You imply I said something incorrect, but what specifically?
You said "mainly for architecture use". That lens was never marketed as such—you can find archives of all of Canon's material from then—and architectural photography at the time was dominated by large format, though even on 35mm there were at that point shift lenses which were being offered for this task. The pancake (mirror lock-up) 19mm was very specifically advertised and sold for street photography.
I never said it was good optically,
If someone says "I'm not sure this lens will have good optics" and you reply with "well there was this other lens before that did alright", you're very clearly trying to say there is little, if not no, reason to doubt the optics of the new lens.
Don't bring up something as a conversation point if you're going to fall back on "well I don't know, it was a long time ago, it's not really my thing". If you're that unsure about something then don't try to put it forward as a talking point, let alone as a potential example to reassure (or dissuade) someone about a new product.
And for the record, yes, you are right that the 19mm wasn't quite literally 19mm; it was 18.7mm. Really struck upon the weakspot there, good job.
Has anyone seen any early image quality reviews yet for the 16mm? I thought some reviewers might have had a copy to test and just had to wait until the official announcement to publish, but I haven’t seen any optical test results yet.
1) It's only been in peoples' hands for a couple of days, far too early for any actual "reviews" of it.
2) Most of the media are just focusing on the R3; apparently there are very few actual working units of the 100-400 and 16mm to hand out. (And they don't draw clicks like a new body does.)
3) The few people who have gotten to play with the 16mm have only been allowed to report on the in-camera processing from the back of the camera. Nobody has been allowed to keep files. I've already seen one store proudly proclaim the lens has no distortion, only to then admit they forgot to check if the camera was correcting that automatically and that they hadn't looked at even the jpgs, let alone raws. Literally, everyone who has touched the 100-400 and 16 have only seen the images on the rear screen of the camera.
Canon have gotten stricter with their embargoes lately and nobody who has touched the R3, 100-400 or 16mm yet can really say anything about any of them other than repeating Canon's marketing. It's going to be late October before anyone who can actually talk freely about them will be able to get hold of one and use it for long enough to have some meaningful results.