90/3.5 APO-Lanthar out of focus on R3A

[minoltist7]

I found that APO-Lanthar can't be focused correctly on my Bessa wide open.

How can I figure out, it is defective lens, or camera rangefinder is out of adjustment?
I tried it with 2 different adapters - same result.
So, when I focus on 2m distance (measured with tape), indicator on the lens barrel shows near 1,7 notch.
1,5m distance is real 1,3m
1m seems to be a close match.
Here are examples, it looks like a strong back focus shift


Before to send lens back to the seller, I need to figure out, is it really a lens defect?
Becouse it quite costly for me (I bought it from B&H in USA , and even replacement is free, I'll pay 30-40$ for the shipping twice)


For those who have 90/3.5 - can you look to the back of the lens please?
That notch (or tab) that pulls RF mechanism, is slightly raised above the lens thread in its extreme position (corresponding 1m)
- but on another lenses it doesn't .
Is it on all 90/3.5 like this?
it's hard to explain what I'm talking about, but if you have this lens in hand, you'll understand


p.s. my 35/2.5 focuses perfectly wide open with the same adapter (and even there is some degree of misfocus, it's hidden in DOF)

 

[ferider]

If the lens focuses OK at infinity, it's the camera not the lens.

The 35/2.5 is a bad comparison since the error you describe is completely covered by the DOF.

Sorry,

Roland.

 

[Roberto]

Hi,
I just tried on my Apo Lanthar and, at minimum distance, it is raised probably around 0.2/0.3mm, but it could also be 0.5, it's hard to tell..
It focuses perfectly at the minimum distance on my Bessa R, maybe it's the adapter?
I have one friend of mines that is not able to focus the 90/3.5 on the RD-1 with adapter at minimum distance..

Cheers,
Rob.

 

[minoltist7]

How can I tell that it is a badly aligned rangefinder and not a lens defect?
In both extreme positions (1m and infinity) lens should be perfectly in focus, regardless to what I see in VF, right?

 

[Roberto]

How can I tell that it is a badly aligned rangefinder and not a lens defect?
In both extreme positions (1m and infinity) lens should be perfectly in focus, regardless to what I see in VF, right?

I would say yes..
Rob.

 

[minoltist7]

I spent whole one roll for test (fortunately, cheap expired Konika)

F/3.5, 1m distance, scale focusing - sharp


F/3.5, 1,5m distance, scale focusing - sharp ( 2m - same result)



F/3.5, 1.5m distance, focused by RF. It shows "front-focus" (it is called like this?).
Focal point plane moved towards the camera for 2-3sm ( ~1-1,5 inches )


F/3.5, infinity:

It is sharp, but image not aligned in VF

But, Jupiter-8 matches 1,5m distance when focused by RF. It seems that RF error and lens error compensate each other?


So what are my options?
-Find a DIY repair manual
-Send it somewhere for service (there is no service for Bessas in whole Ukraine)
-Leave R3A "as is" for FSU lenses, and buy a second body for 50/90 ?

 

[Hates_]

You could try adjusting the RF patch as in the other thread.

 

[Roberto]

I spent whole one roll for test (fortunately, cheap expired Konika)

F/3.5, 1m distance, scale focusing - sharp


F/3.5, 1,5m distance, scale focusing - sharp ( 2m - same result)



F/3.5, 1.5m distance, focused by RF. It shows "front-focus" (it is called like this?).
Focal point plane moved towards the camera for 2-3sm ( ~1-1,5 inches )


F/3.5, infinity:

It is sharp, but image not aligned in VF

But, Jupiter-8 matches 1,5m distance when focused by RF. It seems that RF error and lens error compensate each other?


So what are my options?
-Find a DIY repair manual
-Send it somewhere for service (there is no service for Bessas in whole Ukraine)
-Leave R3A "as is" for FSU lenses, and buy a second body for 50/90 ?

So.. summarizing: the lens is OK, but the RF is OFF both at close distance and at infinity in respect to the lens.. moreover the RF is OK with FSU lenses.

Everything is saying that the RF in the camera is not aligned, I would suggest you to align it at infinity with a CV lens (not a FSU one..); I'm not sure whether the 90 is the best one to do it...

I noticed that it has a long throw in respect to other CV lenses and that has a very far infinity point, so.. if you use it to align at infinity use a cloud to do it.

With my Bessa R all of my CV lenses focus correctly at short distance wide open (21/4, 35/2.5, 90/3.5), but the 90/3.5 aligns the RF at a infinity point more far away in respect to the other 2 lenses.

My 2 cents...
Rob.

 

[minoltist7]

I noticed that it has a long throw in respect to other CV lenses and that has a very far infinity point, so.. if you use it to align at infinity use a cloud to do it.

With my Bessa R all of my CV lenses focus correctly at short distance wide open (21/4, 35/2.5, 90/3.5), but the 90/3.5 aligns the RF at a infinity point more far away in respect to the other 2 lenses.

I found that at infinity, non-coincidence of images in VF is more noticeable for 90/3.5, than for 35/2.5
I have no other lenses... probably the best lens for fine-tuning RF mechanism would be something like 50/1... oh, if someone could rent me a 'lux for a day 🙂