Mamiya RB67 ProSD, darkslide block doesn't block

Joachim Zettl · Aug 10, 2014

Hi there, I am new to medium Format and have just bought myself for almost no money a used Mamiya RB67 ProSD. During shooting the first film I forgot to pull out the blind slide one time but I was still able to release the shutter and mirror and to advance the film afterwards. I thought there is a block which prevents this to happen. The back is 6x4.5 ProSD. Is that a problem of the back or of the body (or is it me )?

Xmas · Aug 10, 2014

The block is only applied if the dark slide is pushed in the final 3mm, you can shoot blank frames if the slide is out 3mm. There are two little triangles to indicate the slide is in the shoot blanks position.

Or there is a fault with the back.

You need to down load the manual. free!

Joachim Zettl · Aug 10, 2014

Thanks for the comment.

I just tried it again. It doesn't make a difference if the triangle is out or the slide ist completely in. The shutter is never blocked. So it is probably a technical problem with the back. I just realised how the pins on the darkslide push in two pieces of metal and make it possible to take off the back or lock it. This bit works, but it doesn't lock the shutter if the slide is pulled out.

Guess I have to try it with other backs to find out if the problem ist with teh back or the rotating part or the body. The postman will bring me a 6x7 back next week. Let's see.

Xmas · Aug 10, 2014

Sorry...

When you push the dark slide in to conceal the little triangle the tongue that pokes out to block the cameras 'im going to shoot' pin should poke out to physically block the shutter button pin and the shutter button.

But the back needs to be wound on ready to fire as well.

The tongue is the double exposure interlock as well as dark slide in... If you set the double exposure allowed on the back things are different I think...

If it don't it is the back.

But Im doing this from memory...

Vonder · Aug 10, 2014

The point of the dark slide is to let you change backs, and thus, film, whenever you want. There is no good reason to leave them in when shooting - unless you want to shoot blank frames. The lock mechanism isn't foolproof and yes, if you are determined enough, you can shoot with the dark slide in. Been there, done that, chucked the whole roll of film in the trash.

Xmas · Aug 10, 2014

Wolfeye said:
The point of the dark slide is to let you change backs, and thus, film, whenever you want. There is no good reason to leave them in when shooting - unless you want to shoot blank frames. The lock mechanism isn't foolproof and yes, if you are determined enough, you can shoot with the dark slide in. Been there, done that, chucked the whole roll of film in the trash.

If you have a proSD the interlock should be 100%?

jadphoto · Aug 10, 2014

Is the magazine set to multiple exposure? Little lever by the film advance lever. Red dot showing is to allow multiple exposures and I think it will disable the interlock.

JD

Joachim Zettl · Aug 10, 2014

jadphoto said:
Is the magazine set to multiple exposure? Little lever by the film advance lever. Red dot showing is to allow multiple exposures and I think it will disable the interlock.

JD

Nope - red dot is not showing. But thanks, now I know what the lever is for.

Xmas · Aug 10, 2014

When you fire the shutter you should see the little pin from the body poke into the hole in the back.

The back should throw the tongue out to stop a double exposure.

The tongue should withdraw when you wind the back.

If the back is an earlier back it may be missing interlocks it will still work ok.

But you need the user manual for the camera as relying in hints from web not going to work.

google Mamiya RB pro user manual

Joachim Zettl · Aug 10, 2014

Xmas said:
When you fire the shutter you should see the little pin from the body poke into the hole in the back.

That might be the problem. I can see a little pin in a hole moving when firing but it is not standing out and not poking in the hole of the back.

Xmas · Aug 10, 2014

Id need to have my RB to hand won't be near it till mid week.

It might work ok if you rotate the back.

mopar_guy · Aug 10, 2014

You might have a dark slide from a different kind of back.

Joachim Zettl · Aug 11, 2014

mopar_guy said:
You might have a dark slide from a different kind of back.

That could be, I will check when I get the 6x7 back this week.

