Funleader x Brightin Star XSLIM-M Lens Review

Funleader x Brightin Star XSLIM-M Lens Review

Over the past few years, there has been a remarkable rise in M and LTM lens manufacturers, throwing in with Leica and Voigtlander in an attempt to carve out some space of their own. Many of these lenses lean towards the more affordable side of the marketplace, with TTArtisan and 7Artisan joined by revived "classics" like Meyer-Optik Görlitz or handmade, artisanal lenses like MS-Optics.

Recently, a company known as Funleader joined the fray with a novel set of adaptable lens barrels that allowed for the non-destructive conversion of Contax G-mount lenses to M-mount. These were followed by 18mm f/8 CAPLENS models, and finally, the 28mm f/2.8 Funleader x Brightin Star XSLIM-M.

Externally, this lens is slightly reminiscent of the MS-Optics 28mm f/2.0 Apoquealia. However, I've found those similarities to be largely superficial. While both are very slim pancake lenses and feature identical focal lengths, the XSLIM is made from different materials and has unique characteristics compared to the also-excellent MS-Optics glass.


Let's begin with the construction of the lens. It's heavy — noticeably so, at 125 grams. Made from brass and finished with what feels like enameled glossy black paint, the entire body is only 9.9 mm thick. The lens features markings in both feet and meters, with the latter marked for zone focusing. The minimum focusing distance is 2.3 feet (closer than the rangefinder in my M3 allows) and is rangefinder coupled. The glass itself is small and is constructed from six elements in five groups with 10 aperture blades that go from f/2.8 to f/16.

While this lens is rangefinder coupled, with an adapter it can be mounted on virtually any mirrorless body. For the purposes of this review, I used it on my M3 and my Nikon Z6.


Focusing on this lens is very easy, with a small focusing tab at the bottom of the barrel. There is enough resistance that you can set your focus and not need to worry about it, but not so much that it requires any effort to move it. Adjusting the aperture is a little trickier, as the layout of the lens keeps it on the front and as another outer-barrel ring. This means you need to actually look at the lens while adjusting. While this isn't a significant issue, it is one you should be aware of. 

The lens comes with a solid, screw-on metal cap. I tend to leave it off. However, because the lens is so thin and the front element is exposed, I found myself touching it more than I'd be comfortable with when removing it from my bag. More than anything else, you should be aware of this. A 25.5mm UV filter is a must, but really, you should always have some kind of protective filter on your glass.

On my M3, I found the XSLIM to be very easy to use and wonderful for street photography. You can set it to infinity and stop down the aperture to f/8, and nine times out of ten, you're going to get the shot you want. 

Image Quality

I found the image quality quite impressive. The images were sharp when shot wide open, without any noticeable chromatic aberration or loss of detail. There is some vignetting at f/2.8, but this drops off significantly by the time you hit f/5.6. Shooting at f/2.8, there was some softness at the corners, which, unfortunately, does not seem to sharpen significantly stopped down. The softening at the corners is my strongest criticism of this lens, but it's far from a dealbreaker.

It was generally fairly overcast during the week I was testing, but I noticed no significant lens flare or ghosting. At f/2.8, I found the bokeh to be pleasant, but not overpowering. It was certainly enough to separate the subject from the background, but not enough to be distracting. While this may be an imperfect comparison, the bokeh reminded me slightly of the Leica 40mm f/2; it's subtle, but with a unique flavor all its own.

Comparable Lenses

Only two lenses really come to mind: the previously mentioned MS-Optics Apoquila 28mm f/2 and the TTArtisan 28mm f/5.6. Truthfully, these are three distinct lenses, all with unique characteristics and handling. The TTArtisan is much closer to a "vintage" style lens, and at f/5.6, it handles very differently. The MS-Optics is functionally closer, but the image quality and artisanal approach makes them both rarer and more expensive. All three are excellent lenses, but their differences mean they're going to appeal to different audiences.


The XSLIM-M is certainly unique. It is both affordable, produces high-quality images relative to its price point and is very well made. The construction is sturdy enough to take a beating, and it's easy enough to operate intuitively once you get the hang of it. For a compact, street-shooting bit of glass at an affordable price, this is a great place to start. 

