Kobalux Wide 28mm F/3.5 LTM Lens Review

1800 1012 James Tocchio

The Kobalux Wide 28mm F/3.5 LTM lens is an uncommon and uncommonly tiny Japanese lens that harkens back to old-world quality. When a fine example of the lens came through the shop on consignment last month, I knew I had to shoot it before listing it for sale. And I’m glad I did. It’s an interesting lens with an intriguing history, the sort of lens that Casual Photophile was made to explore. And for photographers searching for a tiny, collectible LTM lens with solid performance at a reasonable price, it’s an attractive option.

What is Kobalux?

The history of the Kobalux lens isn’t exactly murky. But neither is it crystal clear. Let’s start with the known facts; Kobalux is one of a number of brand names for two different lenses made by a Japanese micro-manufacturer known as Y.K. Optical, based out of Yokohama. These two lenses, a 28mm and 21mm for Leica Thread Mount (and M mount through the use of an adapter) were sold in the United States under the trademark Kobalux, and in Japan under the brand name Avenon. For many years the lenses were imported by Adorama and offered for sale in their shop. That’s what I know. The rest of what’s said about Kobalux online can’t be verified (yet – I’m working on it), and so it falls into the class of information that’s really just echoed speculation.

The internet says that Y.K. Optical was founded by a person named Mr. Abe, who is said to have been the lead lens designer at Japanese optical company Sankyō Kōki K.K., which manufactured Komura brand lenses and went out of business in 1980. So, the story goes, Mr. Abe left Sankyō Kōki K.K. when that company became insolvent in 1980. He then designed and produced the two Kobalux lenses. I’m sure that there’s someone out there who knows this history perfectly well, someone who negotiated the import deal and had tea with this Mr. Abe (Dante Stella, are you there?). If that’s you, let me know. But from where I sit, I can’t find enough information to satisfy my curiosity.

Working backward through history, we can see that Mr. Abe’s Y.K. Optical ceased operations in February, 2002. This is known from the archived Kobalux website – no longer live. On this archived site, Y.K. Optical calls their Kobalux production period a “successful seven-year run[…]” indicating that the brand was manufacturing Kobalux lenses only since 1995. But Kobalux lenses are supposed to have appeared prior to this, apparently as far back as 1982. This date does align with Abe’s reported departure from Sankyō Kōki K.K. But who was making Kobalux lenses between the years 1982 and 1995, if not Abe’s company Y.K. Optical? Some sources say that the original lenses were made by a company called “Avenon Optical.” Was this also Abe’s company?

Another wrinkle in the narrative – remember those brand names? Kobalux in North America; Avenon in Japan. Well, a search of the United States Patent and Trademark Office database returns exactly zero registered marks for Kobalux or Avenon, live or dead! So we’re unable to really trace who was making these lenses, where, and who owned the company. Reaching out to the last known email address of Kobalux returns an undeliverable mail response – the Kobalux domain is long dead.

Did the mysterious Mr. Abe really design the Kobalux lens, but sell the design to be produced by another company (perhaps the mentioned “Avenon Optical”) from 1981 to 1995? Or was it another mystery company? Was Abe the owner of both companies, and did he simply change the name of his company to Y.K. Optical in 1995, leaving the first company name lost to history? Is it possible that Abe had nothing to do with the design of this lens, and did he and his Y.K. Optical company simply purchase the existing manufacturer of Kobalux lenses in the mid-’90s? Does Abe-san even exist? Who is Mr. Abe?

I can’t answer these questions. And to be fair, answering them isn’t exactly critical. But it’s satisfying to know stuff, and not knowing stuff is frustrating. It’s also sort of my job to know this particular kind of stuff.

My usual reference materials have failed to mention Kobalux in a significant way prior to 1996, or a Kobalux-connected Mr. Abe in any way. I’m not saying that the information repeated on the internet isn’t true, but the paucity of verified fact from a reputable editor-backed photo magazine of the period is leaving this journalism minor squirming. Someone’s got to fly to Yokohama and start knocking on doors. Or dig up the guy or gal who struck the import deal at Adorama. Until that happens, the history of Kobalux isn’t gelled.

