Keep the Hood On: Slim UV for Leica and Voigtlander

Yes—you can keep the original hood on. But only if the UV filter frame is genuinely slim and the threads are cut clean. Screw on a generic, thick clear filter, and that factory hood gets kicked straight off the lens.

I'm Leo Liang. I make filters at XT Filters, but I still spend most mornings walking city streets with a rangefinder slung over my shoulder. I lose count of how many times I've watched someone stand on a freezing sidewalk, wrestling with a vintage metal hood that won't click because a chunky filter ring stole two millimeters of clearance. It wobbles, sits crooked, or drops off when you brush against a doorway.

This post is about that solid mechanical click. It's about finding a Leica 39mm slim UV filter hood setup that actually locks home—not adapters for a Fuji X100, and not 49mm rings. Just native 39mm lenses and the factory hoods made for them.

The hood is doing more optical work than the filter

A clear filter is honest insurance. It takes the hit from greasy fingers, dust, and rain. Useful. Boring.

The hood is what protects your image.

Classic Leica M and Voigtlander lenses—from a 35mm Summicron or 50mm Elmarit to a compact Voigtlander Color-Skopar—have front glass sitting dangerously close to the bezel. The minute the sun slips off-axis or a street lamp cuts across the frame, contrast drops off a cliff. Deep blacks wash out to milky gray. A proper hood saves that contrast. Mechanically, a rigid metal hood also takes the doorframe hits.

If adding a filter forces me to leave the hood behind, the filter stays in my bag. The goal is getting front-element armor without sacrificing flare control.

Thick rings are why hoods refuse to lock

When a hood won't seat over a filter, nine times out of ten it's ring thickness.

Most generic filters are built for bulky autofocus zooms. Their frames stick out past the lens rim by four or five millimeters, finished with fat knurling. On an SLR zoom where the plastic hood bayonets onto the outer barrel, that bulk goes unnoticed.

On a compact 39mm rangefinder prime, it ruins everything.

Leica’s classic hoods—like the clip-on vented 12585 or rectangular squeeze shades—and Voigtlander screw-in hoods rely on hair-thin clearance. They expect the rim to sit bare.

Screw in a thick UV, and the hood bottoms out against the filter's outer bezel before reaching the barrel groove. Or it perches cockeyed, resting on friction alone until a quick bump knocks it loose.

A true slim L39 frame strips that bulk away. It sits tight against the thread shoulder so the hood slides straight past the ring and snaps into the lens groove.

39mm rangefinders, not the Fuji X100 trap

A quick detour, because my inbox sees this mistake weekly: 39mm on a Leica or Voigtlander is not the Fujifilm X100 story.

Lenses stamped Ø39 or E39 have native 39mm threads cut directly into the barrel. The filter screws straight in.

An X100 has zero native filter threads. Using a filter on an X100 means removing the front trim ring and adding an adapter ring that steps out to 49mm.

If you're shopping for an X100, do not order a 39mm filter. It won't fit. This size is strictly for native 39mm screw-mount and M-mount lenses.

What I run on my 39mm lenses: XT995PRO

When I need clear glass that lives permanently under a factory hood, I screw in the XT995PRO L39 Black UV in 39mm.

We machined this specific 39mm frame with an ultra-slim profile so it won't steal clearance from factory hoods. The aluminum ring has a matte black interior to kill internal bounce reflections, and the optical glass cuts UV haze while staying dead-neutral across visible light. Once threaded down, the lens profile barely changes. The original Leica clamp-on or Voigtlander hood mounts over it exactly like bare glass.

One field rule: do not stack filters under that hood.

Don't tuck a black mist or polarizer behind a clear filter on a daily walk. Stacking two rings pushes the front out by eight millimeters. The hood won't grab, and on a 28mm or 35mm lens, you will vignette your frame corners. Keep the daily setup lean: one slim clear filter, factory hood locked tight. If you need a CPL for water reflections, swap it bare for the shot, then put the hood back.

Testing fit before stepping outside

Don't test hood clearance in a windy parking lot with numb fingers. Check it at home on a clean table.

Spin the slim UV into the 39mm barrel. It should thread smoothly without resistance. If it binds in the first quarter-turn, stop. Never force aluminum threads into vintage brass or aluminum barrels—back it off, find the thread flat, and turn it down flush.

Next, mount the factory hood. A clip-on hood should snap into its groove with the exact crisp detent you get on bare glass. A screw-in shade should seat to its index stop without binding early against the filter frame.

Give the hood a firm wiggle check. If it rocks, feels spongy, or spins past its stop, the fit is off. Stop and inspect the rim.

If a filter ever fights your factory hood, ditch the filter and keep the hood. Flare ruins frames instantly; clean front glass won't salvage a washed-out shot.

If you need front-element protection that lets your original hood click home, get the XT995PRO L39 in 39mm. Just confirm Ø39 is engraved on your lens before ordering.

— Leo Liang