Difficulty focusing the RZ

[2F/2F]

Hello,

I finally got a Mamiya 67 of my own a few months back. I knew I loved RBs from using borrowed ones, I wanted one for years, and finally got this one from an APUG classified ad. I have shot about 15 rolls so far, and I love the thing.

However, I miss focus with this camera way more than I do with any other camera. It is not by much when it happens, and it always ends up being focused on something closer to me than I want in focus. I always have used the magnifier to focus. The lens is the brightest one available for the camera, so that should not be an issue.

The diopter on the WLF magnifier is marked -1.5. First of all, just in case I am frickin' stupid, I want to double check with you all to make sure that this is not made for eyeglass wearers. Heh heh.

Then, I want to find out what magnification levels you all find the best for critical focusing. I am tempted to go for the one that gives max magnification. I imagine that the more magnification you use, the farther you get from being able to see the entire composition through the magnifier. This is not a huge issue, however. Critical focus is more important to me. I can flip down the magnifier if I want to fine tune the composition. Sometimes too much magnification can actually make it harder to focus, however, based on my experience shooting view cameras, so I want to hear experiences with the different magnification levels.

I have a plain screen with a plain round bright center circle. I like it plain in the middle, but do you think a different screen would help me out?

What I am really dreading is the possibility that this could be a film flatness issue. Everything on the back end seems to fit snugly and be in good condition, however.

 

[Nick Zentena]

What steps are you taking to focus?

Focus without the magnifier.
Flip down to fine focus.
Check DOF.

You mention being focused on something other then the subject which makes me wonder :confused:

 

[2F/2F]

What steps are you taking to focus?

Focus without the magnifier.
Flip down to fine focus.
Check DOF.

You mention being focused on something other then the subject which makes me wonder :confused:

Hi, Nick. Thanks for writing.

I think the part that confused you was when I said that the shots I missed were always focused closer than the subject. For instance, once I focused on someone's eye, but their bangs were the part of the print that was *tack* sharp. This one was in a close focus situation, only stopped down 1.5 stops, so I figured I just screwed up a little. Another time I focused halfway into a diagonal field of text on a plaque. Yet on the print, only the left side of the text was *tack* sharp. This one was from 10 feet away, so I became more suspect. When I miss on this camera, it is always focused closer than I thought it was on the screen.

I use the WLF without magnifier to get a composition, and then the magnifier to focus and possibly make slight adjustments to the composition. I have never really used this camera in a situation in which I want extensive D of F, so I have only used the D of F preview to check how the out of focus areas are being rendered.

 

[catem]

The standard diopter for the RZ is -1.5

I have the focussing screen E, the Rangefinder Spot/Microprism, which is definitely easier to focus, as well as the standard Matte. The matte screen is nice if you really don't want anything obstructing your view but in all honesty I've never found this an issue with the screen E. And it's vital if you want to focus in any sort of hurry at all. I use the split screen all the time now.

 

[L Gebhardt]

Lay a ruler flat on the floor or a desk. Shoot on a number in the middle (say 6) and remember what it was. Do this wide open and on a tripod. Develop the film and see what number actually comes out in focus. On some cameras you can do the focus step and then flip up the mirror and put a ground glass at the film plane and check with a loupe. I haven't tried this on the RZ, so I don't know if it would work. If the focus isn't dead on you should be able to have the mirror adjusted, or maybe shim the focus screen. Also check that the screen is installed properly. If it is upside down focus will be off.

 

[archphoto]

I agree with you, shoot at wide open, forget the bit of softness.

Peter

 

[paul ron]

Does this happen with all your other lenses as well?

A split image screen may be what you need.

Although there is a posability another origianl screen was used in that camera n when it was sold to you the screen was replaced with the plain one you have.

Now the complication there may be an adjustment issue. The newer screens have fresnel lenses n a GG layer or the mount was thicker. So if the camera was focused for that one n now you are using a single layered screen, a thinner mount, it may need to be readjusted to focus on the film plane again.

