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Some UK prices for new RF lenses (85mm, 600mm, 800mm, 100-500mm) leaked
(07-09-2020, 10:46 AM)Klaus Wrote: I have no issues whatsoever with the specs. They are very reasonable for a certain usage pattern.

However, it has to be said that 500mm f/7.1 is diffraction-limited on the EOS R5 - or to phrase it differently, it'll not out-resolve the sensor regardless of how good the design is.
Theoretically, things go downhill from f/5.6 on this sensor (red light at f/5.6 on FF: 38mp max).

That's still all fine ... but not at 2899GBP. Well, we'll know in an hour. Maybe it's a typo and it's 1899GBP.

BTW, regarding the 600/800mm f/11. For green/yellow light, they have a max theoretical resolution of 16mp (red light: 10mp) - thus they are really more for the R6.

I'd really like to know how you calculate this, Klaus.

According to my calculations, based on Norman Koren's equations, MTF-09 (Rayleigh) for green light results in a sensor diffraction limit of F/14.1, which is where lens diffraction equals sensor diffraction.

As to max. resulting MP: that also depends on Demosaicing and AA-filter liosses, which for Canon is estimated to be about 30%.

System result for red light therefore is by definition less than 38 MP too, because the maximum system resolution would be around 38.9 MP MTF-09 for green light (512 nm) with a 100% corrected lens at F/1.

Thank you in advance.

Kind regards, Wim
Gear: Canon EOS R with 3 primes and 2 zooms, 4 EF-R adapters, Canon EOS 5 (analog), 9 Canon EF primes, a lone Canon EF zoom, 2 extenders, 2 converters, tubes; Olympus OM-D 1 Mk II & Pen F with 12 primes, 6 zooms, and 3 Metabones EF-MFT adapters ....

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RE: Some UK prices for new RF lenses (85mm, 600mm, 800mm, 100-500mm) leaked - by wim - 07-09-2020, 11:34 AM

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