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Thread: RF Native Lens Cropped vs 1.4x vs 2x

  1. #1
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    RF Native Lens Cropped vs 1.4x vs 2x

    After I finished testing my lens, it occurred to me the method I used would probably give me a comparison from cropping to using an extender.
    I had set the test up at the same distance (real world you would be using the extender or cropping from the same distance). Shutter speed remained constant at 1/500, all the shots are wide open and the ISO is set to Auto. This means that each shot has a higher ISO, with the exception of the 2x which I supplemented the light because it had become unusable. The 2x has a lower ISO than the native lens. The samples are cuts of screen shots hand scaled and zoomed in to be the exact same size (the exception is the Native shots which wouldn't scale precisely but were close), where I am now I didn't have editing software. All shots are with the R5. YMMV if you are using a lower MP body.

    In the center what I am seeing is a benefit to use the 1.4x in the center. The Native crop is slightly better than the 2x, compound that with the loss of light due to the higher aperture I give the Native the edge. The 1.4x Crop is straight up better than the 2x. My opinion is that for any long work you would use the 1.4x and crop rather than use the 2x.



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    For the Corners the 2x is weak. The Native might have a little edge over the 1.4x cropped, and it might not. It is debatable.

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    At this point I see no reason to own the 2x. I can get the same results by cropping and not lose the light. For distance the 1.4x is the way to go.

    As for the new lenses released, I think you would get fair results out of the 800mm but you loose light which is a big negative. The 1200mm MTF's show the lens as sharp as the 600mm with the 2x in the center. If that is the case the 1200mm is going to be a semi soft lens and for my use very limited applications.

    Neuro did a comparison of the 1.4x and 2x EF versions vs the RF versions. It is a good read. Hope he doesn't mind, but here is his link:
    https://www.canonrumors.com/forum/th...l-is-ii.41215/

  2. #2
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    I wasn't able to get the 2x Corner and Native Corner comparisons in the last post.
    Here they are.

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  3. #3
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    Here is the same test on the 500mm. It was shot at 20' from target where the 600mm was shot 24'.
    The 1.4x is excluded because of the bad results, something isn't right with the extender.
    The Native was better in the center. I give the 2x the edge in the corners.
    It should be noted the 2x had a very high ISO.
    My opinion is that if you have a select purpose to use the 2x and have time to arrange it it could be used. But on the fly you could crop and accive close to the same results.

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  4. #4
    Senior Member Fast Glass's Avatar
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    Well something you have to consider is the affect of overall IQ or how far you subject is.

    If you are very far away, you have to have some kind of resolution on target you'd have to have the 2x on and crop from there. Crop too heavy and it will look that way.

    You also can't escape the increase in noise which is proportional to bumping up ISO with crop. You are not gaining light by not usingan extender. You increase perceived noise at the same output size with cropping just as much as using the extender and bumping it up. Used to be in the old'en days when using the 1Ds III as your body of choice. You had a native ISO 1600, expanded 3200. So it wasn't always a simple matter of just bumping up the ISO or pushing it past in post. So sometimes cropping was the solution. Sensor tech was not there yet.

    Today with say the 1Dx III, it handles noise like a boss and a native ISO of 100,000!!!!!!

    I'm just tossing in more variables in the mix and more scenarios why you might want to use the 2X. I would suspect you only have so much room to crop that regardless of the softness just having enough sensor and resolution on target will be more important.

    Also, If you make another test like this. Maybe do it outside so you are able to use ISO 100 on all your shots and not inducing detail killing noise. Also with the exposures being so dim and white balance off. It kinda plays tricks with my eyes and makes it more difficult to judge them. I can still tell what is sharper. But them being the same exposure and WB would be nice.

    Also, did you manually focus these results? I would not trust the AF for critical results. Because some look like they may have been miss focused by a significant amount. It looks much more than softness on at least one of them. The 2X results.

    Just my 2 cents anyway.
    Last edited by Fast Glass; 03-03-2022 at 06:27 PM.

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    Yes manual focus, IS off, on my heavy duty Gitzo tripod and Wimberly head. Set the 10 second timer because you could see vibration from your hand when touching the camera.

    You could test multiple ways, truth is this is probably pretty close to what I would be doing in the real world. For instance it is a rare day I would be able to have an ISO of 100 at the prime shooting time. It is common in midday when your doing something like Road Hunting in Yellowstone. The higher ISO would come closer to showing a failure than if you had great light and ISO 100.

    I thought it was a fair comparison and here is why, a shot usually presents itself at a given location and distance at the exact same time. So a real life comparison would be the results you would get by cropping vs adding in the extender at the same distance in the exact same light. I could have decreased the ISO by going to a slower shutter speed, but in the real world I would seldom be under 1/500 and almost always shooting wide open.

    I found it curios that the RF 2x handled the higher ISO so poorly. The EF 2x did much better. I have thought / or at least felt for years that putting the EF 2x on was not that much different the cropping. This goes back to my first big white a dozen years ago.

    It might be overly critical to be shooting a target with a square that is .8 of an inch square and comparing it on a 32" monitor blown up to 8"x 8"

  6. #6
    Senior Member Fast Glass's Avatar
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    Lol, right!

    I do get the logic, and it is fair assumption. But sometimes trying to mimic real world scenarios don't make it easy to narrow in on a particular thing we are trying to test. In this case sharpness.

