The glass I use is the same that has been successfully tested by many directors, some of them wanted to share their work with me and are those videos that you can see in the project description.
Metabones glasses are undoubtedly the most famous but also the most expensive, some of them, however, have a strange behavior, that is if it is true that with large openings they maintain an excellent sharpness, it is also true that with fewer openings (usually from f2.8 to f4, the ones commonly used) can lose sharpness thus degrading the image.
Watch this video: https://www.youtube.com/watch?v=qKjgh-8tAQA
The glasses that I use instead, do not suffer from this disorder, they maintain a constant quality, both in the center of the image and in the corners, working very well from F1.8 onwards.
The F1.4 aperture is the limit that I do not recommend to overcome because the lens will work with an extreme F1.2 width.
I also want to remind you that, the UV-IR cut filters mounted on Blackmagic cameras are not of excellent quality, it is known that they degrade the image in sharpness and do not have a clear cut of the IR frequencies, my filter in fact, mounted on the Magicbooster Pro, increases image sharpness even with the use of focal reducer glass.