MOD - Click stop aperture - Viltrox 56mm F1.4 lens Fuji X mount

 Today I’m slightly modifying Viltrox 56mm F1.4 lens to add aperture ring click-stops.

It’s less expensive to produce lens without aperture ring click-stops and just saying “Aperture is click-less for smooth video shooting”. However many photographers prefer to have firm clicks when rotating aperture ring.

Viltrox 56mm F1.4 is a lens with electronic contacts, autofocus and external aperture ring control that is operating physical aperture also electronically. If you check my disassembly article of Viltrox 56mm F1.4 lens, the aperture ring position is detected by special strip that most likely acts as a resistor. So lens electronics knows external ring position and digitally signals aperture engine to changes aperture diameter.

One of positively surprising thing about Viltrox 56mm F1.4 lens is – the internal lens frame already has two aperture click-stops created by factory – at F16 and “Auto” positions. There is spring loaded 2mm bearing ball that is catching slots from the inner side of the aperture ring.

Because most challenging to add mechanics for click-stops is already there, my first step is to mark future position of F stop values, by rotating aperture rings to different markings, and adding a scratch line near the edge of spring loaded ball. After marking all desired positions and removing aperture ring from the lens it will look like below.

Then I’m using hobby knife to make deeper markings in the inner wall of aperture ring, and finally using triangular metal file to grind that positions.

I was initially planning to also add 1/3rd F stops like it’s done in Fujinon lens, but then decided that full stops are more preferable for my shooting style.

So after grinding full stop positions, I’m wiping out all the aluminum debris.

Then I’m assembling the lens back and checking how the aperture ring operates. Nice, it has very noticeable clicks at full stops now, just like any other Fujinon lens do. Taking few test shots to see how lens performs. Firs shot at F2, which I selected by blindly rotating aperture ring until the first click, and yes – Fuji X-E2s camera is also showing F2 in viewfinder.

One more shot at F1.4.

Finally I used red paint to mark 1/3rd stops on the ring, just to indicate which positions are clickable. I’m happy about the results. It will be interesting to check if Viltrox 23mm F1.4 and 33mm F1.4 also have built in factory click stops at F16/Auto, and if it’s possible to modify that lens as well. For now I don’t have that samples to confirm.