Zonlai 25mm f/1.8 is a cheap Chinese manual focus lens for APS-C mirrorless cameras. You can buy it on eBay or elsewhere for around $100 under a variety of brand names — Zonlai, Discover, Kenro, Hengyijia and maybe others.
I actually own two copies — Discover and Hengyijia for Fuji X mount and they are exactly the same design. This review will cover mainly Discover lens as that’s the one I used the most. As far as I can see, the lenses differ only in their defects, which are covered below.
One important thing to note is that as far as I know there are two versions of this lens. They are easy to distinguish, first generation has unusual placement of aperture and focusing ring — focusing ring is close to the camera body and the aperture ring is near the front lens element. Second generation has traditional ring placement — aperture ring close to body, focusing ring close to front of the lens.
This is a small all-metal lens which feels very solid in hand.
I think it fits well design-wise with the Fuji aesthetics. With my Fuji XT-10 it forms a small and well balanced combo.
Handling and build quality
Focusing ring is well dampened on the Discover lens. Focus throw is quite short (about one third of lens circumference) which makes manual focusing a bit challenging with larger apertures. On Hengyijia, dampening is a little bit looser which makes accidental misfocusing more frequent — sometimes I focused correctly, shot a picture and then at home I found out it’s far from focused correctly. I think that in the second between focusing and activating shutter I must have slightly altered the focus which in combination with very short focusing throw made a big difference in the photo sharpness.
With all that said, manual focusing is quite enjoyable. As I understand this is a big difference compared to the first generation where the focusing ring placement made manual focusing awkward.
Focusing ring has a distance scale to aid in zone focusing. But focusing is probably misaligned in some way and the distance scale is off — infinity is around 6 meters mark on the distance scale. Anything after that focuses “after infinity” — i.e. nothing is in focus.
This probably differs one copy from another — in my case Discover is slightly more off than Hengyijia.
Aperture ring is click-less and goes from f/1.8 to f/16. On Discover copy, it is well dampened (similar to the focusing ring) which makes it nice to use and makes it unlikely to be changed by mistake.
Aperture ring on Hengyijia is a little bit worse — from f/2 to f/8 it’s a little looser and from f/1.8 to f/2 and f/8 to f/16 it’s tighter and you need a bit more force. It also feels like there is some dust particles in the mechanism which makes the change not totally smooth as in the Discover copy. But these “defects” don’t present any real problem in use.
I noticed that aperture ring is quite off. I did a very simple non-scientific test — I set the camera on ISO 200, lens on f/2 and tuned the exposition compensation so that shutter speed falls on 1/100s. Then I switched lens to f/4, f/8 and f/16 to see what’s the shutter speed, expecting that it should go down by the factor of 4 (since I’m testing 2 stop differences). Results (sorry for the table look):
| Aperture | f/2 | f/4 | f/8 | f/16 |
| Measured shutter speed | 1/100 | 1/58 | 1/25 | 1/8 |
| Expected shutter speed | 1/100 | 1/25 | 1/6 | 1/1.5 |
One possible explanation is the heavy vignetting at larger apertures which makes metering choose slower shutter speed than expected.
The only remark here is that front lens element on the Discover copy has small bubble roughly in its center. It doesn’t seem to affect the image in any way.
I wondered for some time if it could be some optical effect and not real bubble. But since Hengyijia copy arrived and it has nothing like that, it must be real.
Lens hood is part of the package. It’s metal and looks and feels very nice — reminds me metal hood from my Fuji X100. It screws into the lens without locking.
Lens mount is the same metal as the rest of the lens. Feels solid. It has white dot which helps with orientating the lens before mounting.
This section is actually quite lens-agnostic, but I’ll mention it anyway since it’s essentially my first “normal” manual lens.
This lens is fully manual — there’s no auto focus (and no electronics) in this lens. Because there’s no electronic connection between camera and the lens, camera can’t actually detect that lens has been placed into the mount. To be able to shoot pictures with fully manual lens, you need to configure your Fuji camera to “shoot without lens” in the menu.
If you switch focus lever on the front of the camera to “M” position, the manual focus assist is activated. I use focus peaking with highlight or “standard” focus peaking (zooming) without any highlighting and still can’t decide which one is better. Highlighting sometimes highlights things mistakenly and obscures the detail, but then I make mistakes without the highlighting as well. Third option “digital split image” wasn’t very useful for me. You can cycle between these modes by long pressing the rear wheel.
Short pressing the rear wheel zooms into the center of the picture to fine tune the focus — this is one single most important feature for precise manual focusing.
Sometimes manual focusing is more difficult though:
- shooting with wide aperture (e.g. f/1.8) — depth of field is very shallow and slightest movement of focusing ring can put the subject out of focus. In such cases I sometimes move slightly the camera front or back instead of focusing ring for easier fine tuning.
- when shooting in low light, viewfinder is usually quite noisy and it’s difficult to see what is in focus and what isn’t. The main problem here is that focus peaking highlight looks quite similar to the noise in the viewfinder. To mitigate this, you can set the highlight to red color. Also in low light you typically use wide aperture which makes it even more difficult.
- in extremely sunny weather it seems to be sometimes difficult to see what’s in focus and what’s not. I had this problem particularly on snow — snow produced a lot of highlights in the viewfinder which is again similar to focus peaking highlights. I mis-focused several images because of this. Split image manual focus assist might be better in this use case.
One note to the camera — viewfinder of my XT-10 is relatively small which is not ideal for manual focus. Having XT-1/XT-2 with their much larger viewfinder would probably make the experience better with more images in focus.
This is not macro lens, but it has better macro (closer focusing) than my other lenses (Fuji 18–55m f/2.8–4, 55–230mm, 35mm f/2).
Center sharpness looks pretty good to me —of course not to the level of Fuji primes. Corner sharpness is quite bad, especially in larger apertures where corners are very mushy.
Wide open the lens vignettes pretty heavily, of course it gets better as you stop it down. I’m fine with that, I mostly like vignetting and sometimes add it to my pictures during post processing anyway.
Zonlai is clearly making image quality compromises to keep the size, weight and price down while being pretty fast. For me this is a “fun” lens so I embrace the compromises and love the benefits of size and speed.
Color reproduction is definitely different than what I get from my Fuji lenses. Fuji lenses are known for their colors, but even good things get old after a while so I like the different look this lens provides.
Most of the pictures on the page are shot with Discover copy, shots of the Discover lens are from Hengyijia and pictures of camera + lens is from my smartphone.
For me this is great work-around, non-serious lens for situations where I’m not under time pressure and can work slowly and intently. I love the compactness, balance on the camera and different feel to the images compared to the Fuji lenses. Its 25mm focal length (~38mm full frame equivalent) is pretty universal — it’s usable as both wide angle and environmental portrait lens.