Create an iso...
...is there a similar application that will take a dvd and make i into an .iso?
If (a big if) all you want is to create an iso from a DVD, then do this:
1. In Disk utility create a disk image (.dmg) from the DVD you want to copy/backup/whatever. Disk utility is in the Utilities folder, inside your applications folder.
2. Open the terminal and type this:
iutil convert /path/to/filename.dmg -format UDTO -o /path/to/savefile.iso
Replace
/path/to/filename.dmg with the path and name of the existing .DMG file, and replace
/path/to/savefile.iso with the desired path and name for the converted image.
IF all you want to do is back it up, then just create the dmg file, so you can burn it later, and DO NOT do step 2.
IF you want to convert it to another format to save space on your hard disk, rip it with Handbrake
IF you want to play it on your computer without the physical disk, rip it with MacTheRipper
IF you want to rip a bigger than 4.7 GB disk and fit it on a 4.7 GB disk, rip it with MacTheRipper, then use DVD2OneX to "shrink" it to fit on a single layer DVD.
That should do it, only on the last scenario you should need to buy any software (DVD2OneX).
Hope this helps.