Do movie theatre owners really prefer films made on 2k , 4k, and 5k cameras?

I heard somewhere that movie theatres prefer films made on 2k cameras and above but those are expensive, hard to come by, and knowledge of using them is another issue in itself. I wonder how other indy filmmakers do it. I would like to make a movie myself and send it to film festival but I do not have the means of getting my hands on a 2k like the Arri Flex now in my life. Is this a really big issue? I own the Canon 5d mark ii and the T2i for dslr filmmaking and I love them because they are small. Any input would be great.