On Thu, 20 Nov 2008, Peter Alefounder wrote: > > Gordon Scott <[EMAIL PROTECTED]> wrote: > > > 2. At least 10 megapixels. > > > > It seems this is not necessarily a good thing. > > Maybe so... but that is what I want. Some old documents can be > quite hard to read, even the original item. What I want to achieve > is at least 300dpi for an A4 page, or a little larger (these > documents are not always convenient sizes), because I might have to > join several images together. I expect to have to re-size, rotate > and change perspective: for that, I find it is best to start with a > higher resolution than I want to finish with.
But if the quatlity is worse than, say, an 5Mpx camera, it's still not delivering what you _need_. This sounds like a time that you need to take a tough sample to a camera shop and try some real cameras. If you need 10Mpx for the resolution, that my push you to a digital SLR, together with a comensurate price. BTW I think my earlier CCD pixel size should have read nanometers not micrometers. Doh! > My thoughts exactly. No problem with a viewfinder for a distant > target, but close-up I would rather see exactly what is on the CDD > - particularly if the item needs to be done in sections. I've come > across manorial court rolls with some pages several feet long. How > do these cameras cope with things that are not flat? - not just > because they've been rolled up for centuries, but parchment that > wasn't flat to start with? Is there sufficient depth of focus? Depth of field should not be a problem given half-decent lighting. I've been known to use a cheap (about a tenner) halogen floodlight reflecting from foil or card to give a reasonably even and bright light. Flash from the camera often gives hotspots and glare on documents. You'll presumably be using wide-ish angle lenses, to depth of field should be huge. BTW, you'll need a colour balancing option or manual exposure control, as photographing white paper for example tends to fool auto exposures. > [3], earlier MJU series cameras all appeared as USB mass storage, > so I expect this one would do so as well. The three Olympus digitals we have/nad (one was stolen) have all appeared as mass storage devices, though are also recognised as a camera .. I guess that may also offer PC control, but I've never tried it. -- Gordon Scott http://www.gscott.co.uk Haiku: Tragic Irony Imagined Life Without Walls Windows Crash to Floor. Linux ... Because I like to *get* there today. -- Please post to: Hampshire@mailman.lug.org.uk Web Interface: https://mailman.lug.org.uk/mailman/listinfo/hampshire LUG URL: http://www.hantslug.org.uk --------------------------------------------------------------
