Adjusting focus screen on Mamiya 645 Super

[cerber0s]

My 645 Super is off focus. I’ve tested with several lenses, and it’s most noticeable with wide angle lenses at infinity. When the when everything looks in focus in the viewfinder, focusing on an object far away, the scale on the lenses are at 3 meters. Images come out put of focus as well.

The mirror stop is fine.

I’d like to adjust the focusing screen, and I can get to the adjustment screws on the right side, but not the ones on the left side (under the contacts for the viewfinder). The plate with the contacts won’t come off, and I’m guessing it’s attached to a flat cable or something like that. Does anyone know how to remove the contact plate?

 

[ic-racer]

First step is to have the lens focus infinity correctly onto the film. This requires an autocollimator. Then, adjust the focus screen as needed.

 

[cerber0s]

First step is to have the lens focus infinity correctly onto the film. This requires an autocollimator. Then, adjust the focus screen as needed.

Yes, but either way I need to know how to get to the focus screen adjustment screws.

 

[ic-racer]

Yes, but either way I need to know how to get to the focus screen adjustment screws.

I guess I was considering the possibility that no one has found the screws previously and they might be still maintain the factory setting.

 

[cerber0s]

I guess I was considering the possibility that no one has found the screws previously and they might be still maintain the factory setting.

There’s probably something I don’t understand here. Would that change anything? The focus still needs adjusting, right?

 

[monopix]

If I understand correctly. you're saying when something at infinity is in focus on the focus screen, the lenses are focussed at 3m. Yes? That's a big error. For that to be so, something is broken. I wouldn't be trying to adjust anything until I knew what the cause was. You say the mirror stop is good, how do you know? The mirror stop is a very common problem on these (I've owned several). Is this a camera you've just acquired? Do you know the history? Has it ever been correct while in your possession? Could be the mirror stop broke and someone has fixed it incorrectly.

This previous thread might be of interest: https://www.photrio.com/forum/threads/mamiya-645-super-help.186927/

 

[cerber0s]

If I understand correctly. you're saying when something at infinity is in focus on the focus screen, the lenses are focussed at 3m. Yes? That's a big error. For that to be so, something is broken. I wouldn't be trying to adjust anything until I knew what the cause was. You say the mirror stop is good, how do you know? The mirror stop is a very common problem on these (I've owned several). Is this a camera you've just acquired? Do you know the history? Has it ever been correct while in your possession? Could be the mirror stop broke and someone has fixed it incorrectly.

This previous thread might be of interest: https://www.photrio.com/forum/threads/mamiya-645-super-help.186927/

Yes, you understood that correctly, and yes, it's a big error.

The mirror stop is good, It was professionally replaced just before I bought the camera around a year ago. It was replaces using a 3D printed part, and I've pushed it down with my finger to make sure it's in one piece, which it is. Something was obviously not done properly though.

 

[monopix]

Yes, you understood that correctly, and yes, it's a big error.

The mirror stop is good, It was professionally replaced just before I bought the camera around a year ago. It was replaces using a 3D printed part, and I've pushed it down with my finger to make sure it's in one piece, which it is. Something was obviously not done properly though.

It's much more likely the mirror stop needs adjustment than the focus screen. Just because it was 'professionally' replaced doesn't mean it was done properly. I've just had a camera sent to me for repair that had the mirror 'professionally' replaced. Well they did, but they paid no attention to if the focus was correct afterwards. I would try adjusting the mirror stop screw before messing with the focus screen.