The Q was the single-coated tessar predecessor to the multi-coated M series. I own a set of the M's, including a 105/3.5. It's a wonderful optic for 6X9, but WILL NOT adequately cover 4x5, even at very small stops. You can get a "circle of illumination" slightly large enough to fill 4x5, but the rendition of the corners and edges will be awful. More often, I'm asked about the potential use of this lens for 6X12 roll film backs. But even point-blank, with no movements, it's a near miss : up to around 6X11 cm you get good resolution, but the far edges will be disappointing.