One thing about Kobalux that I know for certain is that the lens exists. I’m holding it right now. It’s definitely real. Let’s cling to that.

What is the Kobalux Wide 28mm F/3.5?

The Kobalux Wide 28mm F/3.5 is a Leica Thread Mount wide angle lens, made in the classic Japanese style – all metal, simple, compact. In fact, according to Kobalux’s archived site, the 28mm F/3.5 was the smallest 28mm LTM lens ever made as of 1996. If this isn’t true, it’s close. The Kobalux is indeed tiny.

The Kobalux Wide 28mm F/3.5 LTM used an optical formula made of six elements in four groups. The later version, made from 1995 on, is multi-coated, and has eight aperture blades. Earlier lenses, like the one I’m shooting, are single-coated and with just six aperture blades. Image quality from the two different examples is largely the same, with the later model offering slightly improved flare resistance. The lenses are rangefinder coupled, focusing from infinity to 1 meter, with a focusing tab (round in earlier lenses, crescent-shaped in later units) that rotates approximately 85º from one extreme to the other. There’s an infrared focusing mark, and a distance scale corresponding to depth-of-field scale for scale or zone focusing.

The lens is well-made and impressive, like many classic Japanese rangefinder lenses. An all-metal body is adorned with finely engraved numerals and precision knurling of the aperture ring, which is thin and clicks mechanically into its single-stop detents with a light touch. Later lenses had half-stop detents. The focusing action is smooth and precise, and very fast owing to the short throw. In many ways it feels reminiscent of the fine M Rokkor lenses made by the much larger Minolta company, a compliment to Kobalux’s manufacturing.

Simply put, the Kobalux Wide 28mm is a classic, beautiful rangefinder lens made in an era of plastic. A throwback to quality. It doesn’t feel as solid or robust as a Leica lens, but then again, Leica never made a 28mm this small or this inexpensive.

Photo by Maazin Kamal, used with permission.

Image Quality and Sample Shots

Image quality from the Kobalux Wide 28mm F/3.5 is pretty impressive, with some caveats. Center sharpness is great at all apertures, even wide open. Corner sharpness at F/3.5 suffers, as we’d expect. But compared to old Leica LTM 28mm lenses, the Kobalux performs well in this regard. Even compared to later-developed 28mm LTM lenses, like the Voigtlander 28mm F/3.5 Color Skopar from 2002, the Kobalux is a comparable performer (and the Kobalux is smaller, too). As we stop down the aperture, the corners sharpen up as we’d expect. By F/8 we’re seeing uniform sharpness across the frame. Standard stuff, but impressive from what was by all measures a small manufacturer.

Vignetting is pretty heavy, and what’s surprising is that this vignetting doesn’t improve as drastically as it does with other wide angle lenses I’ve used. Even at F/5.6 we’re still seeing significant vignetting. At F/8 there’s still vignetting! It’s pretty wild. Vignetting can be helped away in digital post-processing, or used to accentuate a subject, so I don’t see this being the most egregious offense that a lens can make. But it’s worth noting.

Photo by Maazin Kamal, used with permission.

Photo by Maazin Kamal, used with permission.

Flares, even in my single-coated early version, are well-handled. Shooting directly into the sun will create flares. But there are few lenses made which can claim otherwise. Photographers who are bothered by flares should use a screw in lens hood, or avoid pointing the glass at the overbearing and enormous sphere of hot plasma that greedily accounts for 99.86% of the total mass of our solar system. I guess I shouldn’t complain. The Sun was here 4.6 billion years before the Kobalux.

Bokeh doesn’t really impress, but there are few 28mm lenses with impressive bokeh. Highlight bokeh looks okay, and it’s possible to get nice subject isolation when shooting at the lens’ minimum focus distance. But really, the 28mm lens is made for contextual photography. Landscapes, street photography, portraits in which the background is as important as the subject – this is where the 28mm lens works, and this is no different with the Kobalux. Set it at F/8 and, as the old adage goes, be there. Shot in this way, the Kobalux Wide 28mm F/3.5 leaves little to be desired.

[More digital sample shots will be added to this post in the next 24 hours, dear reader. Check back tomorrow if that’s helpful for you. For now – Deadlines!]

