Oh guys, I think I get what you're talking about. At least I hope so.
Yes, it is about contacts. But apparently not about their resilience.
Something did not give me peace and I did not want to start remaking the Kenko rings.
I looked on the Internet and noticed that Kenko has 7 electrical contacts. But Meike has 8. I looked for the reason why, and what the contact was responsible for.
I found it on a site.
The eighth contact is responsible for the ground of the AF-S lens. The seventh is ground, but the eighth is stated to use AF-S lenses.
And I have AF-S lenses in my possession. It will be good if that is the solution. I didn't pay attention to it until now, but I tried to find the reason. In a few days I will order Meike and see what happens.
Of course, I will inform you in any case. So that you also have information for sometime if you need it.
Contact information from the site. I do not list the site so that it is not an advertisement.
1. VCC (power)
2. RW or H/S (read/write) (becomes RW1 if teleconverter is used)
3. LCLK (serial clock) (becomes LCLK1 if teleconverter is used)
4. LIO (serial data) (becomes LIO1 if teleconverter is used)
5. (teleconverter use) RW2
6. (AF-S use) LBAT
7. PGND (ground)
8. (AF-S use) PGND (ground)
9. (teleconverter use) LCLK2 (serial clock)
10. (teleconverter use) LIO2 (serial data)
The odd teleconverter extra (all the "2") signals allow the lens to talk simply through the teleconverter. The teleconverter only responds to the lens with a 1.25, 1.4, 1.6, 1.7, or 2x value, which the lens then processes and alters the focal length and aperture parameters in communicating with the camera on the main signals ("1" signals).
The full AF-S focusing protocol is described in US patent 5727241.