I have a 13" wollensak apo raptar f10 in barrel. does anyone know anything about this lens? it is reputed to be the same formula as an artar? I use it on a 5x7 with a packard shutter but I question its sharpness as it doesn't seem to perform as well as my 240mm G-claron. I admit lately I have used it at rather wide apertures f22-32 due to wind and lighting conditions. But still the contacts don't seem to measure up to my 4x5 contacts when viewed with a loupe. any thoughts? All negatives are the same film(foma 200) developed the same(d-23 2:1).