On 05/11/2014, Tom Fine wrote:
>> I do use a digital camera for photographing album covers, and large
>> posters, etc but I admit that I take pictures outside on cloudy days.
>> No artificial light or refection issues that way.
> Hi Paul:
> What do you do to avoid perspective distortion (non-squareness)? It
> seems like, for a poster, you'd have to have the camera up so high
> that there would be some shadowing or reflection in a poster with any
> gloss to it.
Put a small spirit level on the camera to make sure it is square on the
For big originals it is safe to use a moderately wide angle lens. Not
too wide and vignetting, distortion etc begin to be problems.
Zoom lenses are only OK if of very good quality -- not the standard
"kit" lenses that come with the camera.
A polarising filter will help with reflections on glossy originals.
The best results I have had from a camera is from a Sigma DP3M. This is
a rather unorthodox model with extremely high resolution. There vis also
a DP2M with a wider angle lens. Both models are more or less
discontinued, and they have recently been available at low prices.
Click on the image to see it bigger, with option to View Original.
> I would like to know more about this method because I have some
> large-scale schematics I'd love to digitize in some other way than
> trying to tile together 12x18 segments.
> My wife had suggested something similar to what I think you are
> saying, using a tripod and spreading the document out on our deck,
> holding the corners down with weights. The problem is, no matter where
> I put the tripod, there was perspective distortion because the lens
> wasn't centered over the center of the document. That is the main
> advantage for a photo stand, centering the camera over the image.
> I wonder if it's possible to rig up a mechanism whereby a digital
> camera "flies" over large documents like posters or schematics and
> uses built-in panorama software to stitch the segments together? The
> segments should stitch easily due to rigging a mechanism where the
> camera is kept at a static height and static vertical angle to the
> document, moving on a controlled horizontal path.
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