Contax Zeiss lens on 40D, overexposure problems

I bought some Contax-to-EOS adapters to try out my Zeiss 28 and 35 mm lens on my 40D. I set camera to Aperture Priority mode and focus/autofocus with the aperture wide open than stop down to take a couple of pics but they all come out overexposed.

When you stop down the viewfinder gets dim so I was told to use average metering but I tried all modes: evaluative, partial, spot, and center (I may have gotten the nomenclature wrong) but I still get overexposed shots.

If I take pics at max open aperture, e.g. f2.8, exposure is fine but of course I don't have much depth of field.

Now I tried all of this last night under fluorescent lighting and the adapter manufacturer said to 'shoot outdoors' so I don't know if that is a factor.

this is strange. I do this with all my manual lenses, including Contax, and my images are ok. I don't have a 40D. I own a 20D and a 5D, and both work just great with manual lenses. I would expect the 40D to be the same. Could you post a sample picture with exif?

tiziano wrote in post #6235558
this is strange. I do this with all my manual lenses, including Contax, and my images are ok. I don't have a 40D. I own a 20D and a 5D, and both work just great with manual lenses. I would expect the 40D to be the same. Could you post a sample picture with exif?

I'm still figuring out how to post pics on this site. I have some 10 MP JPEG pics; if somebody can tell me how to make them in Photoshop quick-and-dirty.

I took pics in the same spot on the Canon 28-135 lens and a Zeiss 28 mm. The Zeiss shots were way overexposed, however exif was not the same (I think I shot the Canon lens on AUTO). Fixing in Photoshop helped but did not get the Zeiss pics back to the Canon lens, exposure-wise.

You will have to resize in Photoshop your image until is smaller then 150k, (Edit -> resize) and then you can attach it to your post. Or you can publish your image on one of the picture sharing web sites, and post only the url to the image here.

I have a BUNCH of manual lenses, stacked up out there like firewood. My brand new 40D does a horrid job metering most of my manual lenses, compared to my Xt, which is not perfect, either.

The 40D is MUCH more unpredictable, sometimes going from overexposed at one aperture range, to halfway decent in the middle, to somewhere else in the small end. I've gathered a bunch of my lenses---I have something like 5 different lenses in the 50-55mm range, and all do this to some degree.

I'm very disgusted, I was looking forward to the bigger viewfinder, and live view to help with focusing problems, and now this.

My only plan at this point is to pick certain lenses, and document and chimp them to figure out 'where they are.' Worse, I just bought an Elan II body to do a few film experiments. I'm quickly losing confindence in the metering in these cases.

Clevor wrote in post #6235463
I bought some Contax-to-EOS adapters...

Where? Does it convert Contax G2 lenses to EOS?

440roadrunner wrote in post #6236185
I have a BUNCH of manual lenses, stacked up out there like firewood. My brand new 40D does a horrid job metering most of my manual lenses, compared to my Xt, which is not perfect, either.

The 40D is MUCH more unpredictable, sometimes going from overexposed at one aperture range, to halfway decent in the middle, to somewhere else in the small end. I've gathered a bunch of my lenses---I have something like 5 different lenses in the 50-55mm range, and all do this to some degree.

I'm very disgusted, I was looking forward to the bigger viewfinder, and live view to help with focusing problems, and now this.

My only plan at this point is to pick certain lenses, and document and chimp them to figure out 'where they are.' Worse, I just bought an Elan II body to do a few film experiments. I'm quickly losing confindence in the metering in these cases.

The overexposure I am experiencing is a bit more consistent, but those adapters are so expensive (the Haoda ones are $75 each) it's not like I can afford six of them for all my Zeiss lenses. So far I've tried my 28mm and 35mm on two different brands of adapters and the problem is the same.

What I find works fairly well is set the camera to underexpose pics by about a full stop (I move the ON switch up, pointing to 1 PM, where you can set each pic to be over- or underexposed the same amount). It's still a bit off from perfect exposure but can be fixed suitably in Photoshop.

