I've always had a very limited budget. And I either won cameras in competitions, or the manufacturer provided them to me (either for free or with significant discounts). When it came time to change my old Canon, I tried to negotiate with Canon. But it didn’t work out. At the same time, Sony was committed to cooperation. And in addition, I won a Sony camera with one lens. I wanted to smoothly switch to Sony optics. Temporarily using your old lenses through an adapter.
The plan was quite workable, the costs were only for the box itself.
But as I used it, I began to doubt it. For 3 years, Sony has not released a fisheye. The macro wasn't as good as I wanted. I started making a lot of videos. And I also didn’t really like the video on Sony (7R3).
Therefore, when I had the opportunity to sell Sony, I did it. And with the money I received I bought a Canon R5 and box for it.