Life is full of compromises. Take lenses: Should you buy the best lens money can buy, or go for a less expensive model? The classic advice is to always buy the best lens you can afford, but what if there is a major difference in price?
Case in point: Leica brand lenses, and indie lenses with M mounts. A high-end Leica lens such as the 28mm f/2 Summicron (right), at around $4,000, costs about as much as an M8 camera, but its sharpness is legendary. And yet, there are lower-priced alternatives, including the budget-priced Leica Elmarit 28mm f/2.8 (left), which runs in the $1,800 range and offers Leica quality...or the downright low-rent Voigtlander Ultron 28mm f/2, which is relatively dirt-cheap at $560.
“Hold on, why are we even having this conversation?” you may be thinking. “These lenses are for Leicas, right? I can’t even afford the camera!” Maybe not--but Cosina has just announced an adapter that converts any Leica mount lens to fit on Micro Four Thirds cameras. And keep in mind, later this year Olympus will introduce a ultracompact Micro Four Thirds camera that, according to one Olympus insider I recently spoke with, will be the digital heir to the classic half-frame Pen-F. Imagine a Leica lens on that camera, or on the Panasonic G-1, and the mind starts to spin with the possibilities.
Now does it make sense to take another look at the image quality of “cheap” M-mount lenses?
How I learned to relax and enjoy my Kobalux
Around nine years ago, I spent $300 on a 28mm f/3.5 Kobalux pancake screwmount lens (left)--plus an M-mount adapter--for my trusty Leica M3. (The lens was sold exclusively by Adorama.) After reading independent test reports, I felt confident that this lens would deliver sharp images at the middle apertures--f/5.6, f/8, and f/11--which were the ones I would most likely use as a street photographer.
The Kobalux is no longer being made because Y.K. Optical Company, a small Yokohama, Japan-based optical company, ceased operations in 2002. Cosina, a company that is very much alive, makes a Color-Skopar 25mm f/4 pancake lens (right) which delivers a 29mm equivalent angle of view on the Leica M8 and at $370 may be the optical heir to the Kobalux.
I still have that Kobalux lens, and had the opportunity to also use the crème de la crème of Leica 28mm lenses, the Summicron 28mm f/2, and decided to live dangerously and run a comparison test of the two lenses, mounted on a Leica M8. (UPDATE: I have since used the Kobalux and a Summicron lens on the Leica M9 and the edge performance is as one would expect: superlative on the Leica, OK on the Summicron). Yes, I know, the corners are cut off by the smaller-than-35mm sensor, but remember that the Micro Four Thirds sensor is even smaller (although there are adaptors that let you use Leica-mount lenses on Micro Four Thirds cameras). I wanted to see how each lens performed at different apertures and show other optical differences. What did I get for $300? What do you get for $4,000? Let’s find out!
David vs. Goliath: The comparison
Size: Since the Kobalux is a “pancake” lens, it is very small, light and unobtrusive. In fact it only sticks out of the camera 2/3 of an inch. Compare this to the larger and heavier Leica lens.
Apertures: But Leica had to make its lens larger and heavier to accommodate the wide f/2 aperture—a setting that’s very desirable in low-light photography. The 28mm f/2 Summicron’s aperture range is f/2-f/16.
Sharpness: To even the playing field just a bit, I shot comparisons of a flat object—the fence in my backyard—using f/3.5, f/8, and f/16, apertures that could be found on each lens. The camera was tripod-mounted and I used the lowest ISO setting, 160.
Did I shoot this with an old $300 lens, or a brand new $4,000 one? If you can’t tell, I ain’t sayin’! (That horizontal wood plank going through the middle of the frame doesn’t demonstrate optical distortion; it’s just warped.)
The difference is in the details, though. Let’s look at 100% enlargements…
At f/3.5, the Kobalux’s focus (left) is clearly inferior to that of the Leica (right).
At f/8, sharpness performance is almost identical. Left: Kobalux. Right: Leica.
At f/16, the Leica (right) lens maintains sharpness better than the Koablux. In fact, as expected, the Leica maintains middle-aperture-quality sharpness (or at least gets really close to it) throughout the aperture range, while the Kobalux’s sharpness falls off at the extreme apertures.
Minimum focus: An obvious difference between the two lenses is focusing distance.
Fairly close: The Leica 28mm f/2 lens can focus to just under 2.5 feet
Where’d the dandelion go? When I put on the Kobalux, I had to back up another foot to get the target in focus.
Flare: Both lenses have coating to reduce flare and ghosting, but neither one can completely eliminate it if you’re shooting straight at a strong light source. Nevertheless, there are important differences.
> Leica 28mm f/2 lens flare stress test: Pointing right at the sun, flare is apparent, with bright blue refractions surrounded by blue fringes. Nevertheless, this is a better performance than the off-brand lens because the image is otherwise not affected. Aspherical elements likely helped.
> Kobalux 28mm f/3.5 flare stress-out: In addition to the similar optical flare and fringing, similar conditions resulted in overall fogginess and reduced contrast.
Other tests showed that the Kobalux exhibited more vignetting than the Leica lens, and there was just a bit of pillow distortion with the Kobalux where none is apparent on the Leica, so on quality, the Leica is clearly the winner, as one would expect.
Is the difference in quality between these two lenses worth an additional $3,500? That depends on you and, honestly, your wallet. For me, the Kobalux is fine: I’m able to make sharp 11x14 prints of photos that I shoot handheld on the streets at ISO 680 (or using Fuji Press 800 film in my Leica M3), and under these variable conditions, I was not able to see any difference between the two lenses. And, I like the lens’s lightness and its small size, which doesn’t call attention to itself when I’m doing candid people photography. But that’s just me.
If your goal is to shoot scenics with lots of detail, high-end portraits and wedding photography, or architecture, or you do a lot of low-light, flashless shooting, the Leica 28mm f/2 may indeed be a very worthwhile investment.