Rodenstock 80mm f4 problem

[karl burke]

Hi all,

Just got this Rodagon 1:4 f=80mm lens from Ebay, but for the life of me, I can't figure out how to change the aperture - the lens seems to be stuck, or I'm missing something here. I thought all enlarging lenses were a simple as a brick, but there you go. I tried pulling the front of the lens down when it was mounted on the enlarger, but it didn't shift. No rotation either, other than unscrewing the front lens group. I can't work out the function of the screw either.:confused:

Any help would be greatly appreciated !
thanks,
Karl

 

[keithwms]

I don't know this lens but I recall reading that there was a Nikkor EL lens that, if the adjustment pin was gone, required a toothpick or similar implement to change the diaphragm :rolleyes: Are there any access holes/slits?

 

[fotch]

It looks like a bolt head above the aperture slot, wonder if that has anything to do with it?

 

[John Koehrer]

There should be no mystery about using the lens. The aperture ring should rotate, the barrel should not. Normally the push-pull engages or disengages the click function. With color film you may want an exposure of f8+a tiny bit.
Think seriously about returning it.

 

[MattKing]

It looks like a bolt head above the aperture slot, wonder if that has anything to do with it?

I would agree - it looks to me that someone has added something to lock the aperture to a particular setting.

Matt

 

[Bob-D659]

I'd guess the lens was in a printing machine or a machine vision unit and the aperture was locked in place for a good reason. Odds are removing that hex head screw will unlock it.

 

[Ian Grant]

Lenses for roll head printers mounted in turrets often have a lock screw so that once set and calibrated all lenses give the same exposure times regardless of the lens used.

So unscrew that bolt, it maymay be locking the aperture, I had 2 turrets ful of Componons from a lab 4 years ago every lens had one.

Ian

 

[karl burke]

Well, I removed the screw, and it turns out that I can change the aperture by inserting the tip of a pen in a notch in the little window above the non-moving aperture ring. When I got the lens it was locked to the f4 setting, although there's a mark which seems to indicate a factory intention that it should be locked between f8 and f11.

I guess it could be a good lens, but to be honest I'd miss the illuminated dial and click stops. I'll see if I can get a return, although I should give it a go in the interim anyway. Thanks to everyone for their help.

 

[RobertV]

Before you take the lens apart:
All Rodagons have a F stop limiter which you can activate by pull the ring and turn. In this way you can make the lens in one turn to the disired F working aperture.
On the side there is a switch and here you can select clicks or without clicks.
All Rodagons have an illuminated aperture ring so this should work will all enlargers.

Best regards,

Robert