RB67 Lens Question

dbonamo · Jul 25, 2008

Hi

I have 2 questions maybe someone can answer.

When not using the lens should the shutter be cocked or not?

2nd question

This concerns the 180MM F4.5 Sekor C for the RB. I never notice but the shutter and aperture are behind the rear element on the lens I have. Is this normal for this lens? My other lens have the shutter/aperture between the front and rear elements, in other words protected within the lens.

Thanks

m_allard · Jul 25, 2008

When not using the lens should the shutter be cocked or not?

I leave mine cocked because i use them frequently. I think they should not be cocked for long term storage. You should probably also exercise these mechanical lenses periodically.

nemo999 · Jul 25, 2008

dbonamo said:
Hi

I have 2 questions maybe someone can answer.

When not using the lens should the shutter be cocked or not?

2nd question

This concerns the 180MM F4.5 Sekor C for the RB. I never notice but the shutter and aperture are behind the rear element on the lens I have. Is this normal for this lens? My other lens have the shutter/aperture between the front and rear elements, in other words protected within the lens.

Thanks

It must have been Mamiya's intention that shutters should be left cocked, since you cannot remove a lens from the body unless this is done. I have never noticed any disadvantage from leaving the shutters cocked.

Answer to second question - yes, it is normal. Unusual, but normal for this lens.

max_ebb · Jul 25, 2008

nemo999 said:
It must have been Mamiya's intention that shutters should be left cocked, since you cannot remove a lens from the body unless this is done.

According to Mamiya, the shutter should be un-cocked for long term storage. The reason that the lens has to be cocked before removing it from the body is that the mirror is up if the shutter isn't cocked, and if you didn't have a dark slide in and removed the lens with the mirror up you would expose the film to light. It's easy enough to cock/un-cock the lens with it off the camera.

ccd · Jul 28, 2008

I just received an RB67 that I got off *bay and was putting it thru it's paces and I've run into some problems. One of my questions is about the the lens . . .it's a 90mm lens and the manual says to (with the lens off) cock the shutter by moving the pins to the red dots, are the pins supposed to stay at the red dots?? I moved them to the red dots but they don't stay there and I didn't hear anything move. Can you help?? Sorry about hijacking this post, I'm frustrated.

Gatsby1923 · Jul 28, 2008

They don;t stay their so fear not. they move a little bit after you cock them.

ccd · Jul 29, 2008

Thank you! I thought I was going crazy!

Don Wallace · Jul 29, 2008

On a related note, I used the "mirror up" setting on the lens a while ago, for the first time ever, and forgot to take it off that setting when I removed that lens (the 180mm). A few months later, I pulled out the 180 for a roll of portraits. The roll was entirely blank of course. Live and learn

paul ron · Aug 1, 2008

The 180mm lens doesn't have a rear cell as the rest of the lenses do. So this is normal for it to have the shutter n iris blades exposed.

A shutter that is being stored for long periods of time should be left uncocked, put in a plastic zip lock with a silica packet to reduce the moisture so fungus will not eat it up.

My recomendation is to excercise the shutters every week by running it through the speeds a few times just to keep the brass parts self lubicating n the slight bit of grease on the rub parts fluid. You can sotre em for months at a time with out doing this but you will run the risk of it being slugish when you need it most.

RB67 Lens Question

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