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Archive 2016 · Sony 70-200 GM - MTF Results Posted

  
 
GMPhotography
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p.2 #1 · p.2 #1 · Sony 70-200 GM - MTF Results Posted


RCicala wrote:
I will speculate a bit - and I have no inside knowledge regarding this lens. If I did, nondisclosures would prevent me from speculating. But the actual MTFs are way worse than Sony's computer projected MTFs. That always occurs to some degree but this is way different.

1) It's possible the test doesn't accurately reflect lens performance at infinity of the 10 early copies I tested. The only way I can figure this happens is that setting focus to infinity on the camera isn't accurate on this lens (it is on all other FE lenses), but I repeated them set
...Show more


Well Roger I'm renting it from you and my needs are 200mm about F4 not at infinity and in crop mode and only about 14 thousand images. Walk in the park.

I should be okay. Just tell the rental side send me a good one. Hey I'll even test a couple out if you want. Have a great Thanksgiving



Nov 24, 2016 at 12:05 PM
AtomicPunk
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p.2 #2 · p.2 #2 · Sony 70-200 GM - MTF Results Posted


After reading this, I canceled my almost 4 months old order for this lens. For almost the same price, I ordered the 70-200 f4 and the new alpha 6500.


Nov 24, 2016 at 12:09 PM
MJKoski
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p.2 #3 · p.2 #3 · Sony 70-200 GM - MTF Results Posted


Yes Joshua, we are Z class customers here. Currently many products cost more in euros than your price in dollars. For example Pentax K-1 situation is hilarious: Body + Pentax branded Tamron lenses costs more than Nikon D810 + Nikon equivalent lenses. Their strategy was supposed to be reverse of that.


Nov 24, 2016 at 12:51 PM
AGeoJO
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p.2 #4 · p.2 #4 · Sony 70-200 GM - MTF Results Posted


MJKoski wrote:
Yes Joshua, we are Z class customers here. Currently many products cost more in euros than your price in dollars. For example Pentax K-1 situation is hilarious: Body + Pentax branded Tamron lenses costs more than Nikon D810 + Nikon equivalent lenses. Their strategy was supposed to be reverse of that.


I am sorry to hear that . Still, I believe that it has to do more with the currency exchange (and partly also, greed) and that a lot of international Japanese companies rely their profit and loss on US$. So, they tend to err on the cautious side if it is coming down to other currencies. So, if the euro remains strong, they will make more money and if they euro goes down, they are covered. The Euro is about to come back to a full circle after flying high for over a decade and a lot of experts anticipate it will be just around the corner in January 2017. We will see.



Nov 24, 2016 at 01:06 PM
MJKoski
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p.2 #5 · p.2 #5 · Sony 70-200 GM - MTF Results Posted


Ya, it is actually interesting. Many brick & mortar stores have sold out most of their used equipment which was not the case few years ago. People have stopped buying overpriced euro stuff and hunt for slightly used equipment.


Nov 24, 2016 at 01:16 PM
AGeoJO
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p.2 #6 · p.2 #6 · Sony 70-200 GM - MTF Results Posted


After some more thought I would like to add to what I posted previously - I have been using this lens for real-life photography and I am pleased with the results. However, it is still possible that my copy, being an early production, is not up to par. I am waiting until Sony comes up with either some kind of explanation or until they open the gate and more copies are available again after some tweaking and more tests have been done on those. Before I became a Sony Pro Imaging member, I had them replaced a sub-par lens within the warranty period. Now, that I am, I feel confident that they would do the same if indeed that the lens in general has undergone some kind of adjustment to get the peak performance. So, it is just a waiting game for me and in the meantime, I will continue using the lens normally.

Edited on Nov 24, 2016 at 01:33 PM · View previous versions



Nov 24, 2016 at 01:30 PM
Fred Miranda
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p.2 #7 · p.2 #7 · Sony 70-200 GM - MTF Results Posted


Definitely not good news for Sony if this is true.
Roger made it clear that more testing is needed for any final conclusion.

Perhaps the delay in production has to do with this issue and new batches will perform better. So, until Roger gets his hands on at least 10 freshly baked copies, we won't know for sure. Let's wait and see.




Roger's MTF at 70mm






Sony's computer generated MTF at 70mm




Nov 24, 2016 at 01:33 PM
DavidBM
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p.2 #8 · p.2 #8 · Sony 70-200 GM - MTF Results Posted


Fred Miranda wrote:
Definitely not good news for Sony if this is true.
Roger made it clear that more testing is needed for any final conclusion.

Perhaps the delay releasing this lens has to do with this issue and new batches will perform better. So, until Roger gets his hands on at least 10 freshly baked copies, we won't know for sure. Let's wait and see.


What's interesting and suggestive is that Rogers tests don't show the little bump of astigmatism in the middle to outer field that Sony's own mtfs do for 70mm wide open. So it's not just that his curves are worse; they are *different*. Which is some evidence that something funny is going on....



Nov 24, 2016 at 05:02 PM
Brandon Dube
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p.2 #9 · p.2 #9 · Sony 70-200 GM - MTF Results Posted


DavidBM wrote:
What's interesting and suggestive is that Rogers tests don't show the little bump of astigmatism in the middle to outer field that Sony's own mtfs do for 70mm wide open. So it's not just that his curves are worse; they are *different*. Which is some evidence that something funny is going on....


