I'm looking for a digital camera capable of capturing text images at the National Archives. The documents are original Civil War documents. The shooting conditions are normal ambient overhead lighting with a desk lamp at each research station. Flash photography is not permitted.

Thank you,

Tom Schneider

-- Tom Schneider (antietam@erols.com), August 29, 1998

Answers

The tough part with this one will be getting the resolution you need to preserve the text. I doubt any of the low-end digicams will give you enough pixels for that. The Kodak DC260 has a time-exposure mode that will let you take shots as long as 4 seconds, so it could clearly handle the low-light condition, if the resolution were enough. (While many have complained about the JPEG compression on the DC260, it does quite well with high-contrast images.)

For the maximum in resolution, albeit at a MUCH higher price, you may want to look at the scanning camera backs for pro cameras. PhotoPhase makes the Phase I back in a variety of models, and Dicomed has a scanning back for 4x5 cameras. (I think at least one model of the Phase I fits 220-film camera bodies.) These are big-ticket items, running $10-20K, but the resolution is like that of a scanner. These operate as "tethered" devices, but the Dicomed comes with a "field pack" that contains a hard drive, and can be controlled via a PowerBook. Leaf Systems makes a lower-end scanning camera (the Lumina), but I don't know if they're still selling it, or if it would have enough low-light sensitivity to do what you want.

-- Dave Etchells (web@imaging-resource.com), August 29, 1998.

I agree with Dave, except to say that a megapixel is plenty for copy work like this. I'll assume that if you were making *the* digital copies of these documents you'd be able to use a flatbed or drum scanner, and that since you are restricted to their carefully filtered light you are just a researcher who wants to refer to these documents outside the library.

Given that assumption, I did some tests with my Oly D-600L. At the widest point, its zoom is 36/2.8 (35mm equivalent focal length). That means you can take a picture of a ~1 foot square area from about 1.5 feet away. Using a desk light I took pictures of a quarter of a sheet of newspaper (about 1' square) and looked at them on my 17" monitor. Even handheld regular newsprint is easily legibile across the whole page. On a tripod, taking care to get the document flat, you can even venture to read classified ad sized print, if you had to (a tool like photoshop to increase contrast and sharpen helps).

If you do use a digital camera, make sure you get one that can focus on a full sheet *without* macro mode. Most cameras are going to stop down the lens for greater DOF on macro shots, and that will eat your light.

-- Ben Jackson (ben@ben.com), August 31, 1998.

I got cought up in my testing and forgot to point out that there are megapixel cameras with fixed focal length lenses which will be both cheaper and faster (higher light sensitivity). One obvious example is the Oly D-340L. Avoid cameras which don't really have a million plus pixel CCD, such as the Kodak DC-120 and the Agfa 1280.

-- Ben Jackson (ben@ben.com), August 31, 1998.

Tom -

I bumbled around for six months with a similar problem (except that I am allowed to use lights) to your need to shoot at the National Archives. If you still haven't found an answer you're happy with, let me suggest the Toshiba PDR-M4. Even works well in very low light.

If you've found a good solution, please ignore this. If you haven't, feel free to contact me and I'll tell you all about it.

-mark grebner Mark@Grebner.com

-- Mark Grebner (Mark@Grebner.com), December 21, 1999.