Not on backwards, just rotated 180º. The silver ring you're seeing is actually a slot in the eyepiece for a blue filter. It is thought that a blue filter makes it easier to focus. Not necessary.
It just flips around for more compact storage if necessary. The optional blue filter was related to graded blue-sensitive paper days, and when enlarging lenses were less well corrected. The point is, you wanted to focus using blue light only. That is rarely an issue anymore.
Not on backwards, just rotated 180º. The silver ring you're seeing is actually a slot in the eyepiece for a blue filter. It is thought that a blue filter makes it easier to focus. Not necessary.
Not on backwards, just rotated 180º. The silver ring you're seeing is actually a slot in the eyepiece for a blue filter. It is thought that a blue filter makes it easier to focus. Not necessary.