Questions about Canon RF 100-400mm f/5.6-8 IS USM

The RF 100-400mm f/5.6-8 IS USM lens is compatible with the Canon EOS R50. Although this lens is designed for full-frame cameras, the R50 also uses the RF mount, making it possible to use this lens without any problems. The Canon EOS R50 is an APS-C sensor camera, but it is compatible with all RF lenses, including those designed for full-frame formats. This means you can take advantage of the versatility and reach of this lens for nature photography or events such as air shows.

The lens has an RF mount and the EOS 800D has an EF mount. It seems to me that there is no adapter in that sense. So I'd say it's not compatible.

No, the lens has an RF bayonet and only fits on mirrorless cameras

Hello. I have an ef 70-200 f4 lens, its lens hood fits rf 100-400 👌🏼 I took a regular protective filter, 67 mm

No, not possible and not with any adapter. RF lenses are designed for R cameras.

Yes, can be used with the R7 without any problems.

No! This is an RF mount lens and only fits the new mirrorless Canon with RF mount.

Yes

Unfortunately not, it is an RF mount for the EOS R system whereas the EOS 70D has an EF/EFS mount.