded the script and it works really well. It keeps the focus still and tells me it's working.
Progress!

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The only issue is that it seems to interfere with the triggering of the shooting by Arduino - the system is missing frames and sometimes grabs one in between frames.
Does it actually miss frames or does it just take too long to shoot sometimes and thus appear to grab between frames?

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I then unloaded the script and fiddled with the film gate speed, and the delays in the Arduino, and managed to give the system enough time to refocus and shoot. It gave me 732 pictures until the battery went dead, and of those, two were unfocused.
Refocusing at each shot will reduce battery life of course.

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So now I will try the script in conjunction with the new timing and see if this is the ultimate solution. This will have to wait until Tuesday but I will report the results as soon as I get some.
As you have an Arduino controller,  you could attach a photosensor to one of the camera LED's and let the CHDK script blink the LED each time it completes a shot.  The Arduino could then detect that blink and use it as a signal to advance the frame.

One other minor worry.   The logic in your SD card will periodically pause to allow it's internal the SD card memory allocation logic to "wear level" the card.  We did a lot of work studying this last year - you can pick up the jist of the conversation starting at this point in another thread :  http://chdk.setepontos.com/index.php?topic=10822.msg116342#msg116342  :  finding that this occurred about every 1000 writes to the card and that it added 2 to 5 seconds to the time to the shot taken after the ~1000 write (on the particular SD card being tested).  We were flogging the card pretty hard with both image and many log file writes so it might not be a big issue with normal shooting.  But if you hit this, there is not much you can do unless you have a feedback mechanism like I described above.

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While I am here - if the AC adapter I ordered from China is permanently lost in transit, I may print a battery lookalike and wire it myself. There are three poles on the battery, what is the third for? And if I regulate voltage to 3.7V, it should run just fine? I have a 5V adapter and I can work that into 3.7 no prob.
That will work well so long as your adapter & regulator can source at least 1.5 amps. Theses cameras draw a lot of current when you shoot.  The third terminal (usually the middle one) connects to an internal battery thermistor. It's used to measure battery temperature during charging - LiPo batteries tend to explode if charged incorrectly so the temperature cutout is a safety mechanism used during charging.  You don't need it if you make a dummy battery.
link :  DIY dc battery coupler for a Canon
link :  3D PRINTED CAMERA BATTERY EMULATOR
« Last Edit: 27 / November / 2015, 10:15:47 by waterwingz »
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Offline heikkiH

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Re: USB remote and focusing just once
« Reply #56 on: 27 / November / 2015, 10:57:00 »
Hi again.

I looked at it for quite a while and it actually misses shots ie. doesn't do anything. I think it is a timing issue between the script and the Arduino program, because when I took it off and adjusted the Arduino timing, I got good shots at 22 shots a minute (which is fully acceptable by the way, I am not in a hurry).

So what I will do now that I have the perfect timing on the Arduino, I will restart the script too, and see if it plays nice with the Arduino.

I'll be sure to post the final video when I get one, but here's how it works today. The only thing I yet have to add is the second servo with switch to run the film takeup spool.

https://www.youtube.com/watch?v=QKi8-18OYLU&feature=youtu.be&a
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Offline waterwingz

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Re: USB remote and focusing just once
« Reply #57 on: 27 / November / 2015, 12:03:29 »
Quote from: heikkiH on 27 / November / 2015, 10:57:00
I looked at it for quite a while and it actually misses shots ie. doesn't do anything. I think it is a timing issue between the script and the Arduino program, because when I took it off and adjusted the Arduino timing, I got good shots at 22 shots a minute (which is fully acceptable by the way, I am not in a hurry).
22 shots a minute is just under 3 seconds a shot.  I would not expect your camera to be able to shoot and save images much any faster.  The upper limit would be 30 shots a minute at best.

The script can be tweaked to shoot more quickly when the Arduino signal it.  reyalp's script fragment did just that but I changed it (to make the console more usable) on the assumption that calling the shoot() function with AFL locked would be fast enough.  Modified version attached.
« Last Edit: 27 / November / 2015, 12:06:09 by waterwingz »
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Offline reyalp

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Re: USB remote and focusing just once
« Reply #58 on: 27 / November / 2015, 17:16:11 »
Quote from: waterwingz on 27 / November / 2015, 12:03:29
22 shots a minute is just under 3 seconds a shot.  I would not expect your camera to be able to shoot and save images much any faster.  The upper limit would be 30 shots a minute at best.
According to canon specs, the ixus55 was capable of ~2.1 FPS in continuous mode:
https://www.usa.canon.com/internet/portal/us/home/support/details/cameras/support-point-and-shoot/powershot-sd-elph-series/powershot-sd450/powershot-sd450/

Under ideal conditions, I would expect heikkiH's setup should be able to get something close to that. These old cams actually had better continuous rate than most modern low end cams. The holding half press / clicking full might give a similar rate to continuous, or might be slower depending on the cam.

However, as waterwingz suggested this would probably require feedback to avoid missing frames due to the occasional slow shot would result in missing frames. The raw hook would be a logical place to put this, since the exposure is finished at that point the film can be advanced while the jpeg is being processed.

One other thing that occurs to me is I'm not clear what kind of signal heikkiH's setup is actually producing, i.e. does the switch open or close when the film is in position, and is it momentary or does it stay until the film is advanced again? is_key remote seems to count at the end of a low->high->low cycle.
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Offline waterwingz

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Re: USB remote and focusing just once
« Reply #59 on: 27 / November / 2015, 18:30:33 »
Quote from: reyalp on 27 / November / 2015, 17:16:11
According to canon specs, the ixus55 was capable of ~2.1 FPS in continuous mode:
True.  But continuous mode is not very useful if you want to control when each shot actually happens. Unless you are using a script sophisticated enough to use RAW hooks of course. 

Do we know for sure that continuous mode goes past the RAW hook in every camera?  I seem to recall an issue with the SX50's burst / continuous mode working differently with some shooting functions than normal shooting for example.
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