Polaroid 405 backs on a Technika V

[Dumb Handsome]

I'm very excited about using some Fujifilm FP100c and 3000b on this camera, and then scanning the negatives on my Imacon Flextight II. However, looking through the front lens board hole of my Technika with a Polaroid 405 back mounted on it, the rectangle of the Polaroid back seems to be uncentered, with the dark slide starting at the far left corner. Do Polaroid 405 backs sit correctly on a Technika V, or do they generally have to be modified?

[pierre506]

Using this one~
Or marking the size on your focusing glass according to this one~

[Bill_1856]

They've never been centered.