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

Portable Build Lighting Question

All about lighting. LED, CFL, Halogen, Other? Questions and info about lighting go here.
DrCheap
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Re: Portable Build Lighting Question

Post by DrCheap » 07 Aug 2012, 09:49

I am finding that the 10w LED flood is not generating enough light for my cameras. This may be in part due to less than perfect cameras, but my images have a good deal of color noise due to insufficient lighting. I am going to start looking at swapping out the 10w LED for something in the 20-30w range instead. The 10w LED floods are really equivalent in lumen output to about one 60w incandescent.

Can anyone think of a reason NOT to use higher lumen value lights instead? (Assuming I can fit them into the rig). I'm using museum glass so reflections have not been an issue at all, but I definitely need more light.

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daniel_reetz
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Re: Portable Build Lighting Question

Post by daniel_reetz » 07 Aug 2012, 09:58

I trust your measurements here, but can you post a JPG straight from the camera, looking at a white sheet of paper, so we can see what settings the cams are choosing via the EXIF data?

And no, there's no reason not to upgrade. The kits that Rob produced had a plate which could accept two incandescent bulbs in cheap holders.

DrCheap
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Joined: 07 Jan 2012, 19:27
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Re: Portable Build Lighting Question

Post by DrCheap » 07 Aug 2012, 11:21

Thanks for the quick reply and offer of help. I will nab shots of blank white pages when I get home tonight and post them, but in the meantime, my flickr portfolio has a JPG of a book page and a TIFF produced from the CR2 RAW: http://www.flickr.com/photos/84319956@N ... 916182714/

I'll post JPG of a blank solid white page tonight.

Thanks again,

DrCheap
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Re: Portable Build Lighting Question

Post by DrCheap » 07 Aug 2012, 18:08

Two JPGs attached.

0789 is a clean fresh white sheet of paper with the black base visible at the edges.
IMG_0789.JPG
0788 is the same sheet of paper with optical zoom set to only display the white.
IMG_0788.JPG
Thanks for any advice and help on this.

I can also provide CR2 RAW and TIFFs made from RAW if those would be helpful.

Current lighting is a standard 10w LED flood -- the one recommended above in this thread.

DrCheap
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Joined: 07 Jan 2012, 19:27
E-book readers owned: pdf
Number of books owned: 750

Re: Portable Build Lighting Question

Post by DrCheap » 08 Aug 2012, 16:54

Oh, and just fyi, I am not using any JPGs in the production of the scanned books -- I am using TIFFs from the camera RAW (cr2) files, as they are lossless and uncompressed. So the camera settings themselves, I believe, won't have any effect on my images.

DrCheap
Posts: 48
Joined: 07 Jan 2012, 19:27
E-book readers owned: pdf
Number of books owned: 750

Re: Portable Build Lighting Question

Post by DrCheap » 10 Aug 2012, 22:27

I tripled the amount of light coming in and am getting MUCH better results now. Nearly perfect OCR and my final PDFs are gorgeous.

I'll try to post a copyright-free sample soon(tm) along with pics of the rig.

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daniel_reetz
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Re: Portable Build Lighting Question

Post by daniel_reetz » 11 Aug 2012, 13:38

Thanks for following up on this. It's been hard for me to get to the forum the last few days.

I'm looking at your photos and I see two things wrong. One is that the exposure value seems to be wrong. It's white paper, right? So the images should be exposing for white paper. Does your camera have an exposure value compensation option? It's usually a little +/-1 option in a square. These images should be almost white.

To that end, if you set your settings manually (ignoring the compensation), you should only have to adjust one parameter to get good exposures with the old light. Your current settings are

ISO 400 (fine)
Aperture F4.51 (odd value, may be because of zoom, are you using it?)
Shutter speed 1/79sec.

You should change that to
ISO 400
Aperture F4.51 (or as small a number as possible, F2 would be great)
Shutter 1/30sec.

Changing the shutter speed will more than double the available light. 1/30 is the "slowest" shutter speed you want to use to get a good exposure.

Regardless of using more or less light you should be getting closer to white with your final images so please consider changing your exposure compensation even with your new success.

DrCheap
Posts: 48
Joined: 07 Jan 2012, 19:27
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Number of books owned: 750

Re: Portable Build Lighting Question

Post by DrCheap » 11 Aug 2012, 16:24

Thanks, I will see what I can muster. I'm using cheapo A480s with CHDK, but there is a little odd focus behavior in programmable mode. When in AUTO mode the focus will find the text on the page and set that as the focal area -- all good. When in programmable mode, no matter how I set the focus mode it uses the middle 20% of the page, which means title pages and pages with only a few lines at the top are always out of focus. If I can get that resolved, then I will set ISO, exposure, and aperture as CHDK allows.

Thanks again for the help.

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daniel_reetz
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Re: Portable Build Lighting Question

Post by daniel_reetz » 11 Aug 2012, 20:13

You could consider setting the focus once and locking it - since you're using one of the new scanners, which fix the distance between the platen and the camera, you should only have to focus once, ever.

Gothiczartan84
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Re: Portable Build Lighting Question

Post by Gothiczartan84 » 17 Apr 2013, 07:36

http://www.amazon.com/Table-studio-ligh ... ghting+kit

how about these?

I'm planning to make a simple DIY Book scanner by using a clear flat board which would be glass and a flat wooden board with two metal bars to hold up the glass.

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