Thursday, 25 February 2010

autofocus adaptor for micro4/3 - rumors are afoot


a rumor site 43rumors has just put an article out discussing a potential adaptor from Olympus for micro 4/3 cameras to adapt manual lenses and importantly add at least one (and perhaps two) features:
  • auto focus (for sure)
  • aperture (one certainly hopes so)

adaptorThe rumor suggests that the adaptor will reduce the focal length by 2 meaning that your 200mm lens will have the same view as a 200mm lens on a full frame camera.

Now for those of us who have been used to 4/3 giving us x2 advantage in focal length (making a 200mm into a 400mm) this sounds a bit poor, but it brings with it the advantage that light gathered will be essentially doubled so that could mean an extra stop of brightness.

Suggestions are that this could actually work well. A poster on one forum has suggested that this technology works well in Telescopes:
Focal reducers are common in astronomy, you take a 2000mm f10 SCT lens and drop it down to 1000mm f5.0. Wider field, faster, etc. But you don't see them for camera lenses. You can get a well-corrected f5-f6.3 focal reducer for telescopes for about $150.00.
Also the adaptor is rumored to be equipped with a SWD focusing mechanism, which sounds great as the SWD technology of Olympus is similar to the Canon USM.

While all this sounds very positive, in communication with a friend I was given this information relative to a previous historical precedent in Nikon's stable:
However, because of the small diameter of the entrance pupil of the relay system due to the limited space in the lens mount, any f-stop wider than f4.8 could not be used. Consiering that the space in the 4/3 or m4/3 adapter is also very limited (if you are to incorporate AF mechanism, the space should be even more limited)

which is less than ideal if you ask me. Time will tell.

For those who are interested, here are some links:

interesting times


Lens Bubbles said...

I don't see why this is not possible. Pentax has a 1.7x converter/adapter that auto focuses with manual focus lenses (ok, not very slow lenses). As for the aperture, this is quite possible. Leave the lens set at wide open, and the adapter stops down its own aperture on the adapter. The only problem is that each lens has different design for aperture opening to achieve a specific f-stop, so the aperture oopening for f2.0 on one lens is not the same as another lens.

Eric said...

The 2x advantage you talk about is great for long focal lengths but it's a disadvantage if you want wide angle lenses. I'd love for my 24mm lens to have the equivalent field of view on my G1 as it does on a 35mm film camera...

obakesan said...


exactly ... and this is why I'm considering getting a 5D ... to get access to shallow normals and good wides. Search my blog and you'll find I'm advocating exactly that.

Meantime the G1 does make a handy birding and portrait camera with legacy 50mm and 300mm lenses

Eric said...

Yes, I've read (and continue reading ;-) your blog. I have no interest at all in going back to a large DSLR! I love the size of the G1 and its ability to make use of all of my legacy lenses.

You're right that it makes a good portrait camera. I also like it for street photography. What I would like is to improve its capabilities for landscapes where I do want wider lenses than I currently have.

obakesan said...


yes, I agree entirely about wide angle lenses on the G1 for landscape. I have high hopes for this adaptor as I would love to be able to use this with my Olympus 21mm to get sweet wides!