CZJ 35/2.4 Flektogon

Anu · Joined: 14 Apr 2009 Posts: 879

I have two copies of this lens - both auto and electric. I got the latter dirt cheap after the auto version and it (electric) seems fine, other than that there is one interesting feature: it stops down beyond f/22 - there are two more "clicks" (half a stop and a full stop I guess) available beyond the markings and the aperture blades do close down as well. Also, one can adjust the aperture smoothly - there are clicks, but one can also shoot with the aperture between full and half stops.

Is this normal bahaviour for this lens? Should be happy or expect the piece to break down soon?

PaulC · Joined: 23 Dec 2008 Posts: 2318

Mine doesn't do that. Have you counted the number of clicks from wide open to tight shut? Maybe someone has reassembled the lens with the aperture ring in slightly the wrong position so that your "f32" postion is really f22 and you are getting f2.4 halfway between f4 and f2.4. Set it at f4 and you should have three clicks until it is wide open.

Anu · Joined: 14 Apr 2009 Posts: 879

PaulC · Joined: 23 Dec 2008 Posts: 2318

Very mysterious as it is meant to be an identical lens to the Auto. I also have both versions and it was my electric I was comparing it with - so not all electrics have this.

sichko · Joined: 20 Jun 2008 Posts: 2475 Location: South West UK

It could be a DIY modification. I'm not sure how the "click-stop" mechanism works on this lens but on many others a ball bearing sit in a (spring loaded ?) hemispherical cavity in the body of the lens and is held in by contact with the inner surface of the aperture ring. Indents on this surface provide the different click-stops. It might be possible to file two extra indents for the extra stops - it's certainly been done with other lenses.

PaulC · Joined: 23 Dec 2008 Posts: 2318

Well, there must be some reason for it. I wouldn't think the extra stop is any benefit since the image quality will suffer and the DoF on 35mm is enormous even at normal apertures.

There doesn't seem to be any reason to suppose that it means something will go wrong with the lens soon.

Anu · Joined: 14 Apr 2009 Posts: 879

Sven · Expire: 2011-12-29

On my Flek I can turn one click passed 22, but it's in the correct position at 2.4.
The extra click doesn't actually seem to do anything to the Iris. The opening seems to stay the same.

pirius · Joined: 28 May 2009 Posts: 133 Location: SoFla

Same here - I can click once past 22, but it does actually make the opening a little bit smaller (almost like a pinhole at that point). But if I click back to 22 it does not open up, not until I get to 16.