Camera board • Re: Using HQ Camera with Motorized Lens: Autofocus Integration Tips?

I’ve written an autofocus program (rpicam-focus) based on rpicam-vid and rpicam-hello, which actually works really well in good lighting conditions. If I could also access the bit-coded information from the M3751F8HP MCU, the setup would be perfect. I don’t need the entire S**Y A-Mount protocol—just a dedicated command set to query the lens position would be enough for me.

I need to access this bit-coded information from the slip contacts. I think it uses the SIP protocol; I had no success with I2C. It’s electro-mechanically brilliantly simple—the contacts reveal the zoom position of the telephoto lens, which allows the autofocus to quickly move into the predefined range for that position and then do its fine positioning using CDAF/PDAF.

I’ve already considered replacing the chip, but ideally, I’d like to have an adapter that works with these lenses without any modifications. The combination of the IMX477 sensor and the SIGMA APO DG 70-300mm is simply brilliant—that’s equivalent to a full-frame focal length of over 1500 mm!

4-bit coded positions:
1110 = 70 - 85 mm
0110 = 85 - 100 mm
0010 = 100 - 115 mm
1010 = 115 - 130 mm
1000 = 130 - 145 mm
0000 = 145 - 160 mm
0100 = 160 - 175 mm
1100 = 175 - 190 mm
1101 = 190 - 205 mm
0101 = 205 - 220 mm
1001 = 220 - 235 mm
1011 = 235 - 250 mm
0011 = 250- 265 mm
0111 = 265 - 300 mm

https://partsearch.io/renesas/m37516f8hp-u2/

Statistics: Posted by kletternaut — Mon Jun 02, 2025 9:33 pm

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