Final Thoughts

An uncommon, finely made Japanese LTM lens at a relatively low cost? The Kobalux Wide is all of that. In its own time it was a strong value proposition, and today, when digital mirrorless cameras can easily adapt any lens made in the last eighty years, its value remains. While there are cheaper options available from other Japanese brands, Canon for example, these lack the Kobalux’s rarity. For anyone seeking a bit of photographic history, a bit of an oddball with character, and a decent deal on a high performer for their LTM mount film or digital mirrorless camera, it’s smart to consider the Kobalux Wide 28mm F/3.5.

Get your Kobalux Wide 28mm lens from eBay here

Shop for lenses at our own F Stop Cameras

Follow Casual Photophile on Facebook and Instagram

[Some of the links in this article will direct users to our affiliates at B&H Photo, Amazon, and eBay. By purchasing anything using these links, Casual Photophile may receive a small commission at no additional charge to you. This helps Casual Photophile produce the content we produce. Many thanks for your support.]

James Tocchio

James Tocchio is a writer and photographer, and the founder of Casual Photophile. He’s spent years researching, collecting, and shooting classic and collectible cameras. In addition to his work here, he’s also the founder of the online camera shop Fstopcameras.com.

All stories by:James Tocchio
  • Wilson Laidlaw July 1, 2020 at 2:46 am

    I wonder if they might have been manufactured by Kirin for Kobalux/Avenon. Kirin seem to be a very shy and retiring company, making lenses on the quiet for various companies, such as Zeiss and Rollei and accessories for many such as filters and lens adapter but never marking their products with their name. On older lenses, the use of a particularly glossy deep and hard black enamel is one identifying feature for Kirin lenses. Much of their current output is lenses for mobile phone cameras, for the likes of Huawei.


    • I would love to know the definitive history of the brand. Some people have said that the end of production coincided with the owner of Y.K. Optical’s death in 2002, but I could not corroborate this. Contact information for the Kobalux brand and Y.K. Optical failed to deliver. Reaching out to Adorama yielded no information. I’m not sure if the person who imported these lenses in the 1990s has moved on (Adorama placed their final order for Kobalux lenses in 1999). I also reached out to another U.S.A.-based importer, but did not receive an answer. It’s possible that the people originally connected with this brand and the selling of the lenses worldwide are just out of the game. Lost interest, or passed away, or can’t be bothered with ensuring that the world remembers Kobalux lenses. This happens sometimes. I’ll keep looking.

  • Well thank you very much, James, you’ve just made me put a big dent into my bank balance! Here I was enjoying a morning cuppa and whilst nonchalantly browsing my inbox up pops your review. A brand I’d never heard of and a focal length I’ve no use of, as at 28mm I get excellent results from my slower f6 Russian Orion-15 in LTM mount (I have the Contax RF version, too) and which performs admirably on my Sony A7 with edge to edge sharpness. So I have no need of this lens.

    However, intrigued, I checked out ebay UK and up popped just two, and not cheap. Then I decided to search for Avenon, and this is how my bank balance became depleted because that’s where I saw listings for a 21mm lens, a far more interesting proposition for me, as in LTM I go from 28mm to 15mm (CV Heliar) and nothing inbetween. One listing stood out as it included the necessary 21mm finder, all caps, lenshood, soft pouch case, manual, and box. Described as mint, and from the high quality images posted, this looks accurate, and with no optical issues at all. Oddly, the price was around the same as the two Kobalux branded 28’s. Perhaps there is a different collector appeal for the Kobalux because the lens is rarer?

    Perhaps asking for top jolly performance from an f2.8/21mm RF lens will be too much, but it is certainly something a little unusual.

    Thanks for the review, despite my (tongue in cheek opening comment) and providing what little info there seems to be out there about Kobalux aka Avenon.

    • Good purchase! I’d love to try the 21mm. My 21mm Super Angulon in Leica R mount is my favorite lens, and it’d be fun to compare. Let me know how yours goes!

  • It would be interesting to see how this is on digital. I reviewed voigtlander’s tiny 35mm f/2.5 Vm lens a while back and while there was minimal vignetting on film – on digital it existed throughout the entire aperture range. What a fun lens though!

