Mamiya RB67 Lens Issue

[aoresteen]

I just purchased an RB67 65mm f/4.5 lens, first version from the early 1970's. I've NEVER used an RB67 camera let alone an RB67 lens. I do not have an RB67 body - just the lens.

I bought a view camera lens board that has an RB67 lens mount on it and my plan is to use the 65mm lens on my Cambo 23SF 6x9 view camera.

http://www.ebay.com/itm/111810834091?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT

The Mamiya 65mm lens mounts just fine on the lens board and I can trip the lens shutter by pressing down on the silver lever.

When I set the M/N switch to M (mirror up mode) and trip the shutter with the silver lever, the lens stops down and waits for me to trip the shutter with a cable release in the M/N switch socket.

Here's my issue: The shutter blades never close before the shutter trips. When used in the M mode, the aperture is stopped down but the shutter blades are OPEN, letting light into the camera. I can't pull the dark-slide or the film will be exposed before I get a chance to use the cable release to trip the shutter.

I do not know if this is is normal behavior or not for a RB67 lens.

It seems to me that in mirror lock up mode the lens should stop down the aperture, close the shutter, and wait for the shutter to be tripped bay a cable release in the M/N socket. Why would it leave the shutter blades open, letting light into the camera?

1. How do I get the RB67 lens to stop down the aperture and close the shutter so that I can pull a dark slide and then trip the shutter with a cable release?

2. There is a 2nd cable release socket on the lens by the M/X switch and I can not figure out what it does.

This is NOT the M/N switch cable release socket. What is this 2nd cable release socket on the RB67 lens for?


The lens was purchased from a reputable dealer in Japan (I'm in the USA) and I planned on having the lens serviced as it's about 46 years old even though the seller said it's in working order.

Thanks for your help sorting this out!

 

[paul ron]

rb lenses only have one cable release socket. id be curious to see a photo of what you're describing?

try firing the lens off camera without the adaptor?

it is possable your lens needs service.

 

[MattKing]

I would think that the silver lever on the adapter is for cocking the shutter.

The cable release is for releasing the shutter.

 

[aoresteen]

rb lenses only have one cable release socket. id be curious to see a photo of what you're describing?

try firing the lens off camera without the adaptor?

it is possable your lens needs service.

Yes I did fire the lens off adapter. To fire an RB67 lens off the camera you depress a tiny pin and the push the side lever down. This triggers the shutter on the lens. Again when this happens the shutter blades never close - they just fire. And if I put it in mirror lock-up mode (M) the lens stops down and waits for the cable release to trip the shutter. While waiting, the lens is open with light streaming through it.

The photo shows the 2nd cable release socket by the M/X switch. The other one is in the M/N switch.

I would think that the silver lever on the adapter is for cocking the shutter.

The cable release is for releasing the shutter.

Not true. While the lever does cock the shutter it also fires it. For the cable release to fire the shutter the N/M switch has to be set to M first. Otherwise at the end of the lever travel the shutter fires (just like it would with the lens off camera & off the adapter).

 

[MattKing]

When the lens is on a camera, the normal sequence is straight-forward, if somewhat complex.

1) operating the wind lever on the camera lowers the mirror, cocks the shutter, opens the shutter and opens the aperture;
2) releasing the shutter release closes the shutter, stops the aperture down, lifts the mirror, then releases the shutter, which opens and then closes the shutter.

If you use the mirror lockup function, it changes it slightly, in that after the shutter closes it stays closed while the aperture stops down and the mirror lifts. The shutter stays in that closed position unless and until the cable release is pressed, at which time the shutter opens then closes.

The "resting" position of the cocked shutter is open.

I would think that the workflow would require you to view and focus with the shutter open, then engage the M (not N) setting, use the lever (which should cock and close the shutter) and then release the shutter using the cable release.

 

[aoresteen]

When the lens is on a camera, the normal sequence is straight-forward, if somewhat complex.

