A polarising filter! I used a ND 10 stops vario filter and 1/4000 f8. A rather graphic result.
Your Canon is with mirror I believe. I didn"t deer to use the Z6III mirrorless since the sensor is directly exposed. So I used the D750 with mirror.
I didn’t prepare well but my goal was a timelap. I didn’t succeed. But a wonderful day. With falling stars in the night.
Looks overexposed. The polar filter doesn’t add anything to the exposure. When I’m right a solarfilter is about 14 18 stops. Or more.
This one is also overexposed. The ND filter wasn’t positioned maximal. Took a while before I noticed.