I was finally able to get my Sony Vaio SZ730's motion eye to work
(usb id code 05ca:183a as seen by lsusb ) which is probably very similar to your 05ca:1839
by using this:
package which you download as a compressed tar file, mine was called
r5u87x-f40ecd392efb.tar.bz2 I'm guessing the jibberish name after the "-" is from an
svn tag or something so the name might change when you get it.
(note the 1839 is in the docs/model_matrix.txt file in the package)
What I liked about this project is I finally found one with recent activity, the other Ricoh drivers I found were years old. The last code update was nine days back.
download the package from the download link at the upper right, untarring it
and following the instructions in the README. One tip, the first time you load it after
doing the make, make install, it won't seem to work. Like the README says, I needed to do:
after the reload it was working (by viewing the image in camstream).
Note to get the compile to work, you'll likely need to install package
libusb-devel, r5u87x needs it as mentioned in the README but my Fedora 10 copy didn't have it by default.