Help... 85% of photos out of focus/blurry on Mamiya 645pro 80mm f1.9

Rolleiflexible said:

Yes. Medium format requires a different approach from 35mm. DOF is much thinner, especially when shooting at wide apertures. (At f/4, it is a challenge to keep both eyes in focus in a MF portrait.) I almost never shoot with an aperture wider than f/5.6 -- if you miss focus by even a millimeter wide-open, it will ruin the image.

Focusing with a center spot before framing is a habit that you must break, *especially* if shooting medium format at wide apertures. Think about the geometry. The focal plane is basically perpendicular to the line of sight. When you focus with a center spot on a subject's eye, then rotate the camera to put the subject off-center, the focal point will land on the subject's ear. At f/4 this will be painfully obvious.

So, yes, my advice is to reinstall the screen without the center spot, and teach yourself how to see focus on the screen without the crutch of a center spot. It might not solve your problem. You still might have camera issues, even after reinstalling the original screen. But you will rule out user error and be a better photographer for it.

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Rick A said:

If you are able to remove the film back(or the insert) put some frosted cellophane tape (or waxed paper) across the film plane and open the shutter (raising the mirror) to project an image onto the tape. check focus at minimum distance (measured) to see if the image is in focus. Then lower the mirror and check the focus on the focus screen, do they match? If they match, repeat procedure at infinity. If the film plane and focus screen match, the issue is in the lens, if they don't agree, the issue is the mirror.

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Qiuhong said:

with screwing the little screw on the mirror stop, maybe I'll try that.

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reddesert said:

I am not sure that I followed all the results in the Updated post, but I strongly suggest testing with the original screen, eliminating the ebay screen and the split-image as a variable, and making sure you understand the amount and direction of any focus offset at both near and far distance before turning a single adjustment screw.

And if you do turn any screws, take careful notes on which ones and how many turns. It is often easy to make things worse and have difficulty iterating back to original settings.

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Qiuhong said:

Cool! will try that, also if I use a split image like the standard mamiya 645 focusing screen can I still use this same method without looking at the split image? that way I have both options?

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Qiuhong said:

This is super helpful! the plastic part did have hairline crack on it like in the video though it's all intact, I don't know how long it'll last, also the I found that the infinity focus is off too and the video explains it really well, thank you! Were you able to replace it yourself?

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