Mamiya 645 AFDii Focus Problems

One thing to add - 645 AFDii has a minimum focusing range of 3.3ft and I was well beyond that - about 6 feet away.

fotonomadic said:

One thing to add - 645 AFDii has a minimum focusing range of 3.3ft and I was well beyond that - about 6 feet away.

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Well, the Mamiya 150mm f/2.8 IF D lens has a minimum focusing range of 3.3ft, not the camera itself. Each lens may be different.

The autofocus on a Mamiya 645 AFDii is loud and tends to hunt back and forth, but eventually should focus accurately.

I think you should drop the focusing screen down, and then press it back up, to make sure it is seated correctly. The focus could be off by a foot when the focusing screen is off by a millimeter. However, the autofocus sensor is below the mirror, and doesn't use the focusing screen. So, also check that the mirror is not obstructed.

Otherwise, the lens or the back is out of alignment.




--Steve.

fotonomadic said:

Hi everybody!

Brand new here, so I hope this is the right place to post questions like this.

I have a 645 AFDii that I just started using again that I've been having major focus issues with.

The AF seems to be virtually useless - unless it's malfunctioning. I've switched it from standard to spot focus in the custom functions but nothing changes, it's just way way off all the time.

Even when I manually focus, the focus is always off by several inches. I'm using a split-type focusing screen.

I'm farsighted, but I had my contacts in when I shot some test images the other day. I could see the lines on the split-screen lined up perfectly in the prism finder but the focus is way way off in the image. I focused on her eyebrow and the rug about a foot in front of her is what is actually the sharpest.

Anybody have any experience with Mamiya having focus issues like this? I had hoped to mainly manually focus, but even the AF is totally off, too, so starting to worry that the issue is in the camera and/or lens versus me just being blind as a bat. With my contacts in it shouldn't be a problem.

Any suggestions would be appreciated. Thanks so much!

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Lovely, if misfocused, image!

What you need to determine is whether the autofocus is providing low accuracy or low precision. That is, if you autofocus many times in a row (resetting the focus in between) is the focus consistently wrong or inconsistently wrong?

You say "the focus is always off by several inches." but you don't say if it's always off by several inches the same direction.

For example if you test it by trying to focus on an apple sitting on a counter, and focus ten times in a row, and all ten end up focused 2" behind the apple then the focus is, of course, wrong, but it is consistently wrong (that is high precision, low accuracy). If, instead, the focus is sporadic, sometimes in front of the apple a little, sometimes in front of the apple a lot, sometimes behind the apple a little, sometimes behind the apple a lot, and sometimes perfectly focused, then the focus is inconsistently wrong (low precision, high accuracy).

A) If it is consistently wrong then the autofocus is working well, it's just out of calibration with the image plane (the film or digital sensor). Either it or the film back or digital back needs service to bring the focus plane and image plane into proper alignment/calibration. If you have more than one film back or more than one digital back, or can borrow/rent one from a dealer then you could narrow in on which component is out of calibration; if changing film/digital backs resolves the issue then that component is likely the culprit, but if changing film/digital backs does not resolve the issue then its likely the body that is the culprit.

B) If it is inconsistently wrong then you are simply experiencing that the AFD2 has poor autofocus compared to modern cameras, and there is only so much that can be done to help (practicing with the focus, using the "double tap" method of using the AF button once to get the focus close and a second time to fine tune it, learning the "lean" method for focusing not-in-the-center-of-the-image since this is a center-only focus camera).

In your post is a hint as to which issue you are seeing. You report that when focusing manually the recorded focus is still wrong. That implies the issue is likely (A) – that is, the body or film/digital back is out of whack and needs service. However, that's not definitive, in and of itself.

By the way, more recent iterations of the Mamiya/Phase platform, like the Phase One XF, have significantly improved autofocus; we have an office in Culver City if you ever want to come play with one.

This camera has interchangeable backs, so if your manual focus results in the same front focus as your auto focus (ie: manual focus agrees with auto focus), then as Doug said, you digital back's image sensor plane is out.

The supplied image appears to be front focused, so the digital back's image plane is further away than the screen. Try remounting the back securely, check that it's not missing it's IR cover glass, or anything that puts the sensor too far away. If that checks out, then as Doug said, it need calibration.

Thanks so much, guys, for the info.

I did a manual focus test on another 645 (non AF) and the problem turns out to be...my eyes!

I'm farsighted, I wear contacts to correct the issue but it looks like I am pretty much incapable of manually focusing a camera anymore. I ran several rolls and used a pretty systematic approach, shooting objects in controlled conditions at different apertures and having another photographer shoot the same objects with my camera at the same time (switching back and forth) under the same circumstances with me. As far as the manual focus issues go, it's my eyes.

There's a diopter - I tested using that (without contacts) but unfortunately - no dice there, either.

The AF on the camera can be switched in custom settings to "spot" and once I did that, the out of focus frames (using the clunky, clumsy AF) reduced pretty drastically.

I've been shooting DSLRs with 40+ autofocus points and gotten very spoiled. This center-weighted AF on these older cameras takes some getting used to, for sure.

Come to the conclusion that I am doomed to only every use autofocus cameras - a huge bummer, but a least now I know. The diopter goes up to +3 and I'm a +2.75 so not sure why that didn't work - removed and reinstalled the view finder and made sure it was clicked tightly in place but nothing changed. But then using AF the images were much sharper, so it seems the lens and back are okay on that score.

Anyway, thanks very much for all the very helpful advice!

Just an idea ...

I have not shot with your particular Mamiya, but have owned and operated a RB67 and RZ67, the RZ with a digital back.
I too wear glasses and have no issues with focus unless I am wearing my contact lenses. Try manually focusing with glasses if you have them.

Best to you,
Darr

If you wear eyeglasses, I have found that the diopter correction is crucial to determine correct focusing using manual focus lenses.