Author Topic: AF Confirm Adapter (Read 3263 times)

xin668 · « **on:** February 14, 2010, 08:18:05 AM »

Have anyone found AF confirm adapters for micro 4/3 cameras? I know that there are such adapters for 4/3 cameras. Do you think I can attach a combination of MMF-1 and AF confirm adapter for 4/3 to do this? The MMF-1 adapter is little expensive though. Thanks.

adash · « **Reply #1 on:** February 14, 2010, 08:46:02 AM »

It <should> be possible to use mmf-1 with an af-confirm adapter. What the AF confirm adapter does, in my point of view, is to lie to the camera body that a lens is present and that the lens is executing commands over the wires from the camera (i.e. focus further/nearer, aperture setting, aperture fully open, etc.) without actually doing this.
Again in my point of view, an mmf-1 is something you would buy anyway, if you want to use big glass from the 4/3 system.
As far as I know, there is an ongoing work for bringing up an af-confirm chip/adapter for the m4/3 system, but progress so far is unkown.

Olof in Amsterdam · « **Reply #2 on:** February 14, 2010, 05:21:27 PM »

In October 2009 I had an e-mail discussion with one of the Hong Kong / e-Bay manufacturers about AF-confirm on MFT adapters. Their conclusion was: impossible because of the nature of the contrast detect AF system. I don't remember the name of the manufacturer.

xin668 · « **Reply #3 on:** February 14, 2010, 06:00:59 PM »

One thing that troubles me is the optic side of this combination. The length between the lens and sensor is definitely not the same as adapters designed for micro 4/3.

I am trying to attach Leica R lenses to a micro 4/3 camera. The length of the adapter combination and adapters designed for micro 4/3 seem to be fairly close. So I wonder what other disadvantages this combination might cause.

Thanks for the great info.

swandy · « **Reply #4 on:** February 15, 2010, 08:29:04 PM »

Like Olaf said - since the AF systems of the two cameras are totally different (Phase Detection vs CDAF) I would imagine that an AF Confirmation adapter that is made for the 4/3 cameras would not work on a m4/3 one.

As far as the lens optic to sensor distance, this is the main reason that it is so simple to adapt older lenses to the m4/3 mount, because it is so short. I don't have any Leica lenses (wish I did), but I have mounted several Olympus OM lenses and a Lensbaby (4/3 mount) using adapters and have had no problems whatsoever.
Steve

adash · « **Reply #5 on:** February 16, 2010, 04:08:18 AM »

Quote from: swandy on February 15, 2010, 08:29:04 PM

Like Olaf said - since the AF systems of the two cameras are totally different (Phase Detection vs CDAF) I would imagine that an AF Confirmation adapter that is made for the 4/3 cameras would not work on a m4/3 one.
Steve

All DSLRs that can shoot with the mirror locked up (a.k.a. LiveView) use CD for autofocusing in that mode as well. 4/3 DSLRs make no exception. Please also note that all AF logic is in both cases in the camera body, not the lens.
Correct me if I'm wrong.

Olof in Amsterdam · « **Reply #6 on:** February 16, 2010, 07:52:45 AM »

Adash, you are right. I just tried live view contrast detect focus on my Canon 5DII. It takes up to a pathetic 5 seconds to focus and even then the result can be way off... That's why the manual does not recommend it and tells you to use phase detect (mirror will come temporarily down) or manual focus.

I am now beginning to appreciate the "fast" AF of my E-P1!

adash · « **Reply #7 on:** February 17, 2010, 12:50:58 AM »

@Olof in Amsterdam
Theoretically the lens does the same in PD and CD AF modes. The big difference is that in PD the camera body knows in which direction to pursue sharp focus, while pure CD systems have to go all the way to infinity (or closest distance, depending on manifacturer's preference) and then backwards in order to reach it.

Have you noticed how little travel the 14-42 kit lens has from closest focusing distance to infinity? I have no other AF lens to compare it with, but I assume Canon glass travels much more, even if it rotates with the same speed, since it is designed to work with PD AF and the manifacturer was satisfied with the total time it takes to reach sharp focus. The same with the "fast" AF in PEN - it takes less to focus in CD mode, since it has less travel and goes through the whole process faster, so the total time to reach sharp focus is still acceptabe.

So, theoretically, an AF Confirm adapter <should> work, since it has nothing to do with focusing itself. Such adapters do the simple task to lie to the software in the camera body that a lens is present. If I had the funds, I would give it a try, since the MMF-1 is anyway an investment, and an AF Confirm adapter is something I could easyly sell to fellows on the local market, should the experiment fail.
Do you agree with me?

Olof in Amsterdam · « **Reply #8 on:** February 17, 2010, 04:58:56 PM »

Adash,
I really don't know enough about the technical aspects of the subject. My Canon lenses all have internal focusing systems, so I can't compare the travel. But I do have a Sigma 50mm/1.4 which travels about 8mm from 0.45m to infinity. My Lumix 20mm/1.7 needs 4mm from 0.2m to infinity. They have the same amount of travel if you consider the difference in focal length. I expected this, because there are physical laws that apply here.

The only way to speed up focusing would be to move only one or two elements of the lens. The moving part will become lighter and focusing will become faster.

My 2 cents...

xin668 · « **Reply #9 on:** February 17, 2010, 11:55:21 PM »

The MMF-2 adapter is about to come out, I hope the price of MMF-1 will drop a little.

AF Confirm Adapter