C.S. Muncy is a news and military photographer based out of New York City and Washington D.C. With a passion for analog and alternative formats, he is rarely seen without a full cup of coffee and is frequently in trouble.

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"but really, you should always have some kind of protective filter on your glass." No, many of us prefer to avoid degrading the image quality of our lenses for the sake of "protection." What's the point of having a lens with a pristine front element when it has been making inferior images the entire time?

I mean, you should do what you feel is best, but as someone who tends to shoot in high-impact environments where there's a good chance of the lens taking a hit, I'd rather use a filter.

How many times in your career have you had a lens take a hit?

On the Air Force side? Oh man, I could tell some stories. I learned the hard way that rotor wash will *absolutely* etch unprotected glass. I had a lens get terribly sand-blasted while sitting under an HH-60 during a training event. More than that, when you've got two cameras on harnesses swinging against your body, against each other, and against your other assorted gear. Eventually something's going to take a hit. You can protect it - with filters, rubber lens hoods or protective sleeves, but it's still going to take a beating.

On the news side, I've got similar stories. During protests all kinds of gear is slapping against one another, or against other people. Toss it in your bag and the lens is brushing against a dozen different things. I remember getting a Nikon 24-70 back from NPS, and literally the first thing I did at the DNC was drop it and crack the front element. During more than a few protests I've had people make grabs at my cameras. Some folks used to spray-paint lenses - never had it happen directly to me, but I've seen it done.

For news work, the difference between a shot taken with a filter and one taken without is, for the most part, so small as to not worry about. The difference between a lens element taking a hit and a filter taking a hit though, is well... significant enough.

If going without a UV works for you, by all means keep on rocking on. Who am I to tell you how to take your photos? But for myself, I can't imagine working without one.

You have definitely been in some uncommon circumstances that do indeed warrant a protective filter! Just as there are cases that warrant it, there are many that dont, and so a blanket statement either way, for all people in all cases needing to "always" use a filter, or not, just doesn't apply.

That's fair!

Maybe this should be the subject of my next article.

I have to agree, no filter without a purpose! In the early 80s, I sold cameras at the photo counter of a drug store to help make my way through university. The margin on camera bodies was purposely very slim (to compete with magazine gray market sales) but the margin on film and accessories was very large. so we purposely tried to add on as many accessories with every sale. This is when I first heard the phrase "Keep a skylight or a UV filter on at all times to protect the lens", and I used it often to sell hoya MC filters.

Voice of experience says always put a filter on your lens. If possible, always have a hood on your lens. If your lens/filter never gets dirty or needs cleaned, you aren't using your camera.

It's way cheaper to replace a filter than it is to have etched glass or bent filter rings on a $3,000 lens. I dare any of you to show me examples of a good filter across the front of a lens compared to that same lens with no filter and tell the difference with a commonly viewed image size on paper or a screen. From a purely technical standpoint it is true that anything in front of the lens could degrade the quality but all it takes is a few little scratches or imperfections to degrade the quality of the lens under certain circumstances so pick your trade-off.

There are many examples out there of how even a good filter can create flares and reflections that ruin what would be a perfectly good photo without a filter, just as there are many examples of how a scratch or imperfection won't degrade the quality of a lens.

Why "protect" a lens with a filter that degrades every single photo you take with it? Why downgrade a $3,000 lens when you could just buy several cheaper, lower-quality ones, use them without filters, and toss them if they get damaged?

I've never had dirt on a lens i can't clean off, and if i'm photographing a vehicle that's flinging gravel at me, sure, i'll use a filter then, but ALWAYS? That's pretty extreme. Indoor portrait photographers sure don't need one, as just one example.

To each their own, but with the kind of work I tend to do it's far safer to risk lens flair than it is to risk the lens itself. As I mentioned in a comment above, there are any number of situations where damage to the front element is a distinct possibility. If shooting without a filter works for you, by all means go for it - but it's not a place I'd be comfortable shooting from.