View Full Version : Really stupid question

16th July 2010, 07:11 AM
But what's the difference between four-thirds and four-third micro lenses?


16th July 2010, 07:43 AM
The quick answer is "about half an inch"

The proper answer is they made micro 4/3 cameras smaller by removing the mirror. This means the camera is thinner and m4/3 lenses sit about 1/2 inch closer to the camera, so they are all new designs.

The theory is that you can buy an adaptor and fit your old "ordinary" 4/3 lens on your m4/3 camera body. The adapter places your old lens where its prefers to be (1/2 inch further away from the camera) and it also does all the electronics stuff to make the lens work. 4/3 lenses don't always focus as fast on a m4/3 body, so I gather.

The other side is - you can't fit a m4/3 on an ordinary 4/3 camera body. Its not possible at all.


16th July 2010, 10:52 AM
Its not a really stupid question.
I learnt something as well.


16th July 2010, 11:11 AM
The difference in flange/back distance is about is just under 2cm, so a fair but more than half an inch (1.27cm).

I guess someone could develop an adapter to enable the mounting of a Micro Four Thirds lens onto a Four Thirds camera, but the arrangement would be like using an extension tube, so there would be no possibility of focusing to infinity. In theory, though, you could engineer to to pass through focus and aperture data I suppose.

As micro four thirds lenses sit much closer to the sensor than four thirds lenses, the power of the optics, particularly with wide angle lenses, need not be so great and the design of the elements can be much more compact.

I wrote an article that attempts to explain this here: