Setting up two separate blogs while using WordPress as a CMS

If you want the two to be completely separate (as you hint at in your question), you have two (or three?) options:

  1. You install multiple blogs with a sub-directory structure of your choice. This way you will have complete control of your URLs. For example you could have one install running out of your /blog directory, and have another one running out of /blog/photography/blog. Make sure you read this article for more info.

  2. You run a MultiSite install. It will be a little trickier to setup, and you would probably need to write some URL rewrite rules to achieve what you want to achieve, but the pro of this approach is that you’ll manage both sites from one admin panel. Check out this guide for guidance.

  3. This being said, if you don’t want such separation you can always play with category names and URL rewrites to make it happen as well. I’m just not sure how separate you want the two to be.