Mamiya 645 super Help!

[monjue]

With the mirror stop broken or removed,

No, you would not pass infinity if the mirror is at the bottom of the mirror box as the mirror would be at an angle greater than 45 degrees. If the mirror was at an angle less than 45 degrees then you would pass through infinity.

Mirror stop is removed. While lowering the mirror from top to very bottom, it never reaches infinity. That's exactly my issue! Its super strange.

 

[monjue]

@monjue on Hasselblads what you're describing can happen if the focusing screen is installed upside down.

ok i seem to have fixed the issue. The glass that sits above the focusing screen has what looks like a thin removable plastic frame. This was actually installed below the clear glass and not above it. Swapping this round seems to have fixed the problem. I can now reach and pass infinity using the adjustment screw. However!! I have a new problem. I calibrated Infinity using the 55mm lens, but when i swap it over to the 80mm, infinity is off.. switching back to the 55mm and all is good again. So now i dont know what to do about this issue!

 

[MattKing]

Is there any chance that the problem is with the position of the focusing screen?

ok i seem to have fixed the issue. The glass that sits above the focusing screen has what looks like a thin removable plastic frame. This was actually installed below the clear glass and not above it. Swapping this round seems to have fixed the problem

You are welcome .

However!! I have a new problem. I calibrated Infinity using the 55mm lens, but when i swap it over to the 80mm, infinity is off.. switching back to the 55mm and all is good again. So now i dont know what to do about this issue!

Are you using the split image focusing aid or are you using the ground glass to do your "calibration"?

 

[monjue]

You are welcome .

Are you using the split image focusing aid or are you using the ground glass to do your "calibration"?

Im using split image focusing aid by looking at the ground glass through an eye loupe. 55mm split is lined up perfectly (that's the lens i calibrated with) .. 80mm is off quite noticeably and i have a 150mm that's also off but hardly noticeable.

 

[shutterfinger]

Set up infinity with the 150 then check the 80 and 55.

 

[Neil Grant]

...I think the failure of the plastic mirror stop in the later Mamiya 645's is just an example of 'engineering down'. A similar problem is unknown in the original metal bodied 645 cameras, with cameras failing before the mirror stop. Perhaps in Mamiya's judgement there was little point in making an excessively durable part and they could save some cost by designing a cheaper one.

 

[MattKing]

Don't use the split image focusing aid - use the ground glass.

 

[monjue]

Don't use the split image focusing aid - use the ground glass.

So the ground glass is the glass around the split/circle? sorry.

 

[MattKing]

So the ground glass is the glass around the split/circle? sorry.

Yes - outside that circle.
In a perfect world, the split image focusing aid will work well and match the ground glass area, but it is that ground glass area that most accurately reflects the focus behavior of the viewing system.
By the way, what viewing system/finder are you using when you actually take photos?

 

[monjue]

Thanks all for the advice/support. issue seems to be still present. im going to leave it to a repair shop to figure out. thanks again.