Make DVD image in Mac OS X without third-party tools?

Is there any way in Mac OS X 10.5.x to create a .dmg image from existing physical DVD, without a third-party tools installation? I have carefully examined "disk utility" and searched Google, but it seems that all people just write .dmg files, no information on how to create them from physical DVD disks.

1. Launch Disk Utility
2. Select the icon for the CD/DVD you want to image
3. Click the "New Image" button
4. Choose "DVD/CD Master" as the image format, this creates a CDR image (an ISO basically) which is the only block-level image format available in the Disk Utility GUI (and also the only format you can easily mount in Windows should you want to)
5. Save

Have you tried dd?

You can create an iso of the DVD in the following manner.

*Open a new terminal*
mount <look for the entry that says /dev/sdX DVD/CD ROM>
dd if=/dev/sdX of=dvdimage.iso

This should be what you want.