In my last article I mentioned the main reason to consider a move to the Micro Four Thirds format: smaller cameras. The photo above shows my usual Pentax K20D with FA 43 f/1.9 Limited lens, a superb optic that is perhaps the best Pentax offers. Behind it is the Olympus E-P1 with Panasonic Lumix 20mm f/1.7, again likely the best lens available for this system. Obviously there is a significant difference in form factor. If I had the newer K-7 or K-5 cameras they would be appreciably smaller, but a substantial difference would remain.
I have a second picture to show you, but first I need to explain an important feature of MFT, one that helps explain the compact size but which also provides a further significant advantage.
The MFT flange focal distance (AKA register), the distance from the lens mounting flange to the sensor plane, is practically the smallest of any photographic system. In other words, MFT lenses sit very close to the sensor. The upshot of this is that any lens from camera system with larger flange distance can be readily converted for use on an MFT body, using an adapter that does two things: a) provides a suitable coupling for the third-party lens and b) makes up the difference in register so the optics focuses light on the correct plane.
Here is a listing of some suitable lens systems. Note that though the C-mount distance is smaller than MFT, there is still enough clearance of the rear lens assembly in most cases.
C = 17.526mm
Sony E mount = 18mm
MFT = 20.00mm
Leica M = 27.95mm
Pen F = 28.95mm
Leica M39 = 28.80mm
43 = 38.58mm
K / M42 = 45.46mm
OM = 46.00mm
Nikon F = 46.50mm
Leica R = 47.00mm
This fact has led to a profusion of available adapters and a new demand for older lenses. Suddenly, orphaned lines that worked only with old film cameras now have a new life on digital. Even in cases where digital bodies do exist, Leica for instance, an MFT camera costs one-tenth as much and allows use of the same amazing optics. This, not the small size, is perhaps the biggest contribution of MFT to photography.
The most logical thing for me to do, since I already own a good number of Pentax lenses, was to get a K-mount to MFT adapter and see how the combination worked. You will be pleased to learn that is exactly what I have done, as the following photo makes clear.
The Pentax K20D is again compared with the Olympus E-P1, but this time both have the FA 43 f/1.9 Limited lens mounted. The rather large adapter is prominent. This is a cheap eBay job that cost twenty bucks. Obviously the size advantage of the MFT system is eroded due to the register requirement. But I look forward to checking out some sample photos, which seems like a good subject for my next article.
Oh, in case you were wondering, that's a double exposure. I only own one FA 43 Limited!