mikerfns Offline Upload & Sell: Off
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No need to do any serial number sleuthing.
The lens is definitely pre-AI. There is no AI coupling ridge on the back surface of the aperture ring (http://www.zi.ku.dk/personal/lhhansen/photo/mcr.htm), and no EE post (http://www.zi.ku.dk/personal/lhhansen/photo/EE.htm).
That is why the camera doesn't "recognize the lens" when you change the aperture ring setting with the non-CPU lens data entered. There is no coupling ridge to engage the AI coupling tab on your D7000, and the lens needs to engage and move that tab in order for the camera to recognize that you have moved the aperture ring. Normally pre-AI lenses should not be mounted on a D7000, as the extended rear skirt of the aperture ring on some of them can jam onto and potentially break the AI coupling tab, but that doesn't appear to be the case with this one. There is almost none if any material extending beyond the face of the mount flange, and in fact it appears to be flush and level with the mount flange surface. That is apparently quite common on third party pre-Ai lenses like the Vivitar above.
That means an AI conversion will require *adding* material to the back of the aperture ring to create a coupling ridge, as there is nothing there to mill away to create a ridge to engage the camera metering tab. I don't know if John White will do that type of conversion, but you can email him and ask. I do know that William Sampson does that type of conversion ... on a part time occasional basis. (http://www.aimodification.com - go the bottom of page and click on "unusual modifications" link)
No need to use "guess-by-histogram" metering though. The camera will still give you an accurate meter reading at maximum aperture for this lens if you enter the maximum aperture into the non-CPU lens data. So you can take a meter reading (in M mode), and then adjust your shutter speed setting (slower) by the number of f/stops you are set from wide open on the aperture ring. Not as fast as aperture priority (which won't work), but it only requires some simple on the fly arithmetic.
Mike
Edited on Jul 29, 2013 at 07:22 PM · View previous versions
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