I recently bought a used Cannon EOS Digital Rebel XTI 400D. I went on a trip and took some photos that I would like to get onto my mac (A mac mini running 10.6.8). When I plugged the camera into my mac iPhoto started but the computer did not show the camera in iPhoto or in Finder. I looked for drivers to download but could not find any. For the moment I am using a pc to get them off the camera for the moment, and transferring them with a flash drive but I would like to be able to not have to use such a roundabout process.
You need to install Canon's EOS Utility in order to download the pictures directly from the camera. Canon DSLR cameras do not appear as generic logical drives like some other manufacturers' DSLRs. EOS Utility is included on the disc that came with the camera. Updates are downloadable at Canon's website (under the software tab, rather than the drivers tab), but normally either a previous version needs to be installed or the disc present in the optical drive for the download to install. It appears the last version of EOS Utility that officially supported the Rebel XTi was version 2.9.0. The last Mac OS this version was officially listed on the Canon support page as compatible with was OS X, but the user manual lists OS X 10.2-10.4. This may or may not work on your OS X 10.6.8 machine.
If you search for EOS utility via the EOS Rebel XSi page, there is a listing for a version of the EOS Digital Solution Disk Software 28.2A for Mac OS X (For users who cannot use the bundled CD). The included version of EOS Utility (ver. 2.13.20) may or may not support the XTi.
You should not need the EOS Utility to connect your Canon to the Mac.
Three things to check:
1) EDITED PER BELOW: The Canon 350D (Xt) had a setting on the Setup2 menu that chose PC CONNECT vs PRINT/PTP. If the camera is set in PRINT/PTP, it will not connect to the computer correctly. This is not the case with the Canon 400 (XTi).
2) Check your usb cable
3) On the Mac, you need to instruct OSX what to do when the camera is connected. The fact that the camera does not show in Finder suggests either 1 or 2 above is the culprit. However, OSX can act funny when you have don't have Image Capture configured correctly. In Spotlight, (hit apple+space bar) type 'Image Capture', and hit enter when you see the Application listed. Your camera should be listed if it is connecting properly. Here you can define what default actions you wish to happen when you connect your camera...for example, you can have iPhoto launch and import begin.
4) If you have a VMware or Parallels running, often these will capture the USB port, assigning it to the OS you have running in the VM. The Mac OSX side will behave as if the camera or printer is no connected.