Theres a lot of bias for full frame over APSC. I use both formats. R5-R7. Plus Rf 24-105 F4, Rf 100-500 and Sigma 10-18 F2.8-18-50 2.8. The Sigma glass, really makes the R7 a complete kit. Birding with the R7 and 100-500, even in low light is pure joy. one shot at a time, with continuous AF. plus, ES. The R7 is one of those rare cameras That make photography a fun hobby. The R5? Also, a great camera for birds and do it all kit. RJ