I tried the AE Lock at wide open aperture, than stopping done and taking the pic but no go. I also notice some other bugs where the camera will shoot at 6 FPS when set to AP-DP (or whatever is that) mode where each pic has maximum depth of field.

I guess not many people have been trying these Zeiss lenses on the 40D so far . . .

Clevor wrote in post #6237190
The overexposure I am experiencing is a bit more consistent, but those adapters are so expensive (the Haoda ones are $75 each) it's not like I can afford six of them for all my Zeiss lenses. So far I've tried my 28mm and 35mm on two different brands of adapters and the problem is the same.

What I find works fairly well is set the camera to underexpose pics by about a full stop (I move the ON switch up, pointing to 1 PM, where you can set each pic to be over- or underexposed the same amount). It's still a bit off from perfect exposure but can be fixed suitably in Photoshop.

I tried the AE Lock at wide open aperture, than stopping done and taking the pic but no go. I also notice some other bugs where the camera will shoot at 6 FPS when set to AP-DP (or whatever is that) mode where each pic has maximum depth of field.

I guess not many people have been trying these Zeiss lenses on the 40D so far . . .

$75? Have you bought the adapters with the electronic chip for focus confirmation? As the ones without cost around $15.

tiziano wrote in post #6237586
$75? Have you bought the adapters with the electronic chip for focus confirmation? As the ones without cost around $15.

Yes, I am buying the ones with AF confirmation. The one from Haoda for $75 has the best fit and least slop but is hard to put on/take off the lens. The one from Big-IS is half the price but has a bit of slop, but works. This one can be easily taken off the lens. No way I am paying $175 for the Kindai or Cameraquest ones.

I'm finding the AF confirm is not a big deal. Focusing though the viewfinder isn't a big deal if you are on a low budget.

jr_senator wrote in post #6236204
Where? Does it convert Contax G2 lenses to EOS?

Not sure about that adapter. You can find these adapters on Ebay:

http://search.ebay.com …to+eos+adapters​&category0=

Clevor wrote in post #6235463
I bought some Contax-to-EOS adapters to try out my Zeiss 28 and 35 mm lens on my 40D. I set camera to Aperture Priority mode and focus/autofocus with the aperture wide open than stop down to take a couple of pics but they all come out overexposed.

It's something to do with the metering on the latest set of Canon DSLR's. I get the same problem on my 450D regardless of metering mode but the same lenses with the same adaptors meter perfectly on the 1D2 and the 300D. I mean it's not just off by a bit, we're talking 2+ stops at f/8.

Frankly I just used it as an excuse to go back to [M]anual mode on the camera and enjoy the experience of reading the light and the satisfaction of getting it right.

Clevor wrote in post #6237778
Yes, I am buying the ones with AF confirmation. The one from Haoda for $75 has the best fit and least slop but is hard to put on/take off the lens. The one from Big-IS is half the price but has a bit of slop, but works. This one can be easily taken off the lens. No way I am paying $175 for the Kindai or Cameraquest ones.

I'm finding the AF confirm is not a big deal. Focusing though the viewfinder isn't a big deal if you are on a low budget.

Maybe the focus chip is messing up some how? Have you ever tried with an adapter without focus confirmation?
Anyway, I have the adapters with focus confirmation too, and they work just fine on my cameras.
Still not able to post a picture?

Well let's see if this works. I changed the image size to 800 pixels (width) and saved as #5-MED and file comes out to around 98-110 kb:

This is shot with the Canon 28-135 lens and 40D set to AUTO:

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The focusing chip DOES change the problem, not necessarily for the better or worse, just changes it. I have a plastic washer I made for my Tamron extender, which fits in the camera and insulates the contacts for certain uses.

I can therefore use/ not use the chip.

Many of my problems ARE MORE TAN +/- 2 using the 40D, which means I cannot take care of the problem with EC. I must use manual, and chimp around to find the combo. Pretty much negates these for casual shooting, and MUCH worse metering than my 350D.

Above looks OK. This is the Zeiss lens but I don't know the exact exposure settings; I just know I stopped down to around f11-16? Camera was set to AP priority:

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