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08-29-2015, 08:47 AM   #1
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Join Date: May 2013
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pentax 645 compatible your 67

today I discovered something different, I tested two lenses 645, 300mm A* and A 35mm 3.5 and both cover the image circle of 67.

it is theoretically possible to use these lenses in larger format the problem is the distance
flange, which do not allow focus. Perhaps some sort of adaptation to use these lenses is possible in the body 67

08-29-2015, 10:45 AM   #2

Join Date: Feb 2009
Location: Arizona
Posts: 1,207
You would need to extend the focal length of the 645 lenses to be able to reach the film on the 67. Putting a weak negative achromat in front of the lens would do this, however those are not made for such purposes. The 1.4X rear converter for the 6x7 is a negative lens (afocal) but there is no guarantee that this would extend the focus long enough when used on the front of the 645 lens. The 1.4X converter will also greatly reduce the amount of light entering the lens.

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