Is this a correct sentence?

"I don't trust todays cameras at all, excepting the Nikon D80, D90, and D300S."

Today's

Perhaps "I don't trust cameras today at all, except Nikon models D80, D90 and D300S."
Note: no comma after D90

I'm no English expert but this looks ok

"I don't trust today's cameras at all

Today's, except for.

Excepting is okay, but it's kind of old fashioned.

And, I have a D70.It's fine.

Most people don't say excepting. And yeah todays should have an apostrophe to show ownership. Here are some suggestions:
"Except for the Nikon D80, D90, and D300s, I don't trust today's cameras at all!"
"Out of all the cameras out there today, the Nikon D80, D90, and D300S are the only ones i trust."
"The only cameras i rely on are the Nikon D80, D90, and D300S."
ps: i'm glad to know i have a good camera.