Fuji 50-140mm Aperture Issues

[KurtHoyle]

Hi folks,

does anyone know what might be the cause of this issue?

Fuji X-T1 and 50-140mm...

Aperture on lens is at f8...

X-T1 is displaying the aperture to be f7.1...

It's doing this on 2x different X-T1's 

[Max_Elmar]

Does it change when you spin either control wheel? They can be set to override the aperture ring control. Easy to knock out of place. 

[Phil]

Is the issue just with f/8, or is it with all apertures? If it's with all apertures settings, is it consistently off by 1/3 of a stop?

 

The aperture ring works via a position sensor. So you set the aperture you want, and the lens reads the position of the aperture ring, and tells the camera to use that aperture setting. IIRC, the position sensor is just a little thing mounted to the inside of the barrel (and the inside of the aperture ring has a row of markers), so my guess is something got bumped out of whack with those.

 

If the discrepancy is consistent, that would seem like a sensor issue, and if it's just the one aperture setting, or if it's random, it's probably the markers inside the aperture ring.

[joshhhab]

Hope it is definitely something with positioning sensor that is simply variable resistor

[Aswald]

Probably the contact on the tracer getting out of whack. Crosstalk from grease+metallic powder?