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09-14-2016, 06:01 AM - 4 Likes   #1
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LensRentals: Is Your Camera Really The Best Optical Test?

QuoteQuote:
One of the more common responses on various internet forums seems to be “this manufacturer or that needs to up their quality control.” There’s a bit of truth to that. A slightly less common response has been “your manufacturer, but not mine, can’t make their lenses without a lot of variation.” There’s a bit of truth there sometimes, but not very much. The broader truth is we’re observing an industry-wide issue. It’s not happening because lenses are worse. Lenses are actually better than they’ve ever been overall. There are some exceptions, of course.



09-14-2016, 06:54 AM   #2
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excellent article
09-14-2016, 06:55 AM   #3
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Yes, very good indeed. Should be "required reading" for all of us interested in lenses, and those who have experienced problems with them.

Thanks for posting
09-14-2016, 09:57 AM   #4
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I am pleased that he addressed the matter of "tilt" vs. "decentered". I am surprised, however, that he did not mention issues of mechanical tolerance in the body. Accurate alignment of sensor and mount flange is taken for granted, though there is no more reason to expect that then a perfectly aligned optical path in the lens.


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09-14-2016, 10:31 AM   #5
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There is another way to interpret the article. What Lensrentals has effectively done is to lower consumers' expectation and stop bugging manufacturers for the need to improve quality. While I don't doubt that some independent repair shops are inadequate, I honestly have a hard time accepting that reputable lens manufacturers are worse than Lensrentals. As someone working in automotive R&D sector, we have cutting edge design & testing equipment that independent shops have not even dreamed about and not the other way round. Often time, manufacturers do not want to tell outsiders their secrets; testing equipment and processes are often kept tightly controlled.

While I do care about my equipment and like to buy the "best" for a given amount of money, I also try to be reasonable and not yet chase after the latest and greatest. Lens quality alone does not guarantee good results. Having good technique and support (read tripod) are equally important. Lacking of these can turn the best lens into nothing more than a mediocre one.
09-14-2016, 10:56 AM   #6
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Very interesting. I enjoy reading Roger's little articles. Thank you very much for posting.

I guess it is fortunate that I am not using one of those really high resolution sensors but, since I certainly do not share Fred Miranda's ability, I probably wouldn't see the problems anyway.
09-14-2016, 01:50 PM   #7
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QuoteOriginally posted by Pixelhdr Quote
I honestly have a hard time accepting that reputable lens manufacturers are worse than Lensrentals.
Perhaps a comparable example here would be Tamron... It's not unknown, based on what I've read coupled with my own experiences, for K-mount Tamron lenses to come out of the factory with quite significant front-focusing issues (I've read about it on other brands of body also). I've had two 70-200 f/2.8 and one 28-75 f/2.8 with front-focusing that could not be adjusted out using my K-3 and K-3II's AF fine adjustment. Tamron's UK distributor and service partner, Intro2020, had my 28-75 for about a week and sent it back to me with that issue completely resolved. Now, I don't believe that Intro2020 is any more capable than Tamron, but the quality control at Tamron missed the fact that my lens was outside of reasonable tolerances...
09-14-2016, 05:04 PM   #8
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I see the issue here. The service department may be incapable or incompetent but the R&D certainly is more capable; that was what I was referring. Lensrentals suggested that they are even more capable than lens manufacturers R&D.

09-14-2016, 06:41 PM - 1 Like   #9
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This is also worth it for the link to one of his other pieces:


https://www.lensrentals.com/blog/2016/08/my-third-grader-analogy-for-lens-reviews-and-testing/


Love the dig at Ken Rockwell! :-D
09-14-2016, 07:52 PM   #10
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This may explain why Precision was incapable of resolving (no pun intended) the issue with my lens at infinity. If they are using a substandard method(s) of testing, it could have very well passed their internal test(s). In the end, Pentax resolved my issue by just replacing the lens entirely. New copy focused muuuuuch better at infinity, but now I wonder if they could tell the difference.

That is, would both a 'sharp' copy and a 'soft' copy potentially pass their test if the resolution of the testing equipment was below that of my camera's sensor? I get the feeling the answer is 'yes' from reading the lensrental article.

There were a couple other people I noticed with the same lens issue and the same outcome (Precision unable to repair) so it has me wondering now.. they might very well have decent technicians, just outdated testing equipment/methodology in place.
09-14-2016, 10:27 PM   #11
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QuoteOriginally posted by clackers Quote
Love the dig at Ken Rockwell! :-D
Tee! Hee!

(Another good article, BTW)


Steve
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