How to pronounce Nikon's D5100?

Today I purchased a Nikon D5100.

I know that it's an upgrade on the D5000 which I pronounced D Five thousand. - but for the D5100 I pronounce it as D Fifty One Hundred, but my mate seems calls his D5100 a D Five Thousand One hundred…

Who is correct?

YOU are right! Your mate is WRONG.

I mean technically he is right too because that is just a different way of saying the same thing but fifty one hundred is how I have heard other people pronounce it as well.

In the world of photography, terms can be different than other instances of the language

For instance, in the scientific community, a Gigabyte is pronounce Jig-a-bite. Those in the world of computers and digital cameras, pronounce it gig-ə-byt

Not a big deal, but it can raise some eyebrows in certain situations

That means in the world of photography, you are correct.

Otherwise your mate is correct.