I thought people may find this a bit fun.
With my latest lens, I realized I had five different Nikon lenses that had 200mm as a capability.
The attached image (hopefully it will be visible full size), shows top to bottom five different lenses. The right hand images are (almost) at F4, with the faster lenses having more to the left in one stop intervals. The 18-200 was a 5.6 but I didn't want to bother shooting all the others at 5.6.
The most interesting one to me was a really old "Nikkor-Q Auto 1:4 f=200mm" lens, that I think is an AI conversion but do not really remember. I've never used it on digital as I don't care much for manual focus, but I was astounded that it looked as sharp as the 70-200, maybe as the 200-400. I cheated as bit as all the others were AF, that was live view focused (I also accidentally over-exposed and drew it down -1 stop in lightroom, so don't hold the more washed out label against it).
(Click for larger image)
Darn -- just realized, somewhere around here I have an old plastic 70-300 I could have done, but I hereby disqualify it as it doesn't have 200 as one specific end.
PS. Not scientific, bear in mind just for fun, and only one sample set, but to me the 200/F2 is the best, the 200-400 a close match at F4 (I think the 200 is better but I'd be hard pressed to pick it out unlabeled), the 70-200 runs about 1 stop behind each in sharpness (e.g. at F2.8 it looks about like the 200 @ F2). The old 200 is surprisingly good, maybe up to the 200-400 and I think better than the 70-200, and the 18-200 just shouldn't have even been in the running (that image is to scale -- it wasn't even a real 200).
PPS. The snippits are 2:1 screen shot cuts from LR. With Nikonians gallery processing not exactly sure how they show, I think it then shrunk it down. They are approximately 320x270 pixels.
Comments welcomed on pictures: Http://captivephotons.com