It's flare, the result of shooting against the light. A lens hood is useful for blocking light that comes from the sides. If you want to block light coming from the front... I'll let you deduce.
Given that you have the DS lens, I suggest you close the viewing lens diaphragm. You might be able to preview flare spots and perhaps avoid situations.
The Mamiya TLR lenses are very good, but their coating is not in the same range as the Zeiss &c.
__________________ Using film since before it was hip. |