Excuse my ignorance, but I feel like I am missing something. The new adapters for the RF mount state that it can take EF-S lenses. However, I thought EF-S lenses were only for crop sensors. How can a full frame sensor use a EF-S lens?
I remember Rudy Winston in one of the introductory videos of EOS R system said: "When attaching an EF-S lens via any of Canon’s new R-series mount adapters, the EOS R automatically switches to APS-C crop mode". If correct, it should be around 18Mpixel still picture. Can it be done using 3rd party lenses such as Sigma 18-35mm f/1.8 DC? Not sure. Perhaps the new communication protocol and connection pins play a role in this.Excuse my ignorance, but I feel like I am missing something. The new adapters for the RF mount state that it can take EF-S lenses. However, I thought EF-S lenses were only for crop sensors. How can a full frame sensor use a EF-S lens?
I remember Rudy Winston in one of the introductory videos of EOS R system said: "When attaching an EF-S lens via any of Canon’s new R-series mount adapters, the EOS R automatically switches to APS-C crop mode". If correct, it should be around 18Mpixel still picture.
Yes, you are absolutely right.Yes, except that the pictures will be about 11.8Mpix. Remember, you have to square the crop factor.
From what I understand, it will use the center 40% of the sensor and take still images when an EF-S lens is mounted.... It will be interesting to see if this function can be modified in the menus, as (for example) I can use a Tokina 11-66 F2.8 crop lens on a 6D2, and at 16mm it covers the full sensor...Interesting. Is it only for 4k video? It is capable to take a cropped picture with EF-S?
Thanks
Check page 82 of the manual. When a EF-s lens is mounted, it uses a 1.6 crop and options to use other crops are disabled. So if your 3rd party lens tells the camera that it is a EF-s lens, it should set the crop and you cannot override it.From what I understand, it will use the center 40% of the sensor and take still images when an EF-S lens is mounted.... It will be interesting to see if this function can be modified in the menus, as (for example) I can use a Tokina 11-66 F2.8 crop lens on a 6D2, and at 16mm it covers the full sensor...
Check page 82 of the manual. When a EF-s lens is mounted, it uses a 1.6 crop and options to use other crops are disabled. So if your 3rd party lens tells the camera that it is a EF-s lens, it should set the crop and you cannot override it.
The EF lens interface is a bidirectional serial bus. The definition of data content is in the realm of software and may very well have evolved over the time.
Nevertheless, it appears that EF lenses send their identifier to the body, and the body firmware has a lookup table with the details of all genuine EF lenses.
I don't think that the lens actually tells the camera it is crop, this wouldn't have been built into the original EF protocol because there was no EF-S at the time. What's more likely is that the camera checks for 'EF-S' in the lens name, which would make it likely that third party lenses wouldn't automatically crop.
Here are some typical lens ID codes. If there is no matching code in the camera, it will not know which lens is mounted. For example, tag 183 is for a Canon 100-400mm L. Several 3rd party lenses also send tag 183 to the camera. I don't know if they add the suffix (183.1, 183.2, etc)
EXIF Lens Tags for Canon