my simplistic book scanner setup

[nilsb]

Dear all,

I am new to this forum. After I found this website by coincidence and got aware of the fact that there is a whole community of working on simple and cheap solutions to scan books I was quite interested. So I was thinking about my solution.

I wanted to see some results fast. So I was thinking about a very simple setup. The necessary parts are from my point of view of course the
* glass pane
* camera
* light
* and a remote shutter

I want to show you a few pictures how I did my first setup. And already my first two books.

The glas pane is actually of plexiglass/acrylic glass supported by wooden pieces each side fixed by a bar clamp to a table

from top

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For the light on from two sides I took two 500W halogen spot lights. Not because I specifically chose them but because I found them in my cellar.

light from left

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light from right

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The camera is a canon EOS 400D. It is just lying flat on the floor and I have attached a simple tripod only for better support and so that it doesn't slide away to easyly.

camera

CIMG2997.JPG (65 KiB) Viewed 1686 times

The remote shutter is a Staples "That was Easy" Button. I found a way to connect it to a 2,5 jack and this is a perfect way to remotly take a picture.

remote shutter

CIMG2999.JPG (65.97 KiB) Viewed 1686 times

The setup of the camera took quite some time. Also I still need to find the right settings. But when the setup is done I found that flipping of the pages and taking the picture was quite fast. I managed to take about 12 pictures per minute.

Comments welcome.
Nils

[daniel_reetz]

I love this kind of setup - knocked together from whatever is at hand. Could you comment on the 400D as a digitizing camera? Did it work as you expected, any unexpected problems?

Thanks for sharing this with us, and welcome.

[nilsb]

Hi Daniel,

I like to see your video on diybookscanner.org! And I would like to express my respect and appreciation for people like you who are putting an idea into effect and setting up a complete new community. Great work. Thank you!

Coming to your question about the camera:

First I thought about using my compact camera from Casio. But it seems there is no way to simply remote control the shutter. So I had the Canon EOS 400D available and found out that it's rather easy to build a simple foot switch for that. And it works really good. About the camera itself I cannot say much. I am not a very skilled photographer so I still need to find out the right settings. I am trying to go through relevant discussions on this forum but it needs some time. So my problems were not so much lying on the camera then on the fact that I just started and have to get some experience.

My questions to the community would be:

How do you find out the right setting for the camera?
Which setting for the autofocus is the best?
Could you think of a case where manual focus works even better?

I feel like trying out my setup on simple testcases (like a sheet with half white half black print) and get the average colour value for the white and the black part in order to find the setting with the best ratio between white and black (Signal-to-noise ratio).

So maybe there should be some simple testcases (with simple test pictures). Then one should take a series of pictures changing only one of the parameters and have a clear value as result for each of these pictures/parameters.

Which are the relevant parameters?

Thanks
Nils

[Gerard]

Which setting for the autofocus is the best?
Could you think of a case where manual focus works even better?

auto focus has sometimes problems with (nearly) blank pages and the focus search time slows you down, also you have always open your ears for the focus found sound, the search time is not always the same,

with manual focus the workflow is faster, but the distance at the beginning of the book and the end is not the same (depends on the book thickness) i don't know is this makes a huge difference (and not every book scanner design has this problem)

[nilsb]

Thank you Gerard. Makes sense what you say - I also noticed that sometimes the focus doesn't work on a simple white sheet of paper.

But how do I set it manually? I remember with the old analog SLR (Spiegelreflex) camera there was something like an optical element in the viewfinder where I had to point to a line and adjust the focus so that the two parts of the line do fit together. But how is it with digital SLRs? Do I have to decide by my own eyesight if its focused?

Thanks
Nils

[daniel_reetz]

nilsb, I'll answer more fully sometime soon, but one approach with cameras like this is to focus using the autofocus feature, and then there is a button somewhere to "lock" the autofocus in place. Check your manual for something like "AF lock" or "AE/AF Lock".

[Alan Shutko]

On your DSLR, you can set the camera to manual focus and focus it until it looks good. When you are in focus, if you half-press the shutter, the focus confirmation light will come on. (On other DSLRs, you might have arrows that tell you which direction to switch focus.)

In my build I used fixed focus, because some pages didn't have contrast in the right spot so it wouldn't focus. I wasn't worried about the difference in distance from the camera... I closed down to f/8 and that gave me enough depth of field. On a thicker book, it might be worth checking focus every 10-20 pages. I'll have to experiment.

[Alan Shutko]

So, how do you figure out the settings?

In general, you want the lowest ISO you can get away with. Since your camera is on a tripod, it can handle a slow shutter speed.

To maximize sharpness, you generally want an aperture somewhere in the middle of its range. (You can google your specific lens to find out where it's sharpest.) So I set those, then let shutter speed determine how much light gets into the camera.

You should probably shoot RAW if possible, and process those into TIFFs. (Or shoot TIFF if that's an option.) JPEG compression is not friendly to high-contrast stuff like text. But it might not be too much of a problem for you at your resolution.

[kempelen]

To maximize sharpness, you generally want an aperture somewhere in the middle of its range.

Nice to know, thank you. I used the same setup as you explained, but I don't know why, I am just guessing.

I also had problems with center point AF (off-focus pages when there was only a little text), but the camera has other modes, e.g. 3-areas AF, which covers the page well.

White balance seems to be very important too. My guess is that cameras without "manual wb" and/or "wb fine tuning" are not good for this purpose. Opinions? (Manual WB gives much better result for me than any available preset mode.)

For Image Stabilization, I read somewhere that IS will do more harm than good if used on tripod or other fixed stand. (It will notice minor movements and overcompensate.) Opinions?

[Alan Shutko]

For white balance, I'd say just use whatever is working out best for you with your particular lights. It's something that you can fairly easily fix in post, but it's faster if you don't need to fix it.

Image stabilization won't help you on a tripod. From what I've read, it won't necessarily hurt you, though... A lot of cameras/lenses are smart enough to turn it off automatically. If you have a switch to turn it off, turn it off.