First of all a disclaimer. Despite this being the second Sainsonic lens review on this blog, I am in no way affiliated with Sainsonic and have purchased both the 21 and the 28mm. I have previously won the Kamlan 50/1.1 Mk I in a giveaway, but frankly, it is not my cup of tea, so I do not feel swayed one way or another to the company.

I used to use and love Pentax cameras and they made an awesome pancake Pentax-DA 21 mm f/3.2 Limited. Granted, the max aperture was nothing to write home about, the corners could have been better and perhaps the distortion was a bit too pronounced for some, but the images it produced were magical to me and it was my absolutely favourite walkaround lens. Ever since switching to Fuji, I found myself missing this focal length. Yes, Fuji makes two awesome 23mm lenses, but the f/1.4 is a bit too large and the f/2.0 didn’t really entice me. Fast forward to the Chinese manufacturers emerging: The 7Artisans 25/1.8 was a fun toy effect lens and I would recommend it to anyone for the price/fun factor ratio. Then I had a brief affair with Zonlai 22mm f/1.8, which I might review as well, but as you can already guess, I didn’t become a fan. 

Having used the Kamlan 28 mm f/1.4 for some time now and liking it to the extent that it became my default walkaround lens, I was thrilled to find out that Sainsonic is preparing a 21mm f/1.8. It was surprising there was no Kickstarter campaign, as there was for the 28mm and until recently ongoing 50mm f/1.1 Mk II. In fact, they released the 21mm with no fanfare, zero advertising. If it wasn’t for Fujirumors, I wouldn’t have known it was released at all. Didn’t they want the 21 stealing the limelight of the 50/1.1 Mk II Kickstarter? Or do they know it’s going to be a treasure and the word of mouth is enough to make this one sell? Let us see. All pictures are jpgs straight from Fujifilm X-T20, Sharpness -2, Highlights -1, Shadows -1, other values default.

Build quality

If you have owned any Kamlan lens, you can skip this part. It is essentially the same good build quality of metal and glass, with the only plastic part being the bayonet lens hood (which is interchangeable with the 50mm f/1.1 Mk I and 28mm f/1.4). The focusing ring is nicely damp and smooth. The aperture ring is declicked (as all the Kamlan lenses to date) and unlike the 28mm I own, is not as stiff.  That being said, I would still prefer a clicking aperture ring (or declickable option). One thing nobody mentions: Kamlan makes the best Fuji rear lens caps. Period. They are smaller than any other ones, while locking securely and protecting the rear element snuggly. No accidental falling off the cap ever.
With regards to dimensions, the lens is quite small. Not a pancake, but definitely smaller than the 28mm and even slightly smaller than the 50 mm Mk. I, which is a good achievement. Weighing only 264 gm the lens sits nicely balanced on my Fuji X-T20. The aperture count stops at 11 blades, which make a nice circle and should add to the bokeh being nice and smooth. However, I couldn’t coerce the lens to produce any decent starbursts

The lens is fully manual with no electrical connection to the body. Make sure you enable the appropriate mode on your camera, so you can use it. 

Image quality

Sharpness

If I had to sum up - really good, similar in its character to the 28mm f/1.4. The center is sharp already wide open, giving a nice shimmer in the viewfinder even without focus peaking, making the manual focusing easy. Wide open the corners are somewhat softer, which is to be expected, but there is a good improvement at f/2.8 and f/4. At f/5.6 the sharpness is really good across the frame, with only the extreme corners not being the same sharpness, but still good. At f/8 the resolution is really even. The good thing is, that even at wider apertures, the wider center of the image has good sharpness, so you can put your subject within the rule of thirds without fear of losing  much resolution.

Many modern wideangles suffer from a midfield resolution dip caused by the lens optical construction. The Kamlan 21 has it to only a tiny degree and I had to go looking for it. The lens rivals the Kamlan 28mm and I have a feeling the uniform resolution at f/5.6 even surpasses it in the corners, which is a great success, given that designing a wider lens is always more challenging. Sharpness-wise, it is definitely useable for landscapes.

Colors are rich, but not oversaturated and contrast after f/2.8 leaves nothing to be desired.

To give you an idea, as to how the sharpness improves, have a few 100% crop comparisons showing the improvement between f/1.8 and f/4.

Vignetting

As expected with the large aperture wide angle, there is some vignetting at wider apertures, which is visible wide open, but not disturbing and easily correctable. By f/4 the illumination evens out considerably and at f/5.6 even a pixel peeper would have trouble spotting it.

Distortion

There is visible distortion when shooting at shorter distances, but it looks easily corrigible in PP. When shooting near infinity, I was hard pressed to see any distortion, but your mileage may vary. Overall, I do not think distortion is a big issue with this lens. 

Aberrations

Shooting around infinity, wide open and in high contrast situation, you will get some minor purple or blue fringing at the edges of objects, which are not in focus, but it is really really minor. By f/2.4 the aberrations clean up nicely. Wide open and focusing close, the depth of field is rather thin, so the out of focus fringing is visible when zooming in, but in really contrasty areas, the purple fringing only clears up around f/4. One big plus is, that the lens is really well corrected across the frame. I gave the lens a real stress test with big milky glass window in the frame. In the corner and under such extreme contrast, the purple fringing never went away even at f/5.6, but there are not many lenses, which could do better and it is still easily corrigible. Compared to Kamlan 28, there is also a good correction to coma, which doesn’t show at all, compared to the aforementioned lens.

Flaring

Flaring is present, especially if the light source is in the picture frame, but again, it is quite well controlled. While you do get some lens flare effects sometimes, the veiling flare is almost nonexistent and may I add, the Kamlan 21 represents a big step forward from Kamlan 28 in terms of flare resistance. Lens hood is definitely recommended at all times.

Close focus

The Kamlan 21mm focuses as close as 12 cm, giving it a respectable magnification of 1:3.4. As someone who likes to get close to my objects, I appreciate that a lot. The center resolution holds up really well even when close focusing, so I can only recommend this lens for it. 

Bokeh 

As I said before, the 11 circular blades should make for rather good bokeh, but how is it really? Smooth out of focus areas have not been a priority with wideangles in the past, but given the big maximum aperture and close focusing capabilities, bokeh should be one of the priorities. Long story short, bokeh is quite smooth even stopped down. Really no complaint from my part, you can see a few examples below.

Compared to Zonlai 22mm f/1.8

As the Zonlai is probably the closest lens to Kamlan in terms of focal length and price (around 150 USD for the Zonlai), I decided to show you a few comparative shots from both lenses. As you can see, the Kamlan has greater resolution already wide open in the center. The corners are a whole different league at any aperture. As other reviews mentioned, the Zonlai can come with decentering issues, and I admit, I bought two copies, but not even the second one can really hold a candle to Kamlan.

Verdict

So, what’s not to like? Kamlan 21 is a focal length I’ve been fond of for a long time. With really good sharpness across the frame, good close focusing abilities and remarkable aberration correction, this lens can be a very versatile workhorse for all genres, including landscapes and street. At 179 USD, it is an absolute bargain, if you don’t mind manual focus. Any alternative is simply worse or much more expensive.