I know what the specs are, but here are 2 of my photos shot with the NIKKOR-AM 210mm lens which you can judge for yourself. 1st is an 8x10 self-portrait taken at f16, 1 second, Fuji NEOPAN 100 ACROS:
(Scanned on my EPSON V750; pardon the dust).
2nd photo is a 5x7 landscape taken at f22, <1 second, Fuji PROVIA 100F:
(drum scan courtesy of WEST COAST IMAGING). Hopefully, these images will upload properly.
Yesterday I exposed 2 sheets of 8x10 T-MAX 400 film using this lens for a portrait of my girlfriend and her 2 daughters. No vignetting on the ground glass. Give me a week or so to get the film developed and I will post it if you want additional proof :-) I can't explain it, I just know it worked for me. Weird, huh?