initial findings

aperture.md

@@ -0,0 +1,12 @@
+# Aperture messages
+## Control (from Body to Lens)
+Example message, space separated header, payload and checksum:
+```
+f02000018503 3f7500001400141c0000020101030002010000002f1516 050255
+```
+| payload byte no. | vales, meaning |
+| ---------------- | -------------- |
+| 1 | changes when focusing: 1d = AF, 4C = MF, 3F = when no focus is done |
+| 4,5 | aperture control range: 1413 for F2.8 -- f417 for F16 |
+| 6,7 | same values as 4,5 |
+| 12,13 | each oscillate between 00 and 01, so I use them as odd or even counter |