Daniel Reetz, the founder of the DIY Book Scanner community, has recently started making videos of prototyping and shop tips. If you are tinkering with a book scanner (or any other project) in your home shop, these tips will come in handy. https://www.youtube.com/channel/UCn0gq8 ... g_8K1nfInQ

One camera does not fire or does so late

Everything camera related. Includes triggers, batteries, power supplies, flatbeds and sheet-feeding scanners, too.
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StevePoling
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One camera does not fire or does so late

Post by StevePoling » 10 Jan 2010, 00:25

I bought Dan's electronics package several months ago. And I just finished digitizing my first book. I noticed that on several occasions I pushed the button and just one camera would snap, or the camera that didn't snap the first time would hesitate several seconds then snap. And sometimes both cameras nicely snapped in synchrony. Has anyone else seen this malfunction? Is there something I'm doing wrong?

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daniel_reetz
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Re: One camera does not fire or does so late

Post by daniel_reetz » 10 Jan 2010, 01:08

Are your cameras autofocusing? Is one not getting good focus?

StevePoling
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E-book readers owned: SONY PRS-505, Kindle DX
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Re: One camera does not fire or does so late

Post by StevePoling » 10 Jan 2010, 01:53

I just went through that camera's imagery. yeah, it's failing to focus on some pages. I'm running the Canon A590 and I suppose there's something obvious in the camera setup that I've goofed up.

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daniel_reetz
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Re: One camera does not fire or does so late

Post by daniel_reetz » 10 Jan 2010, 10:24

Most everybody's doing manual focus now for this very reason. Set your aperture as wide open as it gets, manually focus the cams, and then leave 'em there. They'll fire faster and more reliably.

There's a lot of info about manual focus diffused throughout this forum. I hope fbonomi comes back someday so we can sort it all into a really kick-ass wiki article. Also Rob and Spamsickle have long been MF advocates.

StevePoling
Posts: 290
Joined: 20 Jun 2009, 12:19
E-book readers owned: SONY PRS-505, Kindle DX
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Re: One camera does not fire or does so late

Post by StevePoling » 10 Jan 2010, 22:39

I've come to realize in the last couple days that I'm a complete ignoramus about photography and that I've got to figure out howto at least understand the vocabulary, then understand which settings i need and howto set up my cameras to them.

spamsickle
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Re: One camera does not fire or does so late

Post by spamsickle » 11 Jan 2010, 03:12

I'm using manual focus, but I sometimes have one camera fail to fire. It happens maybe one time out of 500 shots. I don't know what causes it, but for my workflow the easiest time to take care of it is while I'm shooting. I just reshoot the page, and delete one of the extra images before I continue. I have to drop out of CHDK ALT mode briefly to delete the picture, but I've found that I don't need to stop the script and then stop ALT -- just push the "PRINT" button to stop ALT mode, use the menu to delete the extra picture, then push the "PRINT" button again to restart ALT mode with the script already running.

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daniel_reetz
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Re: One camera does not fire or does so late

Post by daniel_reetz » 11 Jan 2010, 09:12

great tip, spamsickle.

SDM is designed to maximally synchronize cameras. I read some discussions with the author where he said it's hard to get them to sync up on one pulse but easy to get them to sync after 2, because you know the second pulse is coming. On my portable scanner; I have arduino hold the line high for a full 1:5 seconds, and I've yet to have a problem, except that it feels a little slow to me.

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