Enlarging lens won't close beyond f16

[Mike Chalmers]

Hi @pentaxuser

Ifn my last post, the quote suggesting i pull lightly downwards on the aperture ring to move the pre-set aperture is what I did to solve. Once pulled down and rotated to the right, I was able to move between all apertures.

In Mike's final reply #24 he makes no mention of a switch which so I wonder what was stopping his getting beyond f16

So no it's not a switch, it's a pull and rotate movement of the aperture ring. But completely seperately to that, there is a switch on the rear side allowing smooth or click stop aperture changes.

I hope that clears things up. If yours has no switch, perhaps thats a difference in the 80mm?

Cheers

 

[pentaxuser]

Hi @pentaxuser

Ifn my last post, the quote suggesting i pull lightly downwards on the aperture ring to move the pre-set aperture is what I did to solve. Once pulled down and rotated to the right, I was able to move between all apertures.



So no it's not a switch, it's a pull and rotate movement of the aperture ring. But completely seperately to that, there is a switch on the rear side allowing smooth or click stop aperture changes.

I hope that clears things up. If yours has no switch, perhaps thats a difference in the 80mm?

Cheers

Thanks Mike. What I was getting at was that in my case with my 80mm lens there is no means of preventing me accessing the full range of fstops either by click each stop in the "up" position or smooth and stepless in the "down" position. There isn't as you say a switch in my case. In your case however there is a switch but this appears from your last sentence in your middle paragraph to be there for only switching between smooth and click stop and is not a switch that halts movement of the ring.

At the risk of appearing to be thick, can I confirm that this switch actually stops dead any movement on the aperture ring beyond the pre-set fstop which happened to be f16 in your case, when you discovered what you thought was a possible defect in the lens?

Thanks

pentaxuser

 

[Mike Chalmers]

No problem -

no, the switch allows movement between all apertures in both positions. It only changes from a “click” which lands precisely on stops to a smooth motion which allows the aperture to be open anywhere ie between stops.

it’s the aperture ring that you turn to change the aperture to lock - pulling this down and rotating it. This is what you should try if you want to prevent going beyond a certain aperture (though I’m not positive your lens will have this feature either)

best

 

[wiltw]

The pre-set aperture makes it possible to set a working aperture that can be put into operation by simply turning a ring to a stop after the picture has been composed and focused, and you just twist to go wide-open and twist back to go to your pre-set. According to one post, "The Rodenstock simply uses a pull down aperture ring to set it "

 

[Mike Chalmers]

The pre-set aperture makes it possible to set a working aperture that can be put into operation by simply turning a ring to a stop after the picture has been composed and focused.

Yeah, think someone mentioned that above. I have a switch on my durst to remove filters to compose, which I use - but I can see how this might come in handy too.

 

[AgX]

Reading all of this made me try my Rodenstock Rodagon 80mm f5.6 lens. In my case pulling it down allows a step-less movement of the aperture throughout its range and pushing it up gives a click stop aperture feature. However in my case the click stop can be clicked through the full range and there is no switch to prevent any movement.

Depending on time and FL there were at least 3 different versions of Rodenstock enlarging lenses concerning these features.
Moreover, a certain operation (pulling down the aperture ring) may have different effect.

 

[pentaxuser]

Thanks all.
Mike, my difficulty in understanding what you were saying stems for the fact that what I do to my lens sounds the same as yours initially but in fact you have a feature that I do not as AGX has pointed out. It is clear now. Thanks

pentaxuser