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Re: [OM] Some lens testing - Emf chip on OM=>EOS adapter

Subject: Re: [OM] Some lens testing - Emf chip on OM=>EOS adapter
From: Moose <olymoose@xxxxxxxxx>
Date: Thu, 28 Apr 2011 01:55:06 -0700
On 4/27/2011 3:35 PM, usher99@xxxxxxx wrote:
> Moose reports:
>> I recently bought an Emf chipped OM=>EOS adapter. It's kind of a pain to 
>> program, using up lots of shutter cycles.
> Thanks for the report on the emf chip and the lenses. I was waiting on the 
> former and the latter was interesting.
> Seems the chip is a one trick pony, but it is a very good trick.


Well, three tricks, isn't it? Report maximum aperture, convince the camera it 
has set the aperture to what the camera 
asked for and adjust micro focus.

> As I understand it, it reports the widest aperture of the lens (that one 
> sets) to the cam

Correct

> , then reports the 'real aperture" set on the cam for the proper exif

Yup, it puts whatever you dial in into the EXIF. It's your responsibility to 
coordinate camera and lens

> , yet still has the AF confirm work as long as the widest aperture setting is 
> adequate for it to be turned on.

Yes, that's how it seems to work, by giving a maximum aperture and, perhaps, 
responding in some way to the camera's 
command to set aperture.

> I think at very wide apertures there may be a more precise AF mode, IIRC

Yes, starting at f2.8, I believe.

> so I usually report F1.4 to the cam on my optix V chips.

I would think that might cause poorer performance. Those sensors aren't 
activated unless there is enough light for them, 
so fooling them might cause them to try to function with inadequate light?

> The chips I have though only report the aperture to exif that is programmed 
> into the chip so one has to change it after focusing
> and that is a pain (doesn't happen very often in actuality).

I can't imagine doing that very often. The emf chip solution of using the 
camera setting is quite easy and practical. 
Once the chip is programmed for a focal length and speed, operation is quite 
simple.

> It activates programming with the dof preview which is way better than the 
> shutter. If there were a chip that combined the best aspects of both, I would 
> change every adapter to them.

Yup, the DOF button would seem easier on the camera. Emf functionality 
programmed through the DOF button would be very 
nice. What would be really nice would be a USB connector that clips onto the 
chip contacts and allows instant 
programming with preset profiles. Could a 'phone app do that with a special 
connector?

Moose
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