Rolleiflex viewing and taking lens focus alignment

[yashima]

Hi everyone,

I notice my Rolleiflex viewing lens (the Heidosmat) has some fungal growth in the front element. I think I can unscrew it out and clean it relatively easily. However I'm fearful about it getting out of alignment with the taking lens (Planar).

What can I do to make sure the lenses are in focus alignment?

Thank you.

 

[Dan Daniel]

Select a distant object and check the focus of the viewing lens before removal- does it come into focus at infinity, go a bit beyond, or not quite reach it? If if focus is aligned already as you shoot, simply install the lens and go for the same focus as before removal.

Ideally you collimate the taking lens, which means resetting the infinity stop of the focus knob. Then you set the viewing lens to match. If focus seems to be aligned already this isn't absoltely necessary.

 

[anfenglin]

I have a spare glass focusing screen from an old Rolleicord, I use that to check infinity in the cameras I repair.
I set the shutter to B or ideally T and hold the screen matte side away from me onto the guiding rails of the camera where the film should be.
I set the camera to infinity, open the shutter and check wether the lens is at infinity using my collimation trees outside the bathroom window which are at least 200m away.
If that is ok I can go to checking the viewing lens.

In the Rolleicord III I once had I noticed that the front plate had to be taken off to take the lens block out because there is a grub screw holding it.
Turning the lens just like that didn't work. Be careful not to lose the tiny shims in the shafts holding the screws which hold the front plate.

Depending of course on how bad the fungus is, I'd just leave it alone. If it is a small spot, taking the camera out shooting i bright sunlight eventually kills the fungus anyway, but you can then still see the mycels.
Of course, cleaning it away would take care of that problem, too, but if you are not confident in fiddling with a Rolleiflex I'd leave it.

 

[yashima]

I have a spare glass focusing screen from an old Rolleicord, I use that to check infinity in the cameras I repair.
I set the shutter to B or ideally T and hold the screen matte side away from me onto the guiding rails of the camera where the film should be.
I set the camera to infinity, open the shutter and check wether the lens is at infinity using my collimation trees outside the bathroom window which are at least 200m away.
If that is ok I can go to checking the viewing lens.

In the Rolleicord III I once had I noticed that the front plate had to be taken off to take the lens block out because there is a grub screw holding it.
Turning the lens just like that didn't work. Be careful not to lose the tiny shims in the shafts holding the screws which hold the front plate.

Depending of course on how bad the fungus is, I'd just leave it alone. If it is a small spot, taking the camera out shooting i bright sunlight eventually kills the fungus anyway, but you can then still see the mycels.
Of course, cleaning it away would take care of that problem, too, but if you are not confident in fiddling with a Rolleiflex I'd leave it.

Thank you. I think using ground glass at film plane is probably the best idea.

I was able to remove the viewing lens unit relatively easy (just unscrewed it out of the upper screw mount).

However at the back on the unit there is a ring, and I'm not sure what it is used for, or what position it should be. Anyone recognise this please?

Here is a photo of it:

 

[Dan Daniel]

The ring is the a retaining/tightening ring. If you look inside the opening where the lens goes you will see a matching beveled surface on the mounting flange. After the lens is screwed in to the proper position, this ring will be tightened down to hold it in place. If this hasn't moved on removal and you don't move it in your work and the focus was set properly before removal, simply screw the lens unit back in until this ring stops it and you'll bepretty darn close to proper focus.

 

[yashima]

The ring is the a retaining/tightening ring. If you look inside the opening where the lens goes you will see a matching beveled surface on the mounting flange. After the lens is screwed in to the proper position, this ring will be tightened down to hold it in place. If this hasn't moved on removal and you don't move it in your work and the focus was set properly before removal, simply screw the lens unit back in until this ring stops it and you'll bepretty darn close to proper focus.

Hi Dan,

Thank you very much, I think I vaguely understand how it works. I don't see a way I can tighten it with the way I'm assembling the lens, however I imagine I can tighten it if I remove the whole front panel assembly? (I'm still abit confused to be honest. Because the way I understand retaining ring, they should sit behind a panel to secure the lens into the panel. Here I can remove the retaining ring with the lens unit).

This retaining ring is quite loose, so its quite difficult to make sure it doesn't move at all. What I'm trying to do to ignore this problem is as followed:

1. I mark the position and number of turns when removing the viewing lens, and make sure when I assembly it back, it goes back to the previous position
2. fine tune using ground glass on taking lens film plane.

Would that work even though I dont keep the position of the retaining ring?


Thank you.

 

[Dan Daniel]

Yep, that ill be a problem to tighten it properly without the lens shroud removed (the notches on the outer edge of the ring are for a spanner wrench; you hold the lens still, tighten the ring, and the vertical force on the threads holds it in place). If you could get it out, though, that points to it not being tightened very well to begin with. Maybe someone has ideas? Medium thread lock?

Using ground glass on the film plane is for checking focus on the taking lens only. You will need to remove the cover on the focus knob and loosen the retaining nut in order to change the infinity focus of the taking lens. To be clear, you set infinity on the taking lens by moving the lens board, then set the viewing lens by screwing it in or out. Anyway, unless you are planning to change the overall/taking lens focus, you don't need to do anything with the film plane.Assume that the taking lens focuses properly.Use the focusing screen and set the viewing lens for infinity focus.

 

[yashima]

Yep, that ill be a problem to tighten it properly without the lens shroud removed (the notches on the outer edge of the ring are for a spanner wrench; you hold the lens still, tighten the ring, and the vertical force on the threads holds it in place). If you could get it out, though, that points to it not being tightened very well to begin with. Maybe someone has ideas? Medium thread lock?

Using ground glass on the film plane is for checking focus on the taking lens only. You will need to remove the cover on the focus knob and loosen the retaining nut in order to change the infinity focus of the taking lens. To be clear, you set infinity on the taking lens by moving the lens board, then set the viewing lens by screwing it in or out. Anyway, unless you are planning to change the overall/taking lens focus, you don't need to do anything with the film plane.Assume that the taking lens focuses properly.Use the focusing screen and set the viewing lens for infinity focus.

Now you said that, I have doubt whether we are supposed to be able to unscrew the lens unit from the front or not. It seems to be not the proper way to do it(?). But I have done that already .. When I screw it back in, with the same number of turns as when I removed it, its hold quite securely in place, so I guess that's at least acceptable.

Before the repair, both lens can focus well at infinity, and at agreement. My main concern now is for the viewing lens and taking lens to align. Do I only need to make sure the viewing lens can now focus at inifinity? Or should I also check focus at close distance for both lenses (using ground glass for taking lens) and make sure they agree?


Thank you.

 

[shutterfinger]

Set the taking lens to infinity at the film plane then without moving the camera (camera on a tripod) screw in the viewing lens until the image on the view screen matches the taking lens.
Each turn of the view lens is one thread on the lens barrel. You can count either the peaks or valleys. To help ensure the lens does not move put a band of clear nail polish on the threads just prior to installing at the number of turns (peaks or valleys from the end) and screw the lens into place. The nail polish will act like a thread locker and is easy to remove if needed in the future.