Prontor Porfessional 3 operations

[Guglielmo]

Hi,

just purchased a Schneider 5,6/240 mm Apo-Symmar-S multicoating on Technika board for my Linhof Master Technika.
The fitted shutter is the Prontor Professional 3 whose operation seems smooth and reliable but I cannot understand how keep the shutter in "open" position for ground glass focusing.
Normally there is a lever to engage in open position the shutter while here there are 2 cable release interfaces...

Please let me know how to operate with this Prontor shutter, thank you so much, I appreciate your help!

Guglielmo

[David Lindquist]

I don't have any personal experience with these shutters, but this might help: https://skgrimes.com/products/shutters/prontor-shutters/

David

[Bob Salomon]

Hi,

just purchased a Schneider 5,6/240 mm Apo-Symmar-S multicoating on Technika board for my Linhof Master Technika.
The fitted shutter is the Prontor Professional 3 whose operation seems smooth and reliable but I cannot understand how keep the shutter in "open" position for ground glass focusing.
Normally there is a lever to engage in open position the shutter while here there are 2 cable release interfaces...

Please let me know how to operate with this Prontor shutter, thank you so much, I appreciate your help!

Guglielmo
You need two releases or the Prontor Profeessional Remote Control

[Guglielmo]

David, Bob,

thank you so much for kind clarification. Now it's clear that I need a double cable for shutter release and opening functions. I've to look for this item...

[Vaughan]

For viewing set the shutter to bulb and use a locking cable release.

I have a "for Wista" Copal Press shutter which is similar: it has a lