Will the EF 500mm f/4L IS USM II replacement for the RF mount be a zoom?

Jul 21, 2010
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If there was an EF 100-300/2.8 it would be much more complex and heavier than the RF 100-300/2.8. The fact that the sensor is closer to the back side of the lens allows better optics with less glass.
Even with the advantage of a shorter flange distance, the RF 100-300/2.8 is heavier and longer than the EF 300/2.8 II. That was my point, and a hypothetical EF 100-300/2.8 is irrelevant to it. I’d agree that an RF 200-500/4 could be lighter than an EF 200-500/4, but that’s also irrelevant.

How does the shorter flange distance support the idea that an RF 200-500/4 will be lighter and/or shorter than the EF 500/4 II, given that the RF 100-300/2.8 is neither compared to the EF 300/2.8 II?
 
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AlanF

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Aug 16, 2012
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If there was an EF 100-300/2.8 it would be much more complex and heavier than the RF 100-300/2.8. The fact that the sensor is closer to the back side of the lens allows better optics with less glass.
Why would the EF be much more complex and heavier?
 
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Jun 29, 2016
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Why would the EF be much more complex and heavier?
It is due to the fact that you need to keep light refraction in different wavelengths to reach longer distance, the longer the distance, the more elements you need to correct the recitative indexes (for similar F number). This is how a 100-300 F2.8 zoom can be as heavy as 300 F2.8 lens.
 
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AlanF

Desperately seeking birds
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Aug 16, 2012
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It is due to the fact that you need to keep light refraction in different wavelengths to reach longer distance, the longer the distance, the more elements you need to correct the recitative indexes (for similar F number). This is how a 100-300 F2.8 zoom can be as heavy as 300 F2.8 lens.
You wrote that an EF 100-300/2.8 would be more complex and heavier than the RF 100-300/2.8, and I asked why to that. The small difference in flange - sensor distance is going to have only a a marginal if any effect for a telephoto lens - the lens has to be corrected for the same virtual 300mm path length for both ends of the spectrum independent of flange distance. Now you are talking about vs a 300mm lens?

If there was an EF 100-300/2.8 it would be much more complex and heavier than the RF 100-300/2.8. The fact that the sensor is closer to the back side of the lens allows better optics with less glass.
 
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Jan 27, 2020
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I have been using my 12lb EF400 f/2.8 IS USM since 2004. While I used to use it handheld, after nearly 20 years I struggle to lift it (when mounted to mono or tripod) anymore. I have been waiting for the RF 500 f/4 since the R5 came out, and will be disappointed (and not buy it) if there are major compromises to make it a zoom, as I have two other lenses to cover the shorter focal lengths.

I want the best combination of image quality, focus speed, weight, and reach with no compromises for zoom. For me, this will justify the price, especially when considering a high res version of the R5 on the horizon.
 
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