1) operating the wind lever on the camera lowers the mirror, cocks the shutter, opens the shutter and opens the aperture;
2) releasing the shutter release closes the shutter, stops the aperture down, lifts the mirror, then releases the shutter, which opens and then closes the shutter.

If you use the mirror lockup function, it changes it slightly, in that after the shutter closes it stays closed while the aperture stops down and the mirror lifts. The shutter stays in that closed position unless and until the cable release is pressed, at which time the shutter opens then closes.

The "resting" position of the cocked shutter is open.

I would think that the workflow would require you to view and focus with the shutter open, then engage the M (not N) setting, use the lever (which should cock and close the shutter) and then release the shutter using the cable release.

So if I trip the shutter with the lens off the camera, the first thing that happens is the shutter closes. Then the aperture stops down. Then the shutter trips at the set speed. To trip the shutter on an RB67 lens that is off the camera see this video:



The procedure is shown at 4 minutes 10 secs.

My lens the shutter never closes. It stops down, then trips the shutter. Can someone take an RB67 lens and watch it as it's tripped off camera and let me know if you see the shutter blades closing before stop down?

Thanks!

 

[MattKing]

On the lens closest at hand when I trip it off the camera "the first thing that happens is the shutter closes. Then the aperture stops down. Then the shutter trips at the set speed."

 

[Maris]

I have the view camera lens board adapter for Mamiya RB67 lenses and it works perfectly.
This is what I do:
Turn the RB lens shutter socket ring from N to M = mirror up.
Screw in a shutter cable release.
Place the RB lens on the adapter and secure it by turning the lens breech lock ring clockwise.
Push the silver lever of the adapter to the top. This cocks the shutter and opens the shutter and the iris of the lens for viewing.
Push the silver lever to the bottom. This closes the shutter and the iris and readies the lens for the exposure.
Press the shutter release. The shutter opens and closes for the shutter speed set on the lens.
Push the silver lever of the adapter to the top...and continue as described above.

If this is not what is happening for you I'd suspect a bad adapter or a bad lens.

 

[aoresteen]

I have the view camera lens board adapter for Mamiya RB67 lenses and it works perfectly.
This is what I do:
Turn the RB lens shutter socket ring from N to M = mirror up.
Screw in a shutter cable release.
Place the RB lens on the adapter and secure it by turning the lens breech lock ring clockwise.
Push the silver lever of the adapter to the top. This cocks the shutter and opens the shutter and the iris of the lens for viewing.
Push the silver lever to the bottom. This closes the shutter and the iris and readies the lens for the exposure.
Press the shutter release. The shutter opens and closes for the shutter speed set on the lens.
Push the silver lever of the adapter to the top...and continue as described above.

If this is not what is happening for you I'd suspect a bad adapter or a bad lens.

Marvis, many thanks. I agree that my lens is not working properly. I will have it serviced.

 

[paul ron]

if you tried it off camera n still doesnt close down, the lens needs service.

Yes I did fire the lens off adapter. To fire an RB67 lens off the camera you depress a tiny pin and the push the side lever down. This triggers the shutter on the lens. Again when this happens the shutter blades never close - they just fire. And if I put it in mirror lock-up mode (M) the lens stops down and waits for the cable release to trip the shutter. While waiting, the lens is open with light streaming through it.

The photo shows the 2nd cable release socket by the M/X switch. The other one is in the M/N switch.




Not true. While the lever does cock the shutter it also fires it. For the cable release to fire the shutter the N/M switch has to be set to M first. Otherwise at the end of the lever travel the shutter fires (just like it would with the lens off camera & off the adapter).

 

[aoresteen]

if you tried it off camera n still doesnt close down, the lens needs service.

Thanks. I've reached that conclusion and will send the lens in for a CLA service.

 

[aoresteen]

UPDATE: I had the lens serviced last year by Forest Camera Repair in Hendersonville TN and it now functions correctly.

SK Grimes mounted the RB lens adapter on a Cambo SF69 lensboard and now everything works correctly.