Certo Bee-Bee lens removal?

[Pitxu]

I've read somewhere that the lens of my Certo is interchangeable.

I've rotated the cam shaped retainer shown in the photo, but the lens will not move, just rotate a very little.

Is there a particular direction in which to push, pull or twist it?


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Thanks.

 

[John Koehrer]

From the direction of the locking slot in the cam, I'd venture to say the shutter has to rotate anti-clockwise for removal.
Disclaimer:
I've never seen one of these in my life so proceed with caution.

 

[Pitxu]

Thanks John,
I think that the cam just releases pressure on a spring which goes all around the lens, some kind if circlip.
When the tension is released I think that the lens should just pull out cleanly, to the font.
Maybe there's something gummed up.

 

[John Koehrer]

Can you see what's happenin' from the inside?

 

[Pitxu]

With the cam in the released position the lens will turn left and right a little, but "crunchy".
From the inside I can see this lens movement. There is no retaining ring screwed onto the inside of the lens.

In this photo from behind the lens you can see the ends of circular ring which is tensioned by the cam.
I can only see it here, at the top. I think it must be gummed up round the sides and bottom. The lens has probably never been off before.

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