Owners of Leica lenses will be looking with interest at Sony’s new A7 cameras. In the past couple of years there has been huge demend for information on matching Leica lenses with APS-C and even M4T mirrorless bodies. The article I wrote last year on Leica lenses with the Fuji X-E1 is the most-read piece on Macfilos. Problem is that full-frame Leica lenses used on a crop-sensor become longer, with double the focal length on M4T. The semi wide-angle 35mm Summicron becomes a medium tele of 70mm on a Micro Four Thirds body. Other optical glitches can occur as Leica fans are quick to point out.
Now, for the first time, owners will have the opportunity to try out their Leica glass on a real full-frame camera, thus preserving the original focal length and opening up the full gamut of lenses to experimentation. But, before getting too excited, we will have to wait for the first real-world tests. According to some experts I have discused this with, use of Leica lenses on non-M full-frame cameras could bring a number of problems. Purists say that the M is the only camera that is perfectly tuned to Leica lenses. This is ultimately true, but it will be interesting to see how close we can get to perfection with the A7s. I suspect many Leica owners will be tempted to invest in a Sony body just to try out their lenses and see what results they can get.
This article goes into some of the complexity and difficulties that can be expected and is worth a read before splurging on an A7 body.