1960’s Kyoei W.Acall 35mm bug/feature

[maldaye]

Hi,

I bought an ebay Kyoei W.Acall 35mm in what appears to be good condition and fungus free.
However, there seems to be an odd thing happening.
The focus ring is tied to the aperture ring. If I move the aperture to f22 then the focus ring has full range.
However, if I put it to 3.5 it is locked.
The range of movement of the focus ring seems to depend on the aperture size.
Is this normal feature or do I need to get it repaired?
Thanks

[kansalliskala]

what mount?

[maldaye]

m42

https://www.ebay.com/itm/1960-s-Kyoei-W-Acall-35mm-f3-5-Camera-Lens-35319-RARE/143793047546

[visualopsins]

Not normal in my experience with other lenses.

[pdccameras]

That does sound strange. Also, the three knurled rings indicate this lens has a preset diaphragm control. This would limit the movement of the aperture, but should not affect focus. Do the aperture rings rotate when you focus?

Best

Paul

[maldaye]

If the black ring on top is set to 3.5 then the silver ring below doesn't move. If you move the black ring to 22 then the silver ring moves freely. I am not sure if the black ring does anything in of itself. However, the silver ring controls the aperture itself. No other part of the lens moves. Am I missing something?

[visualopsins]

[maldaye]

No other ring moves. Where is the focus ring?

[visualopsins]

[Alun Thomas]

If the focus ring won't move it could be gummed up with grease that has set hard. It should be repairable, but you need a fair degree of confidence in your mechanical skills.

[maldaye]

thanks for all the help. I got it working. The focus ring was stuck but after some *push* it started moving again and smoothly.

[Lightshow]

Ahhhh, presets, a brief moment in time of lens design development, between fully manual aperture and semi-auto(like cocking the hammer of a pistol) apertures.

Manual
Preset
Semi-auto stop down(only a handful of lenses had this flavour of auto aperture)
Automatic stop down
Automatic Exposure stop down (the camera chooses the aperture value)

3 ring presets, the function of the rings can be in any order depending on the lens.
First ring sets the pre-set aperture value, they typically have heavy detents to prevent accidental adjustments.
Second ring operates aperture, it is typically clickless(no detent).
Third ring operates the focus helicoid.

Another flavour of preset is the dual action preset aperture ring, these look very similar to a manual aperture ring, only they have a hidden function, typically you will pull the aperture ring towards the camera and rotate it to the preset value and release it, then the aperture ring will only have the aperture values between max aperture and the preset value, the aperture ring can/may have detents at standard values.

...So if your manual aperture lens won't stop down past a value, it might be a preset.

Since exposure meters in camera wasn't a thing till auto cameras, you would typically set the aperture for the general conditions(like sunny 16 rule) so you'd set the preset to f16 and bounce back and forth between wide open and the preset value, wide open for focusing and composing (the optical viewfinder is usually too dark when stopped down) and the preset value for the exposure, a very efficient system.

I however use the 3 ring preset lens a bit differently with my mirrorless cameras, I will use the clickless ring as the only aperture control(the preset set to full range or to my absolute expected limit), I don't usually use aperture for exposure, but mainly for DOF control, and to a lesser degree to control sharpness, this provides me with infinite control over DOF and lets me see actual DOF in real time and I can optimize it for the subject rather than picking the nearest aperture indexed value(f2.8, 2, 1,8, 1.4....), I can have f2.3 if the subject required it.

[kansalliskala]