Not really. That local change is to do with aspheric surfaces in the lens (or, its size is). The MTF is very high, so the change in aberrations is not so great to produce that change in MTF. Roger's measured MTF is considerably lower, so the build aberrations absolute swamp the nominal ones in the edge of the FoV.

You can't call anything you see in an MTF chart astigmatism unless you know a lot about the measurement/computation either. It is more likely a change in coma.



Nov 24, 2016 at 05:39 PM
PEKA62
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p.2 #10 · p.2 #10 · Sony 70-200 GM - MTF Results Posted


Remember:
Roger's curves are *measured* ("this is what we see") whereas Sony's are *computed* ("this is how it should perform in theory")



Nov 24, 2016 at 05:41 PM
DavidBM
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p.2 #11 · p.2 #11 · Sony 70-200 GM - MTF Results Posted


Brandon Dube wrote:
Not really. That local change is to do with aspheric surfaces in the lens (or, its size is). The MTF is very high, so the change in aberrations is not so great to produce that change in MTF. Roger's measured MTF is considerably lower, so the build aberrations absolute swamp the nominal ones in the edge of the FoV.

You can't call anything you see in an MTF chart astigmatism unless you know a lot about the measurement/computation either. It is more likely a change in coma.


OK maybe not astigmatism then: but calculated difference between saggital vs. tangential mtf.

Sure the build aberrations might massively swamp the nominal ones. Or there could be issues to do with the accuracy of the set infinity focus, or something going on with the correction element.

My point just was the difference was very large in this case: larger than for most other Sony lenses, especially recent ones, and of a different shape as well. Maybe the manufacturing is just shocking on these, and that's what's going on. But it is suggestive of something systematic, and it's going to be really interesting to see how the next batch goes, and whether there are any issues bench testing this design. I have a completely open mind on this one (and am not in the market for a fast telezoon so have no irons in the fire!)




Nov 24, 2016 at 06:14 PM
DavidBM
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p.2 #12 · p.2 #12 · Sony 70-200 GM - MTF Results Posted


PEKA62 wrote:
Remember:
Roger's curves are *measured* ("this is what we see") whereas Sony's are *computed* ("this is how it should perform in theory")


That's the point: this is an interestingly larger than usual difference between what we see (in specific conditions) and how it should perform in theory.



Nov 24, 2016 at 06:15 PM
snapsy
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p.2 #13 · p.2 #13 · Sony 70-200 GM - MTF Results Posted


If I remember correctly Roger's test bench measures at infinity focus. Are Sony's calculated MTFs at infinity as well?


Nov 24, 2016 at 06:55 PM
Moroni
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p.2 #14 · p.2 #14 · Sony 70-200 GM - MTF Results Posted


Roger is going to be posting some real world comparisons soon, using an adapter. Can't wait for the results.


Nov 26, 2016 at 03:36 PM
Lucinda
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p.2 #15 · p.2 #15 · Sony 70-200 GM - MTF Results Posted


I love the 70-200mm GM f/2.8, I usually shoot at f/2.8, I got one the week it was released, this lens is amongst the finest I have used, it has that pop, look and contrast that I love to see.


Nov 27, 2016 at 02:34 AM
uhoh7
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p.2 #16 · p.2 #16 · Sony 70-200 GM - MTF Results Posted


The huge gap in Sony Charts and Rogers, combined with the technical issues, and the great shots from Joshua, make me wonder........

In a case like this, I would try to get some real world comparisons with each lens on it's own body and MP close as feasible. D810/A7r2/5D4 or sr.

Tripods, long landscape or cityscape, F/2.8, that would be much more definitive considering technical issues on the bench, or so it sounds to me in this case.

Even just a straight shoot out on A7r2 with Canikon adapted would be informative. If Roger's test is right they might well be noticeably better on the Sony body--let alone the Kolari r2

Where can we see some typical gaps between projected charts and real world bench for other lenses?




Nov 27, 2016 at 02:57 AM
Lucinda
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p.2 #17 · p.2 #17 · Sony 70-200 GM - MTF Results Posted


a few.

















Nov 30, 2016 at 04:53 AM
Schlotkins
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p.2 #18 · p.2 #18 · Sony 70-200 GM - MTF Results Posted


Infinity versus close up?

https://www.dxomark.com/Reviews/Sony-FE-70-200mm-f-2.8-GM-OSS-lens-review




Jan 24, 2017 at 01:45 PM
AGeoJO
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p.2 #19 · p.2 #19 · Sony 70-200 GM - MTF Results Posted


Schlotkins wrote:
Infinity versus close up?

https://www.dxomark.com/Reviews/Sony-FE-70-200mm-f-2.8-GM-OSS-lens-review



How about neither but just real life working distances ? I prefer taking my images that way anyway.



Jan 24, 2017 at 02:59 PM
chiron
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p.2 #20 · p.2 #20 · Sony 70-200 GM - MTF Results Posted


That is quite a review!


Jan 24, 2017 at 09:09 PM
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