http://ricehigh.blogspot.com/2010/03/fa-31-limited-assembled-in-vietnam-vs.html
As for Ned's blog post and his posted comparison photos mentioned, I actually made a guess at his post but unfortunately my that simple guess for which is which has never appeared on the net. It is because my that comment has been censored and blocked by Ned. :-(
[ Update (4-6): Ned has released my that posted comment today, 8 days after my submission and coincidently a few hours shortly after my this post. As I could see that Ned has been active during these 8 days at his blog, I am still not convinced that why it has been taken so long for such a simple and short comment (of mine) to get it "approved" and posted.
Still, Ned hasn't revealed his answer, on which is which. :-( ]
I am a bit surprised for that happening (but not totally surprised at all as I think he might have a sole intention to "protect" the interest of Pentax for trying to hide something that can be very true) but I supposed Ned should be prepared (actually he should be well prepared!) for people started guessing which is which for what he posted and once he posted something like that. But however, since my that simple comment for the guess has been blocked, it is quite obvious that he simply don't want people to guess as he only and just wants to tell us that there should be "no difference"!
But then I do see many differences in his "A" and "B" images in his post, I post his blog post link again:-
http://nedbunnell.blogspot.com/2010/02/country-of-origin-debate-over-lenses.html
And the direct links of his A and B pictures below:-
A: https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgdgZAt60Aah3w4LGG6gqd4PTzImHGPt5fQkk_pYVIvQD-LnOIdZAlC2vNex_SnktgJ3rTt8ChQynvOgMCLirxY7ezCvJWDRnc4yIB_RqWkX9K8MIyQyWaS9aJD8vEyeOg_pGN5gA/s1600-h/31mm+A.jpg
B: https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj7PkhRVmsmbemKvJbpz1IbXf3_ckRCNd51pvafT8-9zEg-HuiNeg9O1LJDaUTK8dUB2iJSOeVdpmZI-Cs-uNorMuiP_aDi5ArD0e3yAkaVtCXoG3AIOS11yifooAnsuDppnMwhyphenhypheng/s1600-h/31mm+B.jpg
I suppose you have downloaded the two pictures at this point. Now, do note that the differences in colour rendition, saturation, image transparency, focus accuracy, sharpness and contrast etc, although those might be not very obvious (but yet still noticeable, I believe)!
I guess "B" should be the image produced by the Japanese lens (but of late Japanese production, I believe also), which was just what I submitted as a comment at Ned's article, which was censored and blocked anyway.
What do you think? Do you agree with me that there are various differences that you can see? Do you agree with me that "B" is the Japanese lens image? And, do you agree that Ned should block my that comment for just such a simple and quick guess? Do you think Ned should answer us which is which and also if my guess is correct?! (I don't mind my guess is wrong after all, but I do mind censorship and narrow-mindedness! :-o)
Well, next, as promised last time that I should show you folks that there exists material difference for the early Japanese Limiteds against the late Limited productions. So, I have taken two shots of the two different lens caps of mine that were produced at different times by Pentax. Do note the shots have just been taken at the same time and place, under the same lighting. I intentionally swapped the positions of the lens caps and took another shots to eliminate the possible positional effect due to the lighting that could be taken place (but that has been proven to be negligible). For even easier viewing, I put the two shots into an animated gif:-
Unlike Ned, I just don't put an "A" Versus "B" comparison here. And, the differences are actually just so obvious. Just in case if you are still unable to figure out any of these, I can still tell! Do note the fineness/coarseness of the metal texture and the colours and reflection of the metal, it is not too difficult to judge the material of the later Limited used is just inferior, isn't it? In fact, the metal of the old Limited looks more shiny and with purer silver colour too, whereas for the late production, the metal look dull and yellowish, and the texture is much coarser, too.
Last but not least, I have a truly humble advice to Ned: Don't try to hide the truth from the people, people will know, unless you just even don't know/notice yourself.. (Ned, if you read this, please don't take this as an offence, but just a humble advice of mine, truly.)
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When the Old is Unmatched by the New..