Mirrorless system lens compatibility recommendations

For those of you with legacy system lenses, compact system cameras seem to make sense, yes? You can use all of your old lenses on newer bodies via adaptors and you’ll not only get to use your favorite optics, but you’ll save money to boot. And the really short back flange distances of some of the lenses mean that just about everything from an SLR or RF mount will fit with the right adaptor.

Well, not quite: firstly, all the fields of view will be different unless you’re going between APSC and APSC. Then there’s also the issue of size: why buy a compact mirrorless systems with the intention of reducing weight when you then go stick an enormous lens on the front?

Bottom line: there are many disadvantages to using legacy glass on mirrorless systems; more so than advantages. I knew that going in, and only use my micro four thirds system with dedicated lenses; but I have got a whole drawer full of adaptors, mostly purchased out of sheer curiosity.

If you are hell bent on making unholy pairings, then read on.

Quick aside: ‘Good’ means lenses work well, and deliver excellent or outstanding optical results; better than the system’s native lenses. ‘OK’ means that they work about as well. ‘Bad’ means that you shouldn’t bother; most of the time this is due to non-telecentric wide angles not playing nice at the edges due to very short back flange distances and a lack of offset micro lenses on the sensor to counter sharp angles of incidence between image rays and sensor. This manifests as purple fringing, chromatic aberration, vignetting, and corner softness. It could also mean the lens just doesn’t have enough resolution to deal with a very high density sensor – for instance the 24MP Sony NEX-7. There are exceptions to this rule, and where I’ve found them, I’ve noted them. The Ricoh GXR M-module is an exception because it does have offset micro lenses and was specifically designed for RF glass.

Sony NEX
Good: Legacy Sony/ Minolta telephotos and normals; new Sony midrange and high end zooms; Leica M telephotos
OK: New Sony wides; Leica M normals
Bad: Older wides; Leica M wides; C-mount/ CCTV lenses (won’t even cover the image circle!)

Micro Four Thirds
Good: SLR high end telephotos, SLR normals, RF telephotos. Exception: Zeiss ZF/ZF.2 glass, Leica 35/1.4 ASPH FLE.
OK: SLR midrange telephotos; some of the slower RF normals
Bad: Leica M wides (pay attention to your adaptor: cheaper ones probably won’t be planar, and land up causing obvious astigmatism. They may not even focus to infinity, or minimum distance!). The Leica Noctilux 0.95 does not do well on micro four thirds; it displays a lot of CA and blooming. I suspect that it is only optimized with the focal plane precisely at 28mm from the flange. Most C-mount/ CCTV lenses – these lack the resolving power and flatness of field.

Nikon 1
Good: Any of the new Nikon lenses, say post-2009; almost all of these are telecentric and of sufficiently high resolving power. Any of the SLR high end telephotos, RF telephotos
OK: RF normals, all other cheap telephotos; older Nikon MF glass; RF normals
Bad: Cheap C-mount/ CCTV lenses – these lack resolving power; RF wides

Ricoh GXR
Good: Any Leica M

Comments

  1. Yves Simon says:

    My classes in optics are too far in my past to know….. Should a 35mm lens for a reflex camera, adapted on a Micro Four Thirds camera, be better than a 35mm lens for rangefinder adapted on a Micro Four Third camera? The reflex lens will be physically farther from the sensor, but the optical center? Are the rays of light reaching the corners of the sensor more orthogonal with the reflex lens, or are the angles equivalent for the reflex and the rangefinder 35mm lenses?

    • Assume that a lens designed to purpose for a certain system and flange distance is going to be better than an adapted one, since it was also designed to work with the fixed optical parts of the system – i.e. sensor, micro lenses, cover glass etc. And that’s saying nothing about the possible planarity issues involved with adaptors…

  2. Yves Simon says:

    I would like to use a 35mm on an Olympus E-M10-II. I tried a Nikon 35/2.5 S and a Pentax FA 35/2. Disapointing: the edges with the Nikon are very bad, the Pentax is bad on the whole field at full aperture. I selected two lenses that look great, the Canon 35/2.0 L39 and the Canon 35/2.0 New FD. But I am tired of buying / trying / selling. Which one should give me the best I.Q.?

  3. Ming,
    For the following does exception mean they are bad? Best Wishes – Eric

    Micro Four Thirds
    Good: SLR high end telephotos, SLR normals, RF telephotos. Exception: Zeiss ZF/ZF.2 glass, Leica 35/1.4 ASPH FLE.

    • They’re not as good as the native M43 lenses. I think it has a lot to do with field curvature and lack of telecentricity – this is very important for small, high density sensors because of photosite shading issues.

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