Nikon 70-200 f4

[Lance B]

I don't think it's a matter of my agreeing with your collective thoughts on TDP .. but what's pretty obvious when comparing TDP's actual images with other sites findings is that they're pretty much on par.

I can't understand how when a review site A seems to get similar results to review site B, review site A is not a trustworthy operator!
I'm afraid it's simply beyond my ability to see that as logical.

And it must also be remembered that not every site will get exactly the same results from the lenses they test compared with the test data from other sites, due to sample variation from each lens.
And while it's a populist approach to denigrate the likes of Sigma and Tamron

Populist to denegrate Sigma and Tamron? Really? The latest Sigma 35mm f1.4 has been shown to be a superb lens and outresolves the equivalent Nikon by quite a margin (a lens I have I might add) and the bokeh from the Sigma is also considered excellent and there is a flood of Nikon users showing outstanding results from it, and from what I have seen I agree, so you can't use that hoary old chestnut that "only propriety lenses get the accolades" excuse as that just isn't the case. When a top quality third party lens comes along, then it gets the deserved accolades.

among others for their higher levels of sample variance with their products, the issue is not strictly limited to these non primary manufacturer's!
Photozone, who I always keep a watchful eye on myself had an interesting review of the Nikon 70-200/2.8 VR(original version) .. where they tested multiple lenses of which a couple were good, or great and others which were .. quote .. "suffered from a rather pronounced centering defect".
On the original test for the 70-200VR, Markus only referred to testing two lenses, but in a subsequent post on another forum he went on to explain about 4 lenses being tested in total!

Can you link me to that info?

And this is a site that you do trust!

Well of course!! Because they took the time to make sure they obtained a good copy and ensure that the lens they tested reflected what could actually be expected of the lens. I don't find that strange at all.

I'm not entirely sure that a site should be trusted if take such liberties with one brand, but not extend the same testing procedure with others brands too!

How sure can we be that PZ's copy of the Sigma 70-200/2.8 didn't suffer from some unknown defect? Did they attempt to test another copy to be sure that it wasn't transport damaged, or something like that?

Sorry Arthur, but talk about paranoia. It's quite simple, the Sigma they tested didn't have the centring defects. They apply the same controls for the Sigma as they do all lenses and they have had to get better examples of other Sigma/Tamron/Canon lenses in othe lens tests due to decentring and other manufacturing irregularities. No need to think there is a conspiracy against Sigma or Tamron because it ain't.

Anyhow, as I already said, if you look at the data on TDP, it basically mirrors what PZ has found anyhow, with slight differences which can be explained via sample variation ... where the central resolution of the Sigma is approximately 93% of what the Nikon VRII lens is capable of .. and this is regarded as "doesn't come close in any department".
I'm not sure which dictionary this explanation comes from, but it's certainly not one that I ascribe too.(that one would be definitely deposited into a bin in my household)

In my book that isn't close when you look at other lenses tested and can easily be seen when viewing the difference in IQ. I have had both lenses of tests that have been tested on Photozone that show differences of less than 7% and that can be clearly seen. The Sigma 35mm f1.4 mentioned above will probably only have a resolution figure in the order of 5-10% more than the Nikon 35mm f1.4, similar to the difference you pointed out for the 70-200's, but to me that is a significant enough difference to plainly see. Again, it doesn't make the Nikon poor as it isn't, it is a superb lens, it's just not as good as the Sigma version and just like your Sigma 70-200 f2.8 isn't a bad lens, it's just not as good as the Nikon.

But of course the corners of the Sigma on PZ fail badly, as per their test.

Isn't this also part of my "isn't even close" comment?

But then they never spoke about decentering and testing another copy of that lens anywhere on that review page!
I have my theories on why this is.
(refer to my comment above about trust!)

Again, paranoia. Photozone has had to get decent copies of other brands lenses due to decentring and other irregularities. It's not a conspiracy.

Like I said, I trust only what I see and read, and make my conclusions based on what I believe is happening and subsequently referenced to other sites both known and unknown ... not what 'my mates and their mates' think this guy is doing and what his motives may be. I realise that there's an absolute glut of respected folks out there that known a few things about certain aspects of photography. And I'm not going to be one to argue with them about their ingrained ways .. they more than entitled to their opinions on their preferred sites!
My point is that I'm not closed to any site as a source of info, unless the info is obviously idiotic!!!
And one particular name springs to mind the moment i think of such as topic .... Kay .... Ahhhhh!
But even then despite all the lunacy of contradictory information on that site, it does have a few rare moment of normality and competence too(yep! hard to believe, but true)

Maybe so, but how do you know when to trust that particular site?

I can't see any reason to distrust The Digital Picture's testing based on the images they present as data for each lens.
Apart from an anomaly or two here and there with the actual images, which is most likely due to variance between lenses, I see very similar IQ and patterns of IQ across the frame with the mutual lenses I have in my possession!
Of course my test target is much smaller than theirs are, and I use mine simply as a first step to determine what action I need to prepare for with any new lens .. but once that's done the chart I have never gets used again for months or years.

Anyhow, the (slightly off)topic has been bashed to a pulp from my end, and now there's a new kid on the block .. but my mind is almost now set(about which 70-200 I'll end up with in a few months), even tho I haven't yet sen enough proof to warrant my decision.

If you are shooting Nikon, then I think you will find that the 70-200 f4 will be hard to beat if you take price into consideration and the fact that VR seems to be up to 5 stops of handholdability. Quite remarkable. Added to that, it works brilliantly with TC's, better in this regard than the highly regarded 70-200 f2.8 VRII. If I didn't have the f2.8 version, I would be very swayed by the new 70-200 f4.