RF 600mm f/4 L IS USM

So looking at your tests, it's bizarre that the EF 2x III is better, but Bryan's crops show the RF 2X having a clear advantage.

My only explanation is the RF extender is optimized for the RF 600mm. Which if I am correct is optically the same as the III. And since you were testing it on the EF 600mm f/4 II. Maybe that is the reason for the discrepancy between your results and Bryan's results.

But even then it hardly makes a lot of sense since the 600mm II is actually a touch sharper than the 600mm III.

There possibly could be some sample variation in the mix as well.

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Originally Posted by Fast Glass

But even then it hardly makes a lot of sense since the 600mm II is actually a touch sharper than the 600mm III.

There possibly could be some sample variation in the mix as well.

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Copy variation?


I ordered the RF 1.4 and RF 2x extenders last night.
Also ordered LensCoat in RealTree, wasn't able to get the Hoodie though.
Went with the Lowepro Lens Trekker 600 AW III, I would have went with the Tamrac version but apparently they do not make their Expedition 9 anymore and the version they had for big lenses were not in stock.
I am set.

@HD

Yup, copy variation. Sample variation. We talking about the same thing.

That's awesome, I would definitely say you are set!

Gonna do some testing with the 1Dx III, R5, possibly R3, 200mm f/2.0, 300mm f/2.8 IS II, 300mm f/2.8 IS, 70-200mm f/2.8 IS II. And all my existing bodies, 1DS III, 1D III and my old 60D, just for kicks.

I want to see which is the right body for me. And most importantly which one has the best AF. I have some of Canon's best auto focusing lenses and gonna give them a through run down with an 35 year experienced, and very good friend, photographer. I never seen a really good vid comparing the 1Dx III and a R3 or even R5. So I want to put them through their paces, and see which one has the best AF. I suspect the R3 will be a fantastic all arounder. But will it, or can it, out pace the AF of the 1Dx III. That I want to find out.

And I think I might do a video on my findings and get something like the Atamos screen recorder. So I can get some in view finder footage as well. Along with sifting through all the images.

Fun times playing with 25k worth of gear!!!!!

Copy variation definitely occurs, it’s more common in consumer lenses than L series lenses, but certainly occurs in the latter. For example, check out Bryan’s review of the EF 24-70/2.8L II. He ended up testing four copies of that lens because the first two did not perform well. When I was reviewing the EF-M 18-150 for TDP, my results differed substantially from Bryan‘s posted ISO 12233 chart images. He ordered another copy and tested it, found it was significantly better, and replaced those images in the tool.

I did test my RF 1.4x and 2x with the RF 100-500, and the results were as expected, so I don’t think there’s an issue with my RF 2x. In real world shooting, I’m not sure those differences would be evident anyway. But I do definitely recommend testing a new lens when you get it.

Indeed. I have seen sample variation in lenses I have owned as well.

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Originally Posted by neuroanatomist

Copy variation definitely occurs, it’s more common in consumer lenses than L series lenses, but certainly occurs in the latter. For example, check out Bryan’s review of the EF 24-70/2.8L II. He ended up testing four copies of that lens because the first two did not perform well. When I was reviewing the EF-M 18-150 for TDP, my results differed substantially from Bryan‘s posted ISO 12233 chart images. He ordered another copy and tested it, found it was significantly better, and replaced those images in the tool.

I did test my RF 1.4x and 2x with the RF 100-500, and the results were as expected, so I don’t think there’s an issue with my RF 2x. In real world shooting, I’m not sure those differences would be evident anyway. But I do definitely recommend testing a new lens when you get it.

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I went through multiple copies of the EF 24-70 f2.8 II before I found a pristine one. Big primes I think are held to higher level of Quality Control.

The discussion about the RF 2x I think started with Brant.
It wasn't a problem with the RF 2x, it appears to perform better than the EF 600mm III version with a 2x.

https://www.the-digital-picture.com/...mp=2&APIComp=2

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Originally Posted by HDNitehawk

It wasn't a problem with the RF 2x, it appears to perform better than the EF 600mm III version with a 2x.

https://www.the-digital-picture.com/...mp=2&APIComp=2

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The difference is that Bryan's comparison is using different cameras with (slightly) different resolutions and different OLPFs (the 5DsR has a 'self-canceling' AA filter, the R5 has an AA filter (not sure if it's the newer design used on the 1D X III that has four layers instead of two), and Canon's DPP sharpens up AA filtered images very well.

When I compared the EF 2xIII with the RF 2x, I found the former to be sharper when using the same lens on the same R3 camera, with identical processing – pretty much the most apples-to-apples comparison possible, for the given sensor resolution (which is significantly lower than the 45-50 MP of the 5DsR/R5).

Quote:

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Originally Posted by neuroanatomist

The difference is that Bryan's comparison is using different cameras with (slightly) different resolutions and different OLPFs (the 5DsR has a 'self-canceling' AA filter, the R5 has an AA filter (not sure if it's the newer design used on the 1D X III that has four layers instead of two), and Canon's DPP sharpens up AA filtered images very well.

When I compared the EF 2xIII with the RF 2x, I found the former to be sharper when using the same lens on the same R3 camera, with identical processing – pretty much the most apples-to-apples comparison possible, for the given sensor resolution (which is significantly lower than the 45-50 MP of the 5DsR/R5).

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Many variables at play. If I understand your testing you are using EF lenses.
It sounds like you have a fair comparison of an EF lens with both adapters.

The question I see raised, does the RF adapter play better with the RF lenses. I doubt it does, I think some of the EF 600mm III comparisons were because of a weak lens.

To your first point, if the EF 600mm III had been tested with a R5, and the RF 600 tested with a RF it might be a very comparable test.

Looking at Bryans test the EF 600mm II vs the RF 600mm with 2x the center is better on the EF and the Periphery on the RF.
https://www.the-digital-picture.com/...mp=2&APIComp=0
Then the difference between the RF 600mm and the EF 600mm II.
https://www.the-digital-picture.com/...mp=2&APIComp=0

Looking at all the charts it appears that there might be an issue with the EF 600mm III tested. If it is a soft lens the 2x would magnify the softness.

My RF extenders show up tomorrow, it might be interesting to see how the RF 600mm stacks up against the EF 500mm II at the same and equal framing distances.

My testing was with just one lens, the EF 600/4L IS II. I was going to write that I've offloaded all my EF lenses that take a TC so that is my only option, but upon reflection while that would be technically true since TS-E lenses aren't EF, I could actually repeat the test of EF vs RF extenders alone and combined with my TS-E 24L II, a wickedly sharp lens.

Could be that Bryan got a suboptimal copy of the 600 III.

Will be interesting to see what you learn!

I just looked at the teleconverters and they appeared to be the same optical formula just with a modified external caller that adjust for flange distance