    To be fair, I wonder about the 2X extender results. Maybe sample variation or sometimes even 1/500 is not fast enough, maybe just a tiny bit OOF. I have been known to flub manual focus too once in a while.

    I just have a hard time accepting that the 2X is worse than cropping, lol. Because it would have to very soft to throw away all the sensor resolution and still come out on top. Not necessarily doubting your trials though. There could be other reasons for it.

    I'm trying to edit the samples you gave, but for some reason DPP won't edit the files. I can't do any general adjustments for some reason.

    I was gonna try my hand at getting all the white balances good, correct for all lens defects, use lens optimizer to apply CA and correct for lens abreactions/corner sharpness, any extremely minor noise reduction if necessary and sharpening to taste. As if it was a real photo. Just your basic run of the mill postprocessing.

    And see with real world post processing how it turns out. And much easier to see the sharpness difference without the WB shift and exposure difference.

    Actually it be nice to play with the RAW files altogether. LOL.
    Last edited by Fast Glass; 03-04-2022 at 08:28 AM.

  7. #7
    Super Moderator Kayaker72's Avatar
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    Quote Originally Posted by HDNitehawk View Post
    My opinion is that if you have a select purpose to use the 2x and have time to arrange it it could be used. But on the fly you could crop and accive close to the same results.
    Agreed. I only occasionally travel with the 2xTC anymore and the couple times I used it were for tests. Whereas I use the 500 II native or with a 1.4x TC all the time. Both those results are stellar, IMO. I do see a noticeable drop off in IQ, but it is still capable. Rather, the two main issues I have are AF speed and once need a 2x TC on a 500 mm lens, your subjects are so far out there that even atmospheric effects come into play.

    I do wonder if I owned a 300 f/2.8, for example, if I would use it more. But, as it stands, it is a piece of glass I am not sure if I would buy again.

    Not surprised, but I am glad to see the 500 II hold up. Granted, I think the sharpest image is the 600+1.4xTC. Again, not surprised, but looks like you have a great lens in your hands.

    Thanks for the tests. It is interesting.

  8. #8
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    Quote Originally Posted by Fast Glass View Post
    Lol, right!

    I do get the logic, and it is fair assumption. But sometimes trying to mimic real world scenarios don't make it easy to narrow in on a particular thing we are trying to test. In this case sharpness.

    To be fair, I wonder about the 2X extender results. Maybe sample variation or sometimes even 1/500 is not fast enough, maybe just a tiny bit OOF. I have been known to flub manual focus too once in a while.

    I just have a hard time accepting that the 2X is worse than cropping, lol. Because it would have to very soft to throw away all the sensor resolution and still come out on top. Not necessarily doubting your trials though. There could be other reasons for it.

    I'm trying to edit the samples you gave, but for some reason DPP won't edit the files. I can't do any general adjustments for some reason.

    I was gonna try my hand at getting all the white balances good, correct for all lens defects, use lens optimizer to apply CA and correct for lens abreactions/corner sharpness, any extremely minor noise reduction if necessary and sharpening to taste. As if it was a real photo. Just your basic run of the mill postprocessing.

    And see with real world post processing how it turns out. And much easier to see the sharpness difference without the WB shift and exposure difference.

    Actually it be nice to play with the RAW files altogether. LOL.
    Neuro had posted his findings on EF vs RF and he felt the RF extenders were softer.
    If his findings are correct then that might be some of it.
    It might be that I had a bad copy.
    One of the things I do also is compare from reviews, things that Bryan has said, and look at the charts and see if the differences I am seeing from one similar lens to another. In this instance I looked at the 500mm vs the 600mm, granted not identical but it gives you an idea.
    https://www.the-digital-picture.com/...mp=2&APIComp=0
    After all that I do believe I was seeing an accurate representation.
    I also had 2 sets of RF 2x pictures, only the best picture out of the best set was used. WB is off on the RF 2x because of the type of lighting to get the ISO down.

    The pictures were screen shots done on the fly at the office.
    I have the JPG here at the office and if you want I could put them in a drop box and shoot you a link.
    Or I could even forward them.
    If you want them shoot me an message with your email address.

  9. #9
    Senior Member Fast Glass's Avatar
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    Yes! I would like that, see how they hold up to post. Maybe their is some details than can be resurrected.

  10. #10
    Senior Member Fast Glass's Avatar
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    But yes they look pretty similar, but still with critical sharpness any amount of error, and it doesn't take much, could introduce softness.

    I was just reading up on how Bryan does his crops because I'd like to so something similar for my own uses. As I'm sure you know it is pretty involved and he goes through a lot of effort to get some really clean results. Just one of the things he does is shoots remotely via computer monitor and focuses and refocused as much as 15 or 20 times! And then picks out the very best. I can see where just using the back of our cameras not being scientifically accurate or consistent enough to trust it 100%.

    Or even the chart itself, it's a very finely printed one at 4000 DPI. Smooth texture. Large. Mounted on a 1/2" glass. Laser aligned ect. Definitely makes me apriciate the work that went into these crops.

    Maybe your shots are representative, I can't really say. And you don't necessarily need to go to quite that far to know if your lens is sharp. But it sure does rule out a lot of variables.

    Just food for thought. Your 2X ones are the only ones that seen quite soft to the point I do question them. I feel they are just soft enough where they are on the level or very slightly worse than the cropped image. And it would take very little to make it that way. Even just 10% sharper would make them slightly better than cropping. And then I could sleep at night.

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