DannL. · Aug 11, 2014

If your RB back operates anything like my RZ, you may find that installing the darkside only when it is needed "may" save your some grief one day. When I first bought my RZ, I was removing and installing the darkside each time I used the camera. One day I picked up the camera and the back fell off the camera. Luckily I caught it on the way down. The cause . . . The latch on the bottom of the film back wiggled over time to the unlocked position. With the darkside installed, there was nothing to hold the back onto the camera.

Joachim Zettl · Aug 13, 2014

The previous owner said that in his opinion the RB ProSD has no darkslide lock at all. I didn't check with the manual yet but I will.

MattKing · Aug 13, 2014

Joachim Zettl said:
The previous owner said that in his opinion the RB ProSD has no darkslide lock at all. I didn't check with the manual yet but I will.

Not sure what you mean by this.

If you mean that the dark slide can be pulled out at any time, that is wrong - the back must be on the camera, or the little pin must be manually pressed.

If you mean that the shutter can be released even if the dark slide is in, the manual says:

"The shutter release button can not be
depressed if the dark slide is completely
inserted or if here is no film in the camera.
In addition the Pro-SD roll film coupler prevents
multiple exposures. (See pages 16
and 25 for the shutter release test.)"

It may be the case that if you have a dark slide from an earlier version of the camera (RB67 Pro or Pro-S) that the dark slide exposure prevention interlock won't function. IIRC, that is what happens on my Pro-S when I insert a Pro dark slide.

mopar_guy · Aug 13, 2014

Matt, You can press the shutter release button on the camera body, but the interlock prevents the shutter in the lens from firing.

Joachim Zettl · Aug 14, 2014

I thought I can make it clearer when i show pictures.

A is the hole in the body where I can see a pin moving when pressing the shutter. The pin doesn't stick out when firing.
B shows the little hole in the rotating part which matches with the hole A on the body.
C is the little piece which moves when pushing in the dark slide completely
D is the part of the dark slide which speakes to the whole locking mechanism.

Since A never sticks out there is no connection between the locking mechanism of the darkslide/rotating part/back and the body.
I think A is meant to stick out to make it possible that the shutter is locked when the darkslide is fully in.

Hope it makes sense.

mopar_guy · Aug 14, 2014

There should be a pin where you have labeled "B" and it is not there.

Xmas · Aug 15, 2014

Can't see the photos on my phone but

On my 'pro S'

With back removed looking from rear of camera towards the lens with rotating adapter in landscape there are two chrome knobs

The right hand one is the shutter firing pin which is blocked by a back when the back is not able to fire this inhibits the shutter button depressing.

The left hand one tells the back that the mirror has finished its travel. Don't block it it is an instantaneous out and in you can just see it travel if you are careful. This pin tells the back to block the shutter release from depressing again until the back is wound on.

The dark slide overrides the logic.

An earlier camera, rotating adapter or back won't have all the logic they are still usable...

Joachim Zettl · Aug 15, 2014

mopar_guy said:
There should be a pin where you have labeled "B" and it is not there.

Thank you very much! That is it. This pin makes the connection to the body and prevents from firing when the darkslide is completely in.
Thank you all for your help!!!

paul ron · Aug 15, 2014

Also see if your darkslide has a notch? The older rb67 didnt have interlocks so using that will overide the mechanism.

Joachim Zettl · Aug 20, 2014

A nice guy at Mamiya in Germany sends me the pin, so I hope I will be able to build it into the adapter.
That would be good news!

WET-photo · Aug 25, 2014

Hey there, I had a similar problem with my RZ67 and wrote a repair guide. I don't know if it will help you with your RB67 but maybe you can apply one or two of the steps: Mamiya RZ67 Darkslide Repair Guide | wet-photo.at

Best regards,
Markus

Joachim Zettl · Aug 25, 2014

Thank you very much!
The RB does work a bit differently since it has no electronics at all and the rotating adapter ist not integrated in the body as it looks like on the RZ (at least a one part). Thanks anyway.

In case I have trouble mounting the pin, I will come back and ask.

Mamiya RB67 ProSD, darkslide block doesn't block

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