    • It’s exactly the same here. You can see it in the vignette samples, which were made on digital. The digital sensor picks up a lot more vignetting and there’s some color shift as well. This varies by sensor, but on my Sony a7II and the Leica M10 it’s pretty noticeable. I’ll be adding some more digital sample shots to the article this week.

  • First off, I love the top two product shots of your daughter holding the lens. High key with soft colours. How did you do that (and with what?)?

    This lens a couple o years ago was cheap. $200 mark. Now it is more expensive than the CV 28 3.5, which honestly is a really tough sell. The CV lens is really really nice…

    Best regards

    • Yeah, it’s pricey for sure compared with that and some of the equivalent Canon LTM lenses. But it’s cheaper than the Leica lenses. Maybe rarity or just greater knowledge has contributed to the increase in prices. And it is, after all, possibly the smallest 28mm lens you can buy for LTM. But anyway…

      I shot the product shots with my daughter pretty simply – a Sony a7II with the Sony 50mm f/1.8, some processing in Lightroom like always. Up the exposure by 1, up the shadows by about 0.5, some color correction to taste. I’m sure my digital edits aren’t to everyone’s taste, but what can ya do?

  • That was an enjoyable read and I like your sample photos. I have this lens too. Mine is the single coated Avenon version in black. It’s really incredible how tiny this thing is when mounted. I don’t use mine that much (only because I’m pretty useless with a 28mm), but when I do I mount it on my Minolta CLE. It’s a great combination because the CLE is tiny itself, but has big 28mm frame lines.

    Third party Leica mount lenses are often fascinating because they frequently seem to be rare, be odd focal lengths, or come from a weirdly limited range (e.g. Y.K. Optical’s 28mm and 21mm, Pentax’s one or two Leica lenses, Olympus’ I think just one lens, Kodak’s 47mm Ektar too). Consequently, they’re often expensive to pick up, and one often has no idea whether this actually reflects their quality, or just their rarity.

    On the other hand you have Cosina Voigtlander, and I sometimes think, why on earth do they produce such a wide range of different 35mm and 50mm lenses? And yet, CV haven’t produced their compact 28/3.5 lens for years and years. Surely it would be very popular if they re-launched it?

  • I want to know if it is incompatible with Canon VL. I saw yours can be mounted but I heard that it’s not compatible with Canon P and Canon 7.

    • Axel, as it is an LTM thread I’d be very surprised indeed if it was incompatible with a Canon 7. I’ve used a range of LTM lenses on my Canon 7 from the 15mm CV Heliar and longer, and including the much larger 21mm Kobalux. Whilst not a compatibility issue, per se, with the Canon 7, the combination of any lens wider than 35mm does pose an issue in handling as the camera’s widest frame is 35mm and it doesn’y come with an accessory shoe to mount an external viewfinder, as the later 7S does. Canon did supply a small accessory flash bracket which does include a cold shoe, but these are quite difficult to come by now. Other than this potential handling issue I don’t understand why people would say the 28mm is incompatible with the Canon 7.

    • This is interesting that you brought this up, Axel. I came across this statement from the kobalux website (not sure if it’s the official one or not):

      “When mounted on a camera, the lens protrudes deeply into the camera body. Because of this, it cannot be mounted on some cameras, notably on Canon series V cameras, Canon series VI cameras (Canon P, etc.), and Canon 7. On these late Canon Leica Screw Mount bodies the lens would hit the camera’s internal light shield.”

      Yet I see that James’ review had the 28mm Kobalux affixed on the Canon P.

      Here’s a case of User Manual vs User Experience – User Manual implies I could ditch my ambitions to get a Canon 7sz, while User Experience seems to imply that I could possibly get 2 rather rarities together (the Canon 7Sz + 28mm Kobalux).

      So…. does it work with the late Canon rangefinders… does the lens protrude into potentially damaging space?

  • it’s better than some new things…made from recycling, I am agree for recycling old lens, but made and created totally by true people 😉

Leave a Reply

James Tocchio

James Tocchio is a writer and photographer, and the founder of Casual Photophile. He’s spent years researching, collecting, and shooting classic and collectible cameras. In addition to his work here, he’s also the founder of the online camera shop Fstopcameras.com.

All stories by:James Tocchio