3stop overexposure with Zeiss CY lens/Haoda adapter on 5dmkII

Has anyone had this problem, knows of a solution? I have a number of Zeiss lenses with Contax mount, use a Haoda Pro adapter, and with all lenses, exposure comes out around 3 f-stops over with available light, regardless of metering mode used. So I now just use it in Manual mode, and look that the exposure indicator in the view finder blinks at -2 (i.e., more than 2 fstops underexposed).
With flash, it is ok.
Is this an adapter problem? Did I get a lemon camera (bought 12/09; with latest firmware: 2.0.4)?
I also have the Zeiss ZE 100 macro, and it tends to be overexposing as well, but only about 0.5 to 1 fstop, so can be salvaged in RAW processing, or set camera exposure correction.
The Canon 300/2.8 does fine, as well as the 65 MPE.

Does the camera think it can control aperture when it actually can't and is trying to stop it down? Make sure you have the camera (Av or M mode) with the aperture at the max value.

+ 1

Which camera? I have used manual lenses with adapters for years and noticed that starting around the era of the 40D something changed in the Canon metering system that means evaluative is usually way off when used in AV. Earlier cameras were usually close enough give or take. Now I just use manual mode and learn to read the light - it's actually been an education.

That doesn't work when the camera's metering doesn't respond linearly through the aperure range which is what often happens with manual lenses.

You virtually need to carry a table with you with compensation for all the apertures for each lens, since different lenses respond differently.

Wilt posted some tests he did with a number of different lenses to illustrate the point.

bohdank wrote in post #10101948
Wilt posted some tests he did with a number of different lenses to illustrate the point.

Test with five different manual focus non-coupled lenses on a Canon 40D (and the last text, below, with the 5D), showing the fact that as the aperture is stopped down the meter does not respond in a linear manner at all. I have found the best way to use any of these lens is to stop down to f/4 and meter, then alter both the shutter speed and aperture in a similar manner! (For example, if you want to shoot at f/9, you adjust aperture -2.33EV and alter shutter speed +2.33EV. Otherwise metering is absolutely NOT reliable!!!

I wouldn't expect the adapter to have any effect on metering. Usually, an adapter issue (too thick or too thin) would only impact infinity focusing. Also, there can be exposure variances between one lens and another of the same brand, as well as between brands, so its not uncommon for two Zeiss lenses to behave differently. Stopping down the lens will also affect the metering incrementally. Some third party focusing screens can also affect the metering. One other thing...did you change out the focusing screen in the 5D2 to the Eg-S screen? If so, you need to reset the screen option in your Custom Functions...this could also affect metering (although I suspect you probably didn't change out the screen).

Are you using stop down metering with the lens wide open? I shoot with plenty of adapted manual lenses (Zeiss, Leica, Mamiya, Oly) and simply use Av, center-weighted average, meter/focus wide open, stop down to my needed f-stop, and use my histogram and expose to the right under most conditions. If necessary, I'll use +/- EC accordingly when using ETTR. This works for me...

argyle wrote in post #10105822
I wouldn't expect the adapter to have any effect on metering....Are you using stop down metering with the lens wide open? I shoot with plenty of adapted manual lenses (Zeiss, Leica, Mamiya, Oly) and simply use Av, center-weighted average, meter/focus wide open, stop down to my needed f-stop, and use my histogram and expose to the right under most conditions. If necessary, I'll use +/- EC accordingly when using ETTR. This works for me...

The words in blue are the key to successful exposure with any non-coupled lens, regardless if the adapter has or does NOT have the focus confirmation chip in it!