The solution is to try a focusing check of the film plane. Put a ground glass on the film plane, focus the camera on a well lit target using the view screen n a loupe, then check the GG on the film plane with the loupe to see if it razor sharp.

If you notice on all 4 sides of the view screen there are large brass screws? Those are the adjusters. Mark each screw with a scribe line on a near by edge of the spring as an indicator to their location so if you turn it CW 1/2 turn you can make the same 1/2 turn exactly equal to each. Also it will be easier to undo your 1/2 turns if that wasn't the correct direction of compensation.

*Don't try adjsuting the mirror... it's fixed n will crack if you mess with it.

If you feel you can't do this, then take it to a shop n they can focus your camera properly for you.

 

[PVia]

Even Annie L mentions how hard it is to focus the RZ, in her new book...

It's definitely a challenge to get it right at wide apertures, especially the closer you are. But try the ruler test (above) on a tripod.

Were you using a tripod for the shots you mention in the original post?

 

[2F/2F]

Even Annie L mentions how hard it is to focus the RZ, in her new book...

It's definitely a challenge to get it right at wide apertures, especially the closer you are. But try the ruler test (above) on a tripod.

Were you using a tripod for the shots you mention in the original post?

Hi,

Thanks for the info, all. I will try the ruler test, which was my next step anyhow. I will try a Polaroid first, see how it looks, then use film. I don't have a small ground glass on hand to check that way.

Yes, I have used the camera on a tripod every time this has happened. I have pulled off successful hand held shots as well, but they were at f/8 to f/16, and focused rather far away, so showed no problems.

BTW, I am using the 110 lens. I have a 250 as well, but it needs some work.

 

[2F/2F]

Did the ruler test on Polaroid.

PERFECT results with the bellows within a few mm of being FULLY extended.

If there is a problem, it is me or the film back. Next, I will repeat the test using each film back and see what happens.

 

[bluedog]

I also have a similar problem in focusing my RZ. This mainly occurs ffor subjects in 1 to 3 metre range. I have a -2.0 diopter that came with the camera. I am shortsighted so this isn't too bad for mid to distant subjects. However for close subjects I don't need the correction. I always use the magnifer to focus for the final focus as the screen isn't that bright and it is a bit hard to tell if the image is focused or not.

 

[2F/2F]

I may have figured it out. I had been using a 220 insert in a 120 back. It seems to me that the back itself should be able to take any insert, however a few folks her on APUG have said that the back must match the insert. I will have to dig up an instruction manual and check it out.

 

[Bendts]

Also check to see that your ground glass in in the right way - right side up. Never tried to put one in the wrong way, but had this happen on an older 35mm, and it really hosed the focus.

Personally i find the RZ very easy to focus, esp compaired to a Hasselblad.

 

[dougjgreen]

I may have figured it out. I had been using a 220 insert in a 120 back. It seems to me that the back itself should be able to take any insert, however a few folks her on APUG have said that the back must match the insert. I will have to dig up an instruction manual and check it out.

This is not correct. The only thing that makes an RZ back into a 120 or 220 back is what insert is used.

Lifted directly from the Mamiya RZ instruction manual:

"The Roll Film Holder Housing will accept either 120 (HA703) or 220 (HB702) Film
Inserts"

 

[2F/2F]

This is not correct. The only thing that makes an RZ back into a 120 or 220 back is what insert is used.

Lifted directly from the Mamiya RZ instruction manual:

"The Roll Film Holder Housing will accept either 120 (HA703) or 220 (HB702) Film
Inserts"

Thanks. I had read that since my last post.

 

[ic-racer]

and it always ends up being focused on something closer to me than I want in focus.

The when the film bulges in the middle it is always TOWARD the lens (it can't bulge backward into the pressure plate) and that shifts the focus BEHIND your subject. So, based on what you are telling us, it does not seem like a film flatness issue.