MOD - stronger aperture clicks - Fujinon XF 14mm F2.8 lens

Fujinon XF 14mm F2.8 is a great ultra wide angle lens with excellent optics and very high IQ. Mechanically it’s also constructed very well, though there are minor things I’d like to work a bit different. And the aperture click-stop at F2.8 is one of them. It just happens too often – aperture ring gets accidentally rotated without me noticing, and pictures are taken at slightly closed aperture. So how to fix that?

One way to deal with a bit loose aperture ring – is to make the rotation more tight, and I already explained that fix in Fujinon XF 14mm F2.8 lens aperture tightening article. But what if you like the ring to keep rotating easy, and just make F2.8 click stop stronger, like in A (auto) position?

I’m going to explore aperture click-stops and modify F2.8 click-stop location to accomplish that.

First step is to remove lens mount ring, which is explained in the article mentioned above. After that I’m unscrewing three tiny bolts holding the ring with “14” number, and removing it.

Then it’s time to unscrew bolt holding aperture contacts and pull them out accurately.

Now you can remove the aperture ring. There is a tiny metal ball loaded by spring, which is performing click-stops catching.

At this point you have access to the brass plate with click-stop locations. Unscrew three tiny bolts securing it. Then slightly elevate that ring, but don’t remove it – aperture contacts board is protruding and doesn’t allow to pull out that ring, but it’s fine. For this mod you can keep it there and just slightly elevate while modifying F2.8 location.

Closer look at click-stop locations shows that rectangular sockets have different size:

  • A (Auto), marked with green arrow, it’s the widest socket
  • Full Stop, marked with red arrow, it’s noticeably smaller
  • 1/3 Stop, marked with yellow arrow, it’s even smaller than Full Stop

My goal now is to make Full Stop socket of F2.8 little wider, so metal ball will be catching that location stronger, like in A (Auto) location. I’m using paper cutting knife, and accurately cut out small pieces of brass, while keep brass ring slightly elevated. Every time I move brass flake away, to make sure ring remains clean.

Here’s increased size of F2.8 location after cutting (green arrow), comparing to the regular Full Stop size (red arrow).

Finally I’m assembling lens back in a reverse order, and checking how the aperture ring works. Yes, it holds F2.8 aperture position significantly stronger. Now I need to apply noticeable effort to start aperture ring rotation, and it is no more accidentally turning. Problem solved.