I've been rendering various images of some pill bottles and box packaging. When I render an image, say, of a box and bottle, I notice the image seems to be a little distorted. The is more noticeable if I render a shot of maybe 4 or five bottles lined up. The outside bottles aren't perfectly square. The top right corner seems off. I thought maybe it was because the "lens" was too wide angle, so I increased the focal length a lot and adjusted the shot accordingly, but the image still isn't perfectly square... still getting some distortion. What's the deal here? I would think vertical pixels would render vertical, without distortion. Am I missing something?