Reading a recent forum post on using Leica lenses on Micro four thirds cameras we felt there was an amount of misinformation and some misleading recommendations. The originator of the post asked if the current m4/3 sensor, made by Panasonic, was incapable of resolving Leica lenses. In some of the replies there seemed to be an exaggeration of the difference that Leica lenses make to the results obtained by m4/3.
While being enthusiasts for the m4/3 system we would hesitate to make over-hyped claims about the quality of that sensor and would be concerned if people were contemplating buying Leica lenses in the belief that they would get substantially "better" results from their m4/3 cameras. Since Leica and most M-Mount lenses are comparatively expensive this could prove a great disappointment.
There is no doubt that the Panasonic sensor is an excellent one and in terms of comparison with other 12MP sensors at low ISO's it more than holds its own. There are concerns about the dynamic range but it gives very pleasing and high quality results. However having used a series of M-Mount and other lenses with it, we would hesitate to say that buying alternative or legacy lenses of any brand will provide resolution and sharpness advantages over the currently available Panasonic and Olympus lenses.
There are very good reasons to use non-proprietary lenses on m4/3 cameras. There is only one genuinely "fast" lens in the entire system and that is the Lumix 20mm f1.7 pancake lens. If you want other focal lengths with large apertures then you will have to look elsewhere. We use lenses such as 35mm f1.7, 50mm f1.2, 85mm f1.8 etc. none of which are, or we suspect likely to become, available anytime soon. However to assert that using these alternative lenses will give sharper results and higher resolution is we believe misleading. We have found no evidence of this and in fact have always stated that we find many of the branded m4/3 lenses to be of excellent quality, particularly the 20mm f1.7 and 45mm f2.8 lenses from Panasonic.
The image at the top of the page is the results of tests we carried out. It is hosted on flickr and there you will be able to download the largest size which gives an idea of what the comparisons are.
We tested the Panasonic 20mm f1.7 against a Zeiss 21mm f2.8 M-Mount lens at 3 different apertures. f2.8. f5.6 and f11. We used a GH1 at ISO 100. As a further comparison we photographed the same setup using a Samsung NX10 + 30mm f2 lens and a Leica M9 with a Voigtlander 35mm f1.7 Ultron lens. The results are on the image.
We could not see any significant difference between the 20mm f1/7 and the Zeiss 21mm f2.8 in terms of sharpness. There was a slightly different colour balance but that was all. The Samsung NX10 was very marginally sharper but there was so little in it that we don't regard that as being significant. The Leica images were easily the best of all, which is what we would have expected.
This confirms to us what we suspected all along, that the sensor is the element in the camera /lens/quality equation that has the most impact on image quality. We would advise that if you are considering buying an expensive M-mount lens in order to achieve a higher level of sharpness and resolution, that you be wary of people telling you that they are worth the extra money. We have no evidence that is true. You may well want to use a lens with with a wider aperture, but other lenses such as the Canon FD range or the NIkon F range will provide that at a much lower cost. You may well want a small lens and M-Mount lenses can certainly provide that, though do remember that most are made of metal and while small may be substantially heavier than their modern plastic equivalents.
Micro four thirds is what it is. A high-quality small light alternative to a DSLR. Adding a Leica (or other high quality M-Mount) lens may make your camera look good, but don't expect to add a Leica lens to a m4/3 camera and expect to get Leica type results. It just won't happen.