Questions about the Mechanics of Legacy Lens Focus and Exposure


Mu-43 Regular
Sep 19, 2012
I'm fairly new at some of the more esoteric M43 options, but I have a couple of very nice condition, older Nikkor AIS lenses, the 105mm f/2.5 and 135mm f/2.8, and I"m wondering about the M43 adaptors for Nikon F-mount lenses to enable their use in manual mode on my GX7.

Using the adaptor mounting one of these Nikkors on the GX7:

1. Will the EVF (which I realize is not in any way a ground glass, but is presumbly directly reporting an image passed to it electronically by the camera body's sensor) show a reliable image of "sharpness" as the lens is manually focused wide open? I understand that, after focusing, I'd close down the diaphram, using the lens barrel, to the shooting aperture.

2. Would "focus peaking" work in this process?

3. If the GX7 mode is aperture priority, would the camera body metering system adjust the shutter speed to the correct exposure based on the shooting aperture and set ISO at time of squeezing the shutter?

4. Would one instead set the GX7 for manual mode and manually adjust the shutter speed as well as the shooting aperture on the lens barrel?


Mu-43 All-Pro
Aug 23, 2012
Denver, Co
Real Name
Sean Rastsmith
1 Yes, it will show whay is in focus. You can either focus wide open and then stop down, or focus stopped down

3/4 You can shoot in either aperture or Manual mode, and the shutter will vary accordingly.

Sent from my LG-P769 using Mu-43 mobile app


Mu-43 Hall of Famer
May 17, 2011
Washington - The Evergreen State
1. - stopping down after focus generally does not work so well for me.

2 yes but not so much for some. I dont use it but it does work alright.

3 yes as you described. I mostly shoot in A mode with manual/adapted lenses although some times use M mode or otherwise restrict ISO in A mode.

4 Depends on the task at hand.

I'm really liking the metabones speed booster so if you have the budget or access to one then really give that a sincere look. I have 6 or 8 (hard to keep track sometimes) manual lenses that I can use the metabones with so it really extends the range of coverage in both focal length and aperture I get to work with so the added cost 'amortized' is quite low (that's the pitch I give to the wife when costs come up).


Mu-43 Veteran
Sep 23, 2012
Real Name
A couple things worth considering:

-as far as the metering goes, the further you stop down the further off the metering can be so you'll want to be aware of this. I don´t remember exactly how it works but hopefully someone with a better understanding will chime in.

-One other thing I´m somewhat hesitant to mention is that m43 cameras have a somewhat thick sensor stack which can cause some problems with older manual focus lenses. I use a Canon FD 50mm 1.4 from time to time but since upgrading to the E-M5´s 16mp sensor in comparison to my older E-PL2´s 12mp sensor, I´ve not been as happy with the results and so I think there might be some truth to this problem and I´m just now able to notice it more. Here´s the blog post on the subject:

I don´t think either of those concerns should put you off from trying out your lenses though since it can be a lot of fun to give new life to older glass

ex machina

Mu-43 Hall of Famer
Jan 3, 2014
Baltimore, MD
When I shoot manual lenses on my GX7 I almost always use aperture-priority mode, but you can also use manual mode if you need to. Focus-peaking is a god-send for me and my older eyes, and I really wish my GX1 had that as well. If you wish you can enable the GX7 to display at the chosen aperture to get a sense of the DOF you are shooting for. You may find that focus-peaking works better when the lens is stopped-down.
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