For the record, I checked my renders and neither had DoF enabled. What you see is the image on the EZDome.

Again, both renders I posted above, without DoF were the exact same height and width, both were set to render 300 DPI. Poser 11 rendered it as such, while Poser 12 rendered as 72 DPI. Poser 11 test scene rendered JPG size is 721 kB, Poser 12 scene size rendered JPG size is 631 KB.

While this discussion has been immensely educational for me (and probably many others) regarding Photoshop and image sizes in general, the fact remains: Poser 12 renders images in 72 dpi regardless of size or what you tell the program. It is a bug, and has been reported as such by me and probably many others. As of today, there is no fix, except rendering your image out in huuuuge size even for smaller output.