Mamiya RB67 mirror not dropping all the way

Hello,

I recently purchased a Mamiya RB67, it's my first medium format camera.

I haven't loaded with film yet as I want to figure out how to shoot the camera first before doing so.

When I take a "photo" and go to cock the shutter the mirror sometimes doesn't drop fully. I've taken the back off to have a look and it only partially drops down every second shot. If I press the shutter release and cock the mirror again it will then drop down completely. I've attached two photos.

Has anyone else had this problem/ does anyone know how to fix a faulty mirror or have any tips it would be really appreciated.

Thanks

That's not the mirror, it's the blind. You should read the instruction manual (easily available on the internet) carefully as the RB67 is not a straightforward camera to operate, there are a half dozen of interlinks, locks and safeties all of which have to be carefully considered.

Once you're absolutely persuaded that you're operating it correctly, I suggest you return the camera immediately without tampering it, and purchase another tested and in 100% working order. A faulty camera is not a good first step into medium format.

Okay thank you for your suggestion, I'll have a look into the manual further. Thanks

It could be the mirror is in the lockup position. This is due to the knob on the lens that controls it. There are two positions. N= normal when the mirror qon't lock up. M= when it locks up when you press the release button on the bottom right. But afterwards, you have to release the shutter with that know or cable release to release the shutter then close the mirror.

What position is the knob in?

@Alan Edward Klein Neither of those affects what happens when you cock the body, nor do they have any effect with the lens dismounted. And you can still recock everything after prefiring the mirror -- you'll just forego actually firing the shutter in that case. Depending on the body and back in use, this might require using the Double Exposure lever to make an actual image on the same film frame, but otherwise won't affect normal operation.

As Donald says, the mirror lock-up function on the lens doesn't affect the mirror, it just stops the shutter (which is in the lens) from opening when you push the release button on the camera.

MattKing said:

As Donald says, the mirror lock-up function on the lens doesn't affect the mirror, it just stops the shutter (which is in the lens) from opening when you push the release button on the camera.

Click to expand...

The mirror snaps and locks up when you press the release button on the camera. That's why it's called mirror lock-up. Then when you release the shutter on the lens, the shutter fires in the lens and the mirror releases afterwards returning itself to the normal down position.

Alan Edward Klein said:

The mirror snaps and locks up when you press the release button on the camera. That's why it's called mirror lock-up. Then when you release the shutter on the lens, the shutter fires in the lens and the mirror releases afterwards returning itself to the normal down position.

Click to expand...

On the RB67, the mirror stays up until you move it down again by cocking the camera with the lever on the side.

MattKing said:

On the RB67, the mirror stays up until you move it down again by cocking the camera with the lever on the side.

Click to expand...

You're right; good point. The knob locks the mirror and it or its cable release if connected only releases the shutter.

Alan Edward Klein said:

The knob locks the mirror and it or its cable release if connected only releases the shutter.

Click to expand...

Actually...
The way the RB67 works is that the shutter release on the body releases the cocked mirror, which flips up. The shutter release also causes an actuating lever on the lens to move.
When the mirror up control (not mirror lockup control) on the lens is in normal position, that actuating lever moves the lever in the lens that releases the in-lens shutter.
If however, you switch the mirror up control to engaged, you disconnect the actuating lever from the lever that releases the in-lens shutter. In essence, nothing happens with the shutter release when you push the release on the camera - they are no longer connected to each other, and they remain unconnected until you switch the mirror up control back. In order to actually release the shutter, you need to use the separate cable release you have screwed in to the connection provided as part of the mirror up system.
If you are not careful it is easy to forget to dis-engage the mirror up system and end up wasting the entire rest of the film (or even subsequent films) by trying to take photos without actually releasing the in-lens shutter.
The mirror up control has no effect on the shutter cocking function that also happens when you push the lever on the side of the camera - that connection is not interrupted by engaging he mirror up control.
There really is nothing that cocks the mirror up, other than not pushing the lever on the side of the camera.
All of which leads to the conclusion that the OP's problem probably has nothing to do with anything on the lens.
One thing I would suggest to the OP - check to make sure that there is nothing physical (like a strap) impeding full travel of the camera cocking lever.

MattKing said:

One thing I would suggest to the OP - check to make sure that there is nothing physical (like a strap) impeding full travel of the camera cocking lever.

Click to expand...

Bingo. Partial cocking would look like exactly that -- though I wouldn't expect to be able to operate the body release when halfway cocked.