Hello all, I bought a Yashicamat 124G, and was examining it. When looking through the taking lens on bulb, a prominent streak is seen. 1 o'clock: From the back; 11 o'clock: A closer look. 1 o'clock on both. Is this fungus? When viewed from the back, it is behind and close to the rear element. I gather that it is relatively simple to open this lens up, but I don't own a wrench spanner, and do not want to tamper with it unless I decide to keep it. Any idea or comments would be helpful. Thanks very much.