Canon RF 100-300 f/2.8 IS USM

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Originally Posted by neuroanatomist

Here's a quick comparison, and I think the 100-300/2.8 + 2x holds up very well compared to the 600/4 II. The 100-500 is no slouch, either...

https://www.canonrumors.com/forum/th...-is-usm.42653/

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In those images, I would agree. Those are more of a "bird-scape" style .... my preference with birds to have the subject much bigger in the frame in which case the new 100-300 with the 2X TC may do just fine. Since I already own a 600 f/4 and the RF 100-500 it's not really a lens that's on my want list although it is clearly a stellar piece.

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Originally Posted by Joel Eade

In those images, I would agree. Those are more of a "bird-scape" style .... my preference with birds to have the subject much bigger in the frame in which case the new 100-300 with the 2X TC may do just fine. Since I already own a 600 f/4 and the RF 100-500 it's not really a lens that's on my want list although it is clearly a stellar piece.

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If not for this contrived 'test', I would not have brought the 100-300 on a birding outing at all. Outside of testing of this sort, doubt I'll use it with the 2x TC in the future. I can see using it with the 1.4x TC for outdoor field events, a 140-420mm f/4 zoom will be useful in that setting, and under non-pro field lighting the 100-500mm needs ISOs of 12800-25600, so the extra 2/3 – 1-2/3 stops of light will make a meaningful difference.

Makes complete sense to me!

Thanks John.....I came across these two images of Bryan's (here and here) with the 100-300 f/2.8 with a 2x TC which are plenty sharp, IMO. The typical fall off in IQ with a 2x TC does not seem to be happening here. But, I was wondering how fast the AF is? Do you see the usual fall off in AF?

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Originally Posted by Kayaker72

Thanks John.....I came across these two images of Bryan's (here and here) with the 100-300 f/2.8 with a 2x TC which are plenty sharp, IMO. The typical fall off in IQ with a 2x TC does not seem to be happening here. But, I was wondering how fast the AF is? Do you see the usual fall off in AF?

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I think it slows down a little with the 2x, but the AF is so fast natively that any difference is barely perceptible.

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Originally Posted by neuroanatomist

I think it slows down a little with the 2x, but the AF is so fast natively that any difference is barely perceptible.

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Thanks. This seems like a big improvement over previous lenses, especially EF, with a 2x TC. It'll be interesting to see about AF speed and IQ if Canon does release some sort of 0, 1.4, 2x TC.

This link is a set of shots from r5. And the 100-300, as well as with the 1.4 and 2 x TC at max aperture. 100, 200, and 300 zoom points.

My conclusion is leave the TCs off. Really surprised that 'bare' with 200% was better. Somewhat concerned about Canons QC given the differences in performance of the 2 copies of the wide angle zoom.

Given the abilities of topaz (reportedly as I have yet configure my copies succesfully) thinking both of the TCs are going back.

Thoughts?

https://drive.google.com/drive/folde...9TjrtTMhQz9iu1

Thanks Mike.

Do you have a cheat sheet as to which is what?

images are in order of 300mm 200mm 100mm and naked, 1.4 then 2.0 Tcs. They were all taken in a max apeture so you can tell by the focal length f stop in the exif info

I compared the 600 f/5.6 to the 300 f/2.8, looking at the sign at the entrance to the men's room. The 600 mm version looks sharper than the 300 mm cropped to the same size. So from that simple test, it seems the 2x teleconverter is working well.