Unwanted pixelated objects

I'm having a consistant problem where some of the 3D models in my scene are pixelated. This only seems to be happening when the scene is viewed through a camera; when I preview the draft on my computer there doesn't seem to be anything wrong. I briefly though it could be some glitch with the modeling process, as I have a mix of personal and downloaded models, but at least one of the ones I created doesn't pixelate. All of the downloaded ones are fine. Possibly relevant, I have some actions assigned which work in the preview but not through the camera. This affects both the pixelated and non-pixelated objects.