p.1 #1 · Help - Voigtländer 40mm f/1.2 Z – aperture reading changes with focus distance / stuck at f/1.2
I’m using a Voigtländer 40mm f/1.2 Z on a Nikon Zf and recently noticed a strange aperture-reporting issue. It's worked fine in the past ~1.5 years I've owned it, but after re-mounting today I've had this strange issue with aperture readings. Lens was stored in a dust and moisture-free environment, zero drops/bumps.
The physical aperture works correctly, aka the diaphragm physically opens/closes normally when I turn the aperture ring, but the Zf’s displayed aperture depends on focus distance.
What I’m seeing:
From ~0.3 m to ~0.75 m, the camera reports the correct aperture.
Around ~0.75 m, the displayed value starts fluctuating.
Example: with the lens physically set to f/10, the Zf may briefly show f/9, f/6.7, f/4.5, etc.
Past ~0.75 m toward infinity, it usually drops to f/1.2 and stays there, regardless of the actual aperture setting.
Focusing back closer restores the correct reading.
Other checks:
Lens is correctly recognized as 40mm
Focus confirmation/peaking work normally
Contacts have been gently wiped down
My Nikon Z 26mm f/2.8 and 24-120mm f/4 S work perfectly on the same Zf
Swapped batteries, updated FW to 3.01
So this seems lens-specific and possibly related to the internal aperture sensing/flex circuitry.
Has anyone else had this happen with the Z-mount 40mm f/1.2? If so, were you able to get it repaired, and what ended up being the cause?
