The video must normally be a full screen view of a cropped image of the full view. The only way a camera can change its field of view is by
1.) Changing lenses
2.) Using an optical zoom
3.) Digitally zoom (cropped image)
If it appears more wide angle "fish-eyed" now, it was cropped before and the programming or some feature selection has now changed. I doubt a backup camera would have a mechanical zoom lens!
I prefer the wide angle so this is good news for me.
The founder of JeepGarage.org, Scottina06, has a son Max who is in need of corrective surgery from an infection at birth that left one leg 4 inches short. We need to support our Jeep brothers. His family has started a fund on giveforward.com. If you have ever been helped by someone else, now is a good time to pay it forward. Here is a link to that page. God bless you! http://gfwd.at/1rz33PW