Color Heliar 75/2.5 Focus Adjustment

[Uwe_Nds]

My Color Heliar 75/2.5 showed some backfocus on the M8, so - being still under warranty - I sent it to Voigtländer to have it adjusted.
It came back with a note telling me that the lens is within manufacturer's tolerances.
So I decided to tackle the lens myself and I succeeded.
This instruction does not cover adjustment of the rangefinder cam - that was perfect on my lens.


Actually, the Color Heliar 75/2.5 is much easier to adjust than the Ultron 35/1.7. Still, I do not take any responsibility if you are messing up your lens.


Tools required:
- Phillips screwdriver
- (small slotted screwdriver)
- nail varnish (your favourite colour ;-) )

 

[Uwe_Nds]

1. Unscrew the hood and remove the front name ring. I used a small slotted screwdriver which I put in one of the engraved letters (e.g. the vertical part of the "E"), but make sure you do not scratch the front lens.


2. Below the name ring you will find six screws: three black (small) ones and three chrome (long) ones. Remove the three chrome screws and lift off the front lens group together with the aperture dial. Note the tab controlling the aperture - this sits in a recess in the aperture dial.

 

[Uwe_Nds]

3. The position of the "optical module" is not adjusted via shims, but by turning a ring with three long slots. Loosen (but not remove!) the three screws locking the adjustment ring and adjust focus by slightly moving the optical unit. You may only need very slight movements - easy to check with the M8, not so easy with a film camera.
After you adjusted the focus, tighten the screws and lock them with a bit of nail varnish.

 

[Uwe_Nds]

4. Re-install the front lens group with the aperture ring. Make sure that the tab controlling the aperture goes into the recess in the aperture ring.


5. Re-install the three chrome screws and lock with a bit of nail varnish.


6. Re-install the front name ring and screw on the hood.


7. Done. Your Heliar should now focus like this:

 

[Uwe_Nds]

Cheers,
Uwe

 

[lemalk]

Thanks, Uwe.
I am having a similar issue on a 28mm 1.9 Ultron.
I wonder if the internal build is similar to the Heliar 75mm to adjust focus.

Any insight before I have a go at it?

 

[Uwe_Nds]

I have no experience with the 28/1.9, but from what I read its internal build is similar to the 35/1.7.

On the Ultron 35, the rangefinder cam gets displaced when you change the position of the optical module, therefore you have to take off the chrome lens mounting ring and mark the position of the 3-slotted ring relative to the RF-cam. After adusting focus, you will have to reposition the 3-slotted ring on the back of the lens, otherwise the RF-cam will be off.

Hope that was understandable.

Cheers,
Uwe

 

[lemalk]

Yes - I understand. Thanks so much.

 

[XFer]

Hello, sorry to dig out an old thread, but I noticed that my Color Heliar 75/2.5 frontfocuses.

I'm trying to follow the instructions Uwe wrote, but I'm stuck at point 1!:

1. Unscrew the hood and remove the front name ring. I used a small slotted screwdriver which I put in one of the engraved letters

I really can't figure how to remove the front name ring. :-(
I understand that, with the screwdriver forcing at the edge of an engraved letter, one has to force the ring to unscrew, right?
Mine does not move one bit, I'm perplexed. :-(