I have an old 4x5 field camera with a very annoying problem. Periodically, it seems on particularly on bright days, I get a bright spot near the center of the negative. This is the negative This is the print. In the past I have been told to look for light leaks, I have examined the camera several times with a both a strong light bar lamp and a beam lamp. * The bellows do not show light leaks when partially of fully extended, when viewed inside through the lens hole or outside when lit from within. * With the film holder in position there is no light entering from the back of the camera. * When the lens board is mounted there are no light leaks from around the lens or lens board. This light spot does not always occur but it is usually in the same spot on the negative and as you can see from the shadows, the sun was above my left shoulder. I an wondering of this could be some sort of lens flare or a reflection off of some part of the camera. I am at a loss and open for any suggestions.