Research: What sub-genre will my film be?

Having had a look at the different sci-fi films which branch out into a wide variety of different sub-genres, I have come to the decision that I will be making a short film which will come under the theme, post-apocalyptic/apocalyptic future. For several logical reasons I chose this. For one, I do not have the technology to create CGI characters or to implement highly realistic special effects into my work. Secondly, I do not have the budget to develop my film into something that creates new landscapes which take the audience to different worlds in space and time. Thirdly, I do not have the budget to afford costumes that are built to withstand force and to look professional and exciting.Therefore, with going for an apocalyptic future I do not have to use special effects or CGI characters to make it look realistic and therefore I can retain it's value as being a film, part of the sci-fi genre.