Hi, Sat 05 Jan 2008 16:45, Vincent BAIN wrote: > If you follow Markus' how-to, you may be interested in technical info > concerning your camera : > > Kodak DCS Pro SLR/n/c > imager size : 36.0mm x 24.0mm > pixel size : 7.9µm x 7.9µm
exactly. even if you (for unknown reasons) do not follow Markus' how-to, you will need this information. and it won't hurt double-checking the correctness of this data against, the DPI in the EXIF data. given that, it's pretty straight-forward to set-up precise fiducial marks. (cf. http://edclxs22.cr.usgs.gov/osl/figure2.gif && http://grass.itc.it/grass63/manuals/html63_user/photo.camera.html ) *but* what is tricky is getting the calibrated focal length right. (and this of course (distortions!) is a quite important parameter) > Le samedi 05 janvier 2008 à 23:25 +0800, Maning Sambale a écrit : > > Camera: Kodak Pro DCS 14N digital SLR camera > > using a 19-35mm Tamron zoom lens set at 19mm focal length ok, his info is not so shabby, at least you know the "calibrated focal length" should be ~19mm. also the spec of the lens should include the focal length tolerance. (aka by how many percent the calibrated focal length is off from the value of 19mm.) cf. http://grass.itc.it/grass63/manuals/html63_user/photo.camera.html && and thread "[CREATE] Lens correction database" @ http://lists.freedesktop.org/archives/create/2007-May/thread.html#743 > > SHUTTER FOCAL LENGTH ?? not quite sure. are these actually to different paramenters, namely the shutter speed && the focal lenght? or what is this?? cheers, s. ps: if anyone knows a good trick to do a precise focal length calibration, plz don't keep it as your secret, but share it with us :)) SCNR. _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
