True crop factor of the Metabones speed booster 0.71x on the EOS R5

In a previous article I wrote about recording 5K ProRes RAW with the Atomos Ninja V and the Canon EOS R5 by enabling crop mode, but this mode introduces a 1.6x crop, which can be mitigated with the Metabones EF to RF speed booster 0.71x, and by the way, has the same crop factor as the Canon EF-RF 0.71x Adapter.

Just like with the Canon EOS R that has a 1.83x crop, the math should be simple, multiplying the sensor crop factor by the focal reducer crop factor, in the case of the Canon EOS R 1.75x × 0.71x ≈ 1.24x, and in the case of the case of the Canon EOS R5 1.6x × 0.71 ≈ 1.13x, but empirical testing shows that is more like 1.15x

I know, in paper 1.13x vs 1.15x doesn’t look like much, but in practice, it is a huge difference. So after taking some snapshots with and without the focal reducer, there are the visual results, in yellow the 1.13x crop factor:

Also notice, the camera crops while recording UHD instead of DCI:

Leave a Reply

Your email address will not be published. Required fields are marked *


Better images with the Insta360 X3

While I own several DSLRs and Mirrorless cameras, there are moments during vacations when capturing the entire experience proves challenging. From vast attractions to cramped spaces, some scenes simply exceed the capabilities of traditional lenses. This is where the Insta360 X3 360° Camera truly shines. Although I’m aware that the Insta360 ONE RS 1-Inch 360 […]

iPad + Elgato Cam Link 4K + EOS R5

Since the release of iPadOS 17 on September 18, 2023, some iPads can be connected to any USB video class (UVC) webcam or capture card, which opens the possibility of using the Canon EOS R5 (or any other DSLR/mirrorless camera) as an external camera, connected to an iPad trough an HDMI capture card like Elgato […]