Minimum Camera for Book Scanning

[blueblazer]

I have been experimenting with smart phone cameras with my scanner and have found the Droid Incredible to work quite well as an 8mp camera. I've found I can scan books up to 8x10 without much issue.

I'm using droid based cameras, do to the ability to fully script the picture taking and sorting process, bypassing any need for mechanical triggers or camera firmware shenanigans and seem to be having some success. Having all your pages fully sorted and ready for cleaning through Scan Tailor as soon as you finish the scan is really quite handy.

You can pick up an Incredible with a bad ESN for around 60$(we don't need it for the cell service after all). You can setup a manual focus using Camera 360 as I have found the auto focus feature really throws you off if you are scanning quickly. As the cost of used smart phones comes down and the camera resolutions come up I believe that this will eventually be the route we take. The HTC Titan II is already up to 16mp($700 but so was the Incredible when it first came out.)

I'm working up my build for you guys as soon as I get the last few kinks worked out.

[Heelgrasper]

One subject that needs to be dealt with is the minimum focus distance (MFD from now) when you zoom.

I haven't thought of it as a problem until yesterday but it seems be a growing problem. My old Canon PowerShot A540 in macro mode have a MDF of 5 cm (2 inches) when not zoomed (W) and 30 cm (12 inches) when zoomed (T). In my experience the 30 cm kicks in as soon as you zoom, not just when you're at full zoom. Without macro mode the MFD is 45 cm (18 inches) for both W and T.

For the newest line of Canon PowerShot A-series cameras that has changed quite a bit. It might have done that long ago but I haven't noticed before.

The Canon PowerShot A810 can serve as an example since it seems to be same for all in the new line. The specifications are ( http://www.usa.canon.com/cusa/support/consumer/digital_cameras/powershot_a_series/powershot_a810#Specifications ):

Focusing Range
Normal: 2.0 in. (5cm) - infinity (W), 3.9 ft. (1.2m) - infinity (T)
Auto: 1.2 in. (3cm) - infinity (W), 3.9 ft. (1.2m) - infinity (T)
Macro: 1.2 in. - 2.0 ft. (3-60cm) (W)

It has to be confirmed but this could mean that if you're book scanning you can't zoom in unless the camera is at least 1.2 m from the platen. Basicly the same seems to be true of a camera like Sony DSC-W570.

So it seems MFD when zoomed is something to look out for. If you can't zoom you might need to able to change the distance between camera and platen more to adjust to different sized books (or live with wasted pixels and lower DPI). And if barrel distortion is a problem when the camera isn't zoomed the only way around might be to build a scanner were the cameras are something like 3-4 feet from the platen.

[jlee]

Hi Folks,

Building my set up and need help on camera selection. Will the Canon ELPH 100 HS work OK? Been trying to find out whether this particular model has SDM or CHDK, but no luck yet. Any one with a guidance on this, please help. Thank you in advance.

John

[Gerard]

http://bit.ly/HPXdzL

the canon cameras have sometimes different names in different countries, see the porting thread how far the development is