Canon 1Dx, Nikon F to EOS Fotodiox Adapter Issue?

[A.T.]

Hello all wise and knowledgable DSLR shooters.

I'm shooting with a Canon 5D II and Canon 1Dx. I've just been using my Canon EOS lenses until recently. I've bought a few older Nikon F mount AiS lenses, 24 f2.0, 35 f1.4, and 50 f1.4, specifically to shoot video with. I've bought basic Fotodiox adapters for the Nikon lenses.

Here's my issue. In live view mode with the 1Dx and my Nikon lenses the  match needle meter readings are 2 stops lower than when using the meter through the traditional view finder (non live view). If I shoot a test still frame using the viewfinder metering I get a proper exposure. I check the histogram. It's all good. I check the histogram through live view of the same image composition. It's consistent with the histogram of the test still image. But the match needle reads 2 stops lower.  

So basically the meter needle in live view reads 2 stops lower than the needle in the view finder.

This is an issue because I tend to shoot using the match needle metering in live view.

To complicate things on occasion the live view image will also appear drastically dark/under exposed. Unfortunately that happens so sporadically that I haven't been able to determine any consistent circumstances.

And none of this is an issue with my 5D II. It works perfectly fine. 

I just picked up the 1Dx form Canon. They checked everything over and made some minor adjustments to the metering. $200 later and I still have the problem. So I tested my lens and adapter on one of their 1Dx loaners and it did the same thing. So this is something specific to 1Dxs and these Fotodiox Adapters and Nikon f mount lenses.

My next step will be to try another brand of adapter. I should add that this Fotodiox adapter is the simplest kind, purely mechanical, no electrical connection features, stop down meter.

Is there anyone out there also shooting with Nikon manual focus F mount lenses on a 1Dx? I am stumped. Any feedback would be much appreciated.

Thanks.

[A.T.]

I should add that I also have a Zeiss 180mm f2.8 with a Canon mount and I have the same issue. So this not an issue of the Fotodiox adapter specifically. This seems to be about using a non EOS lens/manual focus lens on a 1DX.

Still scratching my head though.