c330: shutter cocking do and dont

Thread view:

Enable EMail Alerts

Start New Thread

Thread rating:

redcat - 27 Jul 2003 16:58 GMT

Hi all,
once again, another question on the C330.
This is more of a workflow question. While shooting, I find myself
automatically readying for the next shot by advancing the film before
setting up my shot. This automatically cocks the shutter as well. Now, when
i begin composing for the next shot, i find that i might have to change the
shutter speed on the already-cocked shutter. I am not sure if this is a good
thing to do. The guy at KEH said its definitely not a good thing for the
shutter because its already cocked. The reason i ask this is because when i
change the shutter speed after it is cocked, i get a "scrapy" sound from the
shutter that i never get when i am adjusting shutter speed BEFORE advancing
the film.

But then again, with manual 35mm cameras, i could always change shutter
speed at any time before or after advancing the film. Is there a difference
here because the shutter is within the lens and not the body?

What do the wise men say to this?
redcat

Reply to this Message

dr bob - 28 Jul 2003 05:48 GMT

> Hi all,
> once again, another question on the C330.
[quoted text clipped - 15 lines]
> What do the wise men say to this?
> redcat

It is not the best practice to change shutter settings while it is
cocked but it won't be disastrous. The "scrapy" sound is the gears meshing
which occurs when the springs are compressed after cocking. It is abnormal
movement and it does create stress in the bearings in directions they would
not normally see. A change of one speed should have very little effect on
operation. I find I have to do this occasionally and so far there has been
no bad effects - that I know of. I would advise against
moving the speed ring from one extreme to the other however. One nice thing
about the Mamiya TLRs, parts are still available.

Truly, dr bob.

Reply to this Message

Mike - 28 Jul 2003 06:12 GMT

> > Hi all,
> > once again, another question on the C330.
[quoted text clipped - 34 lines]
>
> Truly, dr bob.

The sounds you hear when changing speeds on a cocked shutter, are the gears
of the speed governor and the pin of the segment gear pin the pin rubs along
the edge of the speed cam. The engagement of the pin will depend on which
speed you are on with one second giving the most and 1/500 the least.
You might also hear the shutter speed ring rubbing along parts of the
shutter housing.
On modern shutters you will do little damage to the governor unless your
changing speeds quickly, then you might do some damage as the governor is
not designed to cycle quickly.
Mike

Reply to this Message

Dan Quinn - 29 Jul 2003 03:52 GMT

RE: "Mike" <nedsnake@earthlink.net>

The matter of which you speak is of concern when SLR cameras with
coupled mirror and shutter are used. That concern surfaced while reading
the RB67 Pro S manual. The mirror return also cocks the shutter.
The RZ67, which has electronic shutter, proper B and T, and 1, 2,
4, and 8 second speeds, uses a body mount shutter speed dial. Ditto
for my ETRSi, and I'm quite sure a number of other electronic
shuttered cameras. Dan

Reply to this Message

Mike - 29 Jul 2003 04:14 GMT

> RE: "Mike" <nedsnake@earthlink.net>
>
[quoted text clipped - 5 lines]
> for my ETRSi, and I'm quite sure a number of other electronic
> shuttered cameras. Dan

The RZ Pro I, II and the entire current Bronica line, do not have mechincal
speed governors. With respect to the modern, 1960's forward, leaf shutters
in the entire Mamiya line or the Omega cameras; there is little chance that
you will damage the governor if you slowly rotate the speed ring with the
shutter cocked.

Reply to this Message

Winfried Buechsenschuetz - 28 Jul 2003 07:07 GMT

> But then again, with manual 35mm cameras, i could always change shutter
> speed at any time before or after advancing the film. Is there a difference
> here because the shutter is within the lens and not the body?
>
> What do the wise men say to this?

I am not sure if I am wise but listen to what I am saying:

All leaf shutters control the speed via an escapement gear. A lever
protruding from the escapement mechanism will delay the shutter
cocking shaft when turning. The base position of this lever is set via
the shutter cams and a control pin linked to this lever.

Once the shutter is released the control pin of the escapement gear
does no longer ride on the cams. Thus, if you move the dial now,
changing the cams will have no audible effect. The control pin only
rides on the cams when the shutter is cocked. What you hear is no
'scraping' sound but rather a buzzing sound since the gears are moved
a bit when the control pin goes from one cam to another one.

Usually, if the shutter is well designed and if the cam material is
hard enough (usually it is chrome plated brass) there will be no
noticeable wear if you move the shutter dial when the shutter is
cocked. Only exception are early Compur Rapid shutters, on these
shutters it is recommend NOT to set them to the fastest speed when the
shutter is cocked (these guys have a strong booster spring for highest
speed which puts a lot of pressure on the related cam).

Also, it makes no difference whether a leaf shutter is in a fixed lens
or in an interchangeable one.

Winfried

Reply to this Message

Graham Patterson - 28 Jul 2003 18:42 GMT

If you are really worried about changing speeds on a cocked
shutter, you can go through an elaborate process to avoid it:

Set the camera to 'Unlock' to close the film baffle.
Trip the shutter ON THE LENS (saves messing with the Multi
setting, but that is an option)
Reset the speed
Cock the shutter using the lens arm

I suspect most people just change the speed - I do. But don't
move it more than one step at a time. There are no cautions about
this in any of the Mamiya documentation I have read.

Graham

Reply to this Message