The above video is a shortened version of this entry.
Cosina are a Japanese lens manufacturer who produce lenses under their own and under companies names. In 1999 they leased the licensing of the Voigtländer name and started making camera bodies and lenses. Sadly they have stopped making cameras but are still making lenses in the following mounts:
VM – or Leica M
Sony E Mount or Nex
There is no need to worry about Cosina’s ability to manufacturer lenses as Carl Zeiss has them make many of their lenses.
This article is about the 35/2.5 P type II VM mount MC version. Which is a way of saying that there have been several versions of this lens with different mounts and lens coatings and this model was introduced in February 2004, I purchased it new that year, and it is still in production. Physically the lens is similar in styling to the Leica pe-aspheric 35mm f2 Sumicron right down to the inclusion of the finger tab on the focusing ring. The vented lens hood is an optional but essential extra, so if purchasing new budget for it, if buying second-hand look for a copy with it included. Readers not familiar with range finders may scoff at the design of the lens hood but the design was necessary so that the hood would not obstruct the view through the viewfinder. Not necessary when adapting the lens to the Sony A7 cameras but it does make the lens look cooler. Yes my copy has a dented lens hood, the lens has been very well used over the years. It also shows that a lens hood provides more protection against damage than a filter ever could.
Lens Vital Statistics
The construction is all metal and for such a tiny lens it has a reasonable heft and feels very dense. So as you can see this is truly a “pancake” lens and makes a very nice all day walk around pairing with a Sony A7. Street and landscape photographers rejoice! The lens also has marked on its barrel along with the focusing scale depth of field markings, this makes zone focusing and setting the hyperfocal distance a breeze. Set at an aperture of f22 everything from 1 metre to infinity will be in focus. The focusing ring has a smooth throw of around 90º coupled with the afore-mentioned finger tab and focusing while the camera is at eye level is just so easy. The aperture ring while admittedly very thin has two tabs on it opposite each other that help you find the ring by touch and adjust without taking your eye from the viewfinder. So while it would be easy to dismiss the lens because of its retro styling these little inclusions show that this is a lens that is meant to be used. To use it on anything other than an M mount camera you will need an adapter.
Mounted to my Sony A7r how does it perform? Unsurprisingly for a pancake lens vignetting is quite apparent wide open at f2.5 along with a magenta colour cast along the edges and in the corners of the frame. The vignetting is a result of the optical design, the magenta cast the result of putting a true 35mm lens in front of a digital sensor designed to use retro-focused lens designs. The lens was designed for film so it didn’t matter that the rear element was so close to the film plane as the silver halide crystals in the emulsion didn’t care whether the light rays were hitting them perpendicularly or not. Digital sensors do require the light rays to hit perpendicular to the sensor plane, if they don’t you get light fall off, smearing and colour fringing. The Sony A7 cameras because they are mirrorless designs have micro lenses on the sensor that help pick up the light rays at acute angles, but the camera needs to know what the lens is before any correction can be applied. This lens has no electronic communication with the camera so the cast remains. The performance of the lens improves considerably as the lens is stopped down, so the vignetting is all but gone by f8 but the magenta fringing continues throughout the aperture range. Happily the colour cast can be removed in post. If you use Adobe Lightroom there are correction profiles for the Voigtländer lenses – the video accompanying this article shows how they work. If you use other processing software have a look at Cornerfix which is a little app that allows you to build lens profiles.
When it comes to distortion – there is some barrel distortion, but that is easily fixed in post as is the small amount of chromatic aberration. Sharpness at f2.5 in the centre of the images is very good with nice edge contrast befitting a modern multi-coated lens. The edges are considerably softer with less contrast. The wide angled rangefinder lens in front of a digital sensor problem comes into play here. A lot of people will complain that there is smearing of detail, and that is true it does happen (Spoiler Alert!) and wait until you see my review of the CV 15mm f4.5 as that has it in spades, but with this moderate wide-angle and it’s fairly sedate maximum aperture of f2.5 the light rays are not being forced to hit the sensor at extreme angles so there is no visible evidence of detail smearing in the corners of an image. Like most lenses used on a 35mm sensor diffraction sets in at f16, it’s not disastrous. Diffraction is not like falling off of a cliff – at f11 everything is sharp then at f16 everything is out of focus. No there is a slight loss of edge definition which is a little more noticeable at f22. Flare is well controlled, but I would still recommend the lens hood and the 10 aperture blades produce nice sun stars.
Well lets look at pricing first. B&H Photo sell this puppy new for just over $400 USD sans lens hood at the time of writing. There are dealers on eBay that sell them for $350 USD and second-hand copies can be found starting at just over the $200 USD mark. This is not a sexy fast aperture lens and the price reflects that. There are only 7 lens elements with no fancy shapes. What you are getting is very compact moderately wide angled lens with a modest maximum aperture of f2.5. It is well designed and for stills photography is a delight to use. For video it is possible to use it, but the focus throw is a little on the short side, the small size makes operating the lens a little harder while filming and the small filter size makes the use of variable neutral density filters a little cumbersome. It is not a lens that lens snobs would consider, but it is a very fine workman like tool that I won’t ever sell because it is well made, functions well and is optically very consistent. If you like manual lenses and see one at a good price buy one. Like the many people who left reviews on the B&H web page you won’t be disappointed.