Was distortion that big of an issue on the old photos? What would cause the distortion? I'm assuming that this is not an issue with modern cameras
Nearly all lenses produce some sort of distortion, and it is indeed an issue with all cameras, old and new. Cheap lenses usually, but not always, have more distortion than dear ones of similar focal length. The most obvious distortion is caused by wide-angle lenses, which were used on the lunar surface cameras.
Last weekend I browsed through a few hundred Apollo 16 photos on my hard drive and there was one taken of the rover, looking along it from one end. The pair of wheels nearest the camera looked much fatter and much wider apart than the pair on the other end, but the rover wheels were all the same width and both pairs were the same distance apart.
Not sure if it was this photo, but the effect is there:--
http://www.hq.nasa.gov/alsj/a16/AS16-114-18454HR.jpgYesterday I saw a photo in a real estate advertisement which was taken inside a bedroom. The top of the high wooden foot of the bed was nearest the camera and would have been horizontal in real life, but it had a very noticeable lean of about eight degrees to one side. Not that every viewer would have noticed at a casual glance -- I was a professional photographer back in the 70s and 80s and am still an amateur.
If you have the experience and know what to look for, you'll see distortion in many photos, but some of what gets called distortion isn't actually -- it's more a case of our brain making corrections so that we "see" things like converging lines as straight, but in truth they actually curve.
This effect is most noticeable in Moon Illusion No. 2, in daytime when the moon is at first- or last-quarter and both sun and moon are visible. The straight edge of the shadow on the moon is not perpendicular to a straight line drawn to the sun. It has a noticeable lean. But in reality that line would curve to the sun, so everything is, in fact, in order.
Google "moon illusion" if you want to know what No. 1 is -- it's about our perceptions and assumptions, which can be wrong. Moon Illusion No. 2 is harder to find because far fewer people ever see it and question it, yet it occurs twice as often as No. 1.