Lotusm50
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I was trying to stay out of this. I've voiced my opinion on this enough times in the past. But I really feel I should address the logic of the statement below. While seemingly sounding reasonable, it really is in my opinion, misguided.
"Many testers out there trying to do their best" is useless if they all are doing it wrongly, or inappropriately, or inaccurately. Many people doing it badly, no matter how well intentioned merely further confuses and obfuscates truth and reality, and is worse that just one person doing it badly. Further, these "testers" don't preface their testing and analysis by saying they are "trying new test methods". They present this stuff as Gospel, as the highest scientific fact, and how they are revealing a hidden truth that others don't see and manufacturers actively conceal.
Some of these sites don't even mention what their test methods are, other secrete it deeply in their sites so you really have to look for it, others still describe it incompletely so you don't get the full picture. But beyond all this, most of their readers know even less than the testers. So how are they going to effectively assess methodology, even if they can find it? When someone who has knowledge, experience and insight calls these testers on the flaws in their approach, they vociferously fight back defending their "integrity" and self-anointed roles as "experts". Dare I say that Carl Zeiss knows a lot more about lens testing and measurement that the PZ boys? The PZ boys it would seem, might just give me an argument.
What I don't know if whether these testers 1) don't really know better (ignorance), 2) know what might be a better approach, but don't have the equipment, capital, time, etc. to do it properly, or 3) are completely cynical - know they are doing it poorly, but it can be done cheaply and they can sell it. I'm not sure which is worse.
If many people are doing it badly, and one is doing it right, what does that look like to the consumers who don't fully understand optical science? Majorities can be wrong. Many people coming to the similar conclusions using variations of similar flawed methods doesn't make it right.
I also reject the cynical statement that manufacturer MTF's "reflect the strongest performance of the lens". Manufacturers measure each of their lenses the same way. In particular, they are all measured (or calculated) at infinity even if the lens is optimized for a different focus distance. Special purpose lenses deviate from this, to address their special purpose -- Macro lenses are given additional measurements at close-focus distances, and tilt/shift lenses are often tested to a larger image circle (becuase they create and use a larger image circle -- even if this shows the weakest area of performance). Each manufacturer may use a somewhat different methodology to create their published MTF's, but each manufacturer measures all their lenses with pretty much the same methodology regardless how it might present a given lenses. If you actually examine these manufacturers' MTF's charts they often do show the lens' weak points. But, of course, you have to know what you are looking it. Certainly some corporate cynicism is warranted, but this is not really the most appropriate area to express it.
No, I am not happy, and we should not be happy, that so many rank amateurs and charlatans are out their presenting themselves as experts and flooding the marketplace with bad and/or misleading information. One spouting nonsense can be easily ignored. But many, propagated by the Internet, is creating a pandemic of misinformation.
scalesusa wrote:
There are many testers out there trying to do their best, and trying new test methods. I respect them all, but I also have my own opinion as to who does the best job(its my opinion, so I'll keep it to myself, but its not DXO).
Normally though, after you read the test method, camera used, and dig thru the data, the data pretty much agrees, even if the artifical rating they assign seems to favor different paramaters.
So, let the actual data do the talking, read it, understand it, and compare it and a pattern will emerge as to which is best for you.
I think we should be happy that we have many testers testing lenses and to let us know how they rate them.
As to lens manufacturer's MTF charts, consider that they are not stupid, the charts reflect the strongest performance of the lens, they are not about to show the weak points, I wouldn't either. They are completely accurate, as far as they go....Show more →
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I did my first post in the alt forum before you 
