I find the viewfinder one of the negatives about the camera. It would drive you to drink.
Anyway, what you've first got to determine is that your camera is perfectly horizontal on the tripod. Use a spirit level if you must.
Now you have a base line. Attach a lens and try to compose for the corners of a focus chart all the way around.
Do your best, by wiggling, cajoling, manipulating, tweaking, loosening silver arms, cursing in Russian, whatever it takes to get close to perfect.
Open the camera door and inch the mirror so that you can clear the aperture.
Put a piece of scotch tape across the aperture so that it acts like a ground glass.
You should now see the image of the chart on the tape...use the translucent tape, not the clear stuff.
Go back to the eyepiece and inch the camera for reflex viewing and look in.
Both images should match.
Even if your viewfinder image is slightly dutch-angle or cut-off, you will know that THE FILM is getting a full horizontal image.
This will, at least, enable you to shoot with a little more confidence for now.
Ultimately you will need to see either a good camera-repairman, or a shrink, Cheers.
Sorry, May be. i understand do not full, but, i think, you told about complex and a mistaken technology.
If you think, what Konvas viewfinder very complex at adjust, i wish know your opinion about Arri viewfinder adjusting.
Do not need "perfectly horizontal on the tripod".
This is procedure need for adjust of disanamoprhic viewfinders only.
Spherical viewfinders adjust about a boders of ground class.
The viewfinder of all Konvas cameras - very reliable, simply, high bright and high sharpness.
If you have any problem with viewfinder, need repair at service lab only.
The ground glass of Konvas cameras set on one surface of glass prism.
The prism set inside prism holder and fix on body of camera by two scriws and two pins.
The body of prism do not move at any case.
The next - body of viewfinder track with two mirrors.
If the body of camera do not droping, the body with mirrors will OK too.
If the body of mirrors displaced , need repair at service lab only with " sample viewfinder ".
The next device - viewfinder.
The viewfinder have adjustable main mirror inside with big screw for fix of position of mirror.
This is device possible adjust with special tools only.
If you do not have special tools, you will have a some " headache" to adjust of position of mirror correct.
The next - mirror inside viewfinder, This is device set hard and can need very small adjusting.
The viewfinder have mechanism of change mask's position.
May be, you have problem with mask's control ?
The next - mechanism of focusing of viewfinder and mechanism of control of viewfinder blades.
Any case, if you have more question or need help , can send me PM.
Konvas viewfinder adjustable device and good maintainable.