Adjusting focus screen on Mamiya 645 Super

cerber0s

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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

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First step is to have the lens focus infinity correctly onto the film. This requires an autocollimator. Then, adjust the focus screen as needed.
 
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cerber0s

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ic-racer said:
First step is to have the lens focus infinity correctly onto the film. This requires an autocollimator. Then, adjust the focus screen as needed.
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Yes, but either way I need to know how to get to the focus screen adjustment screws.
 

ic-racer

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cerber0s said:
Yes, but either way I need to know how to get to the focus screen adjustment screws.
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I guess I was considering the possibility that no one has found the screws previously and they might be still maintain the factory setting.
 
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cerber0s

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ic-racer said:
I guess I was considering the possibility that no one has found the screws previously and they might be still maintain the factory setting.
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There’s probably something I don’t understand here. Would that change anything? The focus still needs adjusting, right?
 

monopix

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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/
 
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cerber0s

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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

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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.
 
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cerber0s

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I sent it away for repair, and you are correct, the mirror stop needed adjusting. The problem is that the adjustment screw is worn out, so adjustment was near impossible. This is a shame since the camera is otherwise in mint condition and 100% functional.

Now I’m not sure what to do. I either find another Super body, and keep this one for spare parts, or I find a Pro body instead. If I go for a Pro, will my power winder, AE prism finder, waist level finder, and all my filmbacks I have for the Super also work for a Pro body?
 

MattKing

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cerber0s said:
If I go for a Pro, will my power winder, AE prism finder, waist level finder, and all my filmbacks I have for the Super also work for a Pro body?
Click to expand...

Yes to the finders and film backs (and inserts of course).
Probably WRT the winder.
By the way, there are 3D printed replacement mirror stops out there - at least for the Pro and Pro Tl, so I would expect for the Super.
 
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cerber0s

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MattKing said:
Yes to the finders and film backs (and inserts of course).
Probably WRT the winder.
By the way, there are 3D printed replacement mirror stops out there - at least for the Pro and Pro Tl, so I would expect for the Super.
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Thank you!

Yes, it has a 3D printed mirror stop. The problem is the adjustment screw for it, it's completely worn out and can't be turned (slot is gone). Such a stupid reason to put it on a shelf.
 

monopix

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cerber0s said:
Thank you!

Yes, it has a 3D printed mirror stop. The problem is the adjustment screw for it, it's completely worn out and can't be turned (slot is gone). Such a stupid reason to put it on a shelf.
Click to expand...

So are you saying whoever you sent it to couldn't repair it? Sounds like someone to avoid if they can't remove a damaged screw and find a replacement. If necessary, the whole stop can be replaced with another. Shouldn't be a major problem. Send it to someone who knows what they are doing.
 
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cerber0s

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It’s not that he couldn’t, he didn’t have the spare parts. Getting the spares would include getting a donor body, which means that it’ll be cheaper for me to just find another body to use.
 

koraks

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I'd replace or modify that 3D printed mirror stop so that the focus is correct within the range that the damaged adjustment screw allows. It's not going to win any beauty pageant that way, but it'll work.
 
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cerber0s

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koraks said:
I'd replace or modify that 3D printed mirror stop so that the focus is correct within the range that the damaged adjustment screw allows. It's not going to win any beauty pageant that way, but it'll work.
Click to expand...

Yes, I’ve bern toying with the idea of either taking some material off the stop, or adding some, depending on which way it needs to go.
 
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cerber0s

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monopix said:
But you can buy another 3d printed one for little money.
Click to expand...

It’s not the mirror stop that’s broken, it’s the adjustment screw. The slot in the screw is completely worn out. Replacing the stop won’t help as the new one can’t be adjusted either. If I’m lucky I can find a screw somewhere that fits, I have a bunch of donor cameras of various makes and models.
 
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cerber0s

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I got the camera back from tye tech today and took the mirror stop out myself. It looks like whoever replaced it last put the adjustment screw on backwards. I’ve turned it around but struggle getting the stop back on, the spring is giving me trouble. Has anyone done this?
 
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cerber0s

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Never mind, I managed. The adjustment screw is too short though, probably the readon it was reversed. At least now I inow that I can fix it.
 
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cerber0s

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It’s mostly sorted now! I did a deep dive in the parts bin and found the perfect screw in a broken lens. Now all I have to do is fine tune the focus, which is at least possible now.
 
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