Funleader 18mm f/8 Caplens M-Mount

I’ve always thought of myself as a fun follower, not a fun leader. Well, someone had to try it, right? Two weeks and $179 later, I got a small package from China via City of Industry, California. I almost threw away the lens by mistake. The following will be a brief initial review of yet another interesting lens from China’s burgeoning camera lens industry (another example is the Venus Laowa 15mm f/4.5 shift, reviewed previously).

Funleader is a somewhat obscure company. I actually saw the lens on a targeted Facebook post, making that pervasive surveillance useful to me for the first time ever. The company makes two versions of the Caplens and a drop-in conversion mount to put the 35 Contax G Planar on Leica M bodies. Everything appears to be designed by Mr. Ding (who is the counterpart of Venus’ Mr. Li).

The Funleader 18mm f/8 cap lens / Caplens / whatever is a follow-on to the company’s original 6-element ultrawide-in-a-cap. The difference for Leica M mount is that the lens can actually focus, which is a big deal because f/8 is not quite pan focus for an 18mm lens. The focusing mechanism on the lens is a little lever with a rotating cell. The focusing scale is marked 0.45m, 0.7m, 1m (with a click), 2m, and ∞. This lens is designed for Leica M mount, though in a future installment, I will plug it into a Sony A7r II and a6300 just to see what it does with those.

My assessment of this lens is that it is shockingly not bad. It’s pretty clear that this takes a direct shot at the MS-Optical Perar series of lenses costing five to six times as much (depending on what fetishized finish the Perar features). You’re not expecting the Funleader to compete with a ZM 4/18mm Biogon (which is still five times the price and ten times the thickness…). Let’s do the quick run-through.

Construction. The lens is solid aluminum, decently finished. Mechanical action is nice. All markings are engraved, or at least etched through the anodized finish. This includes the obnoxiously large “FUNLEADER” logo, but a little Sharpie marker will make that less visible. The lens comes with a rear lens cap, but it’s somewhat puzzling that there is no front cap (it would take a 36mm push on, notched for the focus lever). There are no filter threads. The lens weighs 40g, or about 1.3 ounces. It’s not much bigger than a body cap, hence, “cap lens.”

Focus. The lens is not rangefinder-coupled, though the mount will cause the camera rangefinder to read a little over 2m. If you can validate the correct focus-lever position on the lens so that the optical focus matches the RF, you will have at least one place where you can precisely focus. To do this, you need to use LiveView or an EVF. The 1m click stop on the lens is good for moderately close objects. But if you really want to be precise, you will crank it to ∞ outdoors and use an EVF indoors. Or focus-bracket. The Leica M EVFs can easily work with lenses at t/16, so this is no challenge. What might be a challenge is that indoors, you will be on a high-ISO marathon and that focus peaking may require some judgment calls. Fortunately none of those calls are difficult.

Aperture. The iris changes quickly and easily from f/8 to f/8 to f/8 and then back to f/8.

Sharpness. As noted, focus does make a difference, and it seems from looking at prior tests that the original Funleader Caplens (fixed focus) did not have a small enough aperture to cover all distances. Although the caplens is not critically sharp on infinite subjects (like a lot of wides, you are actually best advised to shoot close-to-mid distances), it does have enough bite to work. The following two pictures are scaled down to 3000×2000, but they will go large enough to see that the lens is actually more than passable. In fact, it’s embarrassingly good in some ways (but read on). There is little or no “smearing” at the edges, but where that appears in other Leica-mount lenses, it disappears by about f/8 anyway.

Near (M typ 240):

Far (Monochrom Typ 246)

Casual tests reveal sharpness consistent with at least the 10lp/mm metric shown for the lens if not also 30lp/mm.

Distortion. There is actually vanishingly little distortion at 1m and on. No sample picture is distortion corrected, or even cropped. This is not a symmetrical lens, at least not obviously, but it does have the same straight lines. Distortion is spherical, from the looks of it.

Falloff. Ok, there is tons and tons and tons of falloff on this little guy. Corners are 1-2/3 stops darker than the center. The M typ 240 metadata generator says variously that the exposures are f/8 or f/11 overall. M cameras compare on-sensor exposure with a small photocell eye. The measurement is not perfect, but it can often be very close.

Color shifts (Leica M cameras). This one suffers from the modified bandiera italiana effect, shifting substantially purple on one side and bluish-green on the other. The exact left-right balance seems to depend a bit on the angle between the light source and the lens. The color-shift effect is an artifact of Bayer sensors, complicated sometimes by the microlenses on Leica sensors. You knew that was coming. But it’s an issue on many lenses, particularly symmetrical wide-angle lenses. The “center” can be manipulated slightly by pushing the lens hard from side to side. On some M cameras, there is just enough tolerance to shift the lens on the camera bayonet slightly (the lens flange is slightly smaller than an M body mounting flange).

The color-shift effect should be correctible using Adobe Flat Field. If you even care enough to worry about it.

The Leica Monochrom cameras could care less. They are colorblind anyway. The color shift actually helps darken skies in b/w landscape shots (the picture above was actually taken in bright overcast).

These color shifts should not be as pronounced with film cameras, but film cameras would likely yield poorer sharpness due to the inability to check focus.

Leica M typ 240

Performance on Sony A7R2. Since the optical part of this lens was originally developed for mirrorless cameras, it is not much of a surprise that it performs well with them. Some notes:

• The A7R2 viewfinder is capable of displaying images from f/8 lenses with no problem.
• It is a bit easier to focus with the A7R2 focus peaking than with the M cameras.
• The image stabilization function makes up for the slow maximum aperture. Image stabilization does not fix moving subjects.
• Sharpness is good across the frame. Focus looks correct with a Novoflex ($$$) M to Sony E adapter, and infinity focus may be affected if you use cheaper adapters that are “thinner.”
• Color-shift problems are fairly neglible. Vignetting is still there. The vignetting looks symmetrical, but the color shift makes it look a little lopsided.

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  Spring Blossoms

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  Yes, the fabric blinds are grey, not purple.

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  Try to keep your camera strap out of the quasi-dashcam picture.

Samples from the A7R2 (click to enlarge)

Illumination/color balance on A7R2

Room for improvement. Funleader, if you are reading this, here are a couple of things that would make this lens more fun. These are not critical, but they would improve the user experience a bit.

• A front lens cap, rubber. This lens makes a camera pocketable, so why not protect the glass from the things people carry in their pockets?
• Depth of field marks (this would just need to be two tick marks on the rotating part of the lens).
• 6-bit coding (achievable through simple engraving of the back on the black version).
• An Adobe Lightroom correction profile.
• Wider flange. The lens flange is not quite as wide as an M-camera’s bayonet mount. It would be helpful to have more of a grip surface for mounting/unmounting, since Leica M cameras have very stiff bayonet springs.
• Some way to mount filters – magnetic ring on the front?
• Optional f/16, f/22, and f/64 Waterhouse disks to drop over the lens. When shooting in bright sunlight, it makes sense to stop down. It’s probably not practical to put an iris in a lens this small.

Initial Conclusion. The Caplens is an interesting and creative democratization of the MS-Optical Perar line of lenses, not so fast but a lot cheaper. The performance is surprisingly good, especially given the number of pans of the prior version in reviews. It’s not a 4/18mm ZM Distagon, and in color, it has some Lomo-ish (or 4,5/21 ZM Biogon) characteristics, but all in all, it’s a very nice lens for the money.