Report: The RF 200-500mm f/4L IS USM is delayed until 2025

kaihp said:

What I've found is that the EF 200-400 (and the EF 300) autofocus better/faster than the RF 100-500 (see thread).

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My experience, in general, has been that AF performance is strongly correlated with the amount of light let in / max aperture. I.e., I don't find it so surprising that f/4.0 and f/2.8 lenses perform better than the RF 100-500 @ 4.5-7.1.

Even if I'm not shooting wide open (though I usually am), it has seemed to me the AF system is using the additional light that is gathered for focusing.

[I regularly do paid work with the 100-300, 400, and 600 but have not used the EF200-400. I owned (and sold) the 100-500... I just never seemed to get great results with it in any situation with less-than-ideal light. I know there is a ton of love for that lens.]

I'm intrigued by the 200-500 but don't know if I would purchase it. If I were to purchase, I'm not sure what I would then sell of the 100-300/400/600.

I think the current EF 500mm f4 LIS II was a nice sweet spot in portability, price point and results. We never saw a mk III version of this lens on the EF mount and never will. But Canon could have made a mk III with all of the weight savings and the other mkIII superwhites offered. However, with the advent of the mk III 400/600 offerings...the portability / results are superior in those two lenses. So really there was no point in a mkIII 500/f4.

This new Zoom is probably going to be heavier and considerably larger than the mk II prime. However it's really creating an entire new genre / market for it's self. A super mind boggling versatile lens that really offers an impressive array of useful features. I can see this being a VERY popular lens on wildlife workshops. However, it's not going to be small or particulary light....or cheap.

Chig said:

I'd suggest 200-800mm f/5.6 would be much better, especially if it was variable f/1.4-5.6 if that's feasible?
Don't understand why they don't make the pro zooms variable, why not a 70-200mm f/1-2.8 ?
I realise a constant aperture is good for video and keeping your exposure constant but surely that can no be done with software even if the maximum aperture is variable. I'd much rather have a zoom which uses the maximum entrance pupil at all focal lengths so the 100-300mm f/2.8 could be f/1.0-2.8 and Canon could give you an option in the camera software if you want to lock the aperture at f/2.8 as you zoom.

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If you have a zoom lens, take a look at the entrance pupil of the first optical element inside the lens as it moves toward the front of the lens at the low focal length and moves away from the front of the lens at the largest focal length. Moving forward and back changes the angle of the entering light, allowing the lens to use the width of the front glass of the lens to achieve maximum entrance pupil diameter at the long end because the first optical element is farther away, but as the first optical element moves closer to the front glass of the lens, the angle of entering light makes it impossible to use the full width of the front glass as your "entrance pupil". If you look at a lens it will be clearer than my verbal description.

This 200-500mm f/4 sounds like it will be fabulous for sports and large wildlife but for birds especially small ones a 200-800mm f/1.4-5.6 zoom would be my dream lens (not that I could afford one unless I won a lottery).
I don't know why the premium zooms seem to always be a constant aperture as the wide ends are pretty dark relatively speaking.
The 200-500 f/4 sounds great until you consider 200mm f/4 is kit lens material and my dream lens if it was a constant f/5.6 would only be a 1/3 of a stop brighter than my RF200-800mm f/6.3-9 lens at the wide end.
Imagine how versatile it would be if it was 200-800mm f/1.4-5.6. Sports pros would love it especially at events like the olympics where the lighting at the indoor venues are deliberately kept a bit dark for the TV networks.
A 70-200mm could be f/1-2.8 which would be way nicer than a constant 2.8.
I don't know if there's a technical reason for not doing this but if you prefer a constant aperture this could be controlled by software if needed without crippling the potential for those wanting the maximum possible brightness/bokoh.

Quack said:

If you have a zoom lens, take a look at the entrance pupil of the first optical element inside the lens as it moves toward the front of the lens at the low focal length and moves away from the front of the lens at the largest focal length. Moving forward and back changes the angle of the entering light, allowing the lens to use the width of the front glass of the lens to achieve maximum entrance pupil diameter at the long end because the first optical element is farther away, but as the first optical element moves closer to the front glass of the lens, the angle of entering light makes it impossible to use the full width of the front glass as your "entrance pupil". If you look at a lens it will be clearer than my verbal description.

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Thanks for the explanation so sounds like not my idea isn't fully achievable but surely a variable zoom which comes as close to what is possible would still be better than a constant aperture for example the 200-500mm could be f/2.8-4 and my proposed 200-800mm could be f/2.8-5.6?

upallnight said:

My experience, in general, has been that AF performance is strongly correlated with the amount of light let in / max aperture. I.e., I don't find it so surprising that f/4.0 and f/2.8 lenses perform better than the RF 100-500 @ 4.5-7.1.

Even if I'm not shooting wide open (though I usually am), it has seemed to me the AF system is using the additional light that is gathered for focusing.

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Good point and that is my experience too. But since I'm not a pro, I have not put too much validity into my results and blaimed my lack of skill and experience.

Motorsports is fortunately usually run outside with reasonable to good/excellent lighting, but with an AF system that gets a good workout from having to follow the trajectory of the subject.

kaihp said:

Good point and that is my experience too. But since I'm not a pro, I have not put too much validity into my results and blaimed my lack of skill and experience.

Motorsports is fortunately usually run outside with reasonable to good/excellent lighting, but with an AF system that gets a good workout from having to follow the trajectory of the subject.

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No... it's definitely the case. The max aperture of a lens certainly affects its AF performance, even if shot stopped-down.

Your post made me think about when I got my first "big white": I thought it would instantly elevate my photography, and I was puzzled (disappointed!) that I did not immediately get tons of keepers. Yes, the lens was way better than what I was used to, but I didn't know how to use it. Hell, I still have some times where I blow the shot if I get lazy!

Anyway, I'd bet you are being modest about your skills. I'm sure if y ou tossed me into a motorsports situation I would not do well/know how to make the most of the panning features. Not sure my experience shooting wildlife and ball sports would translate — doesn't matter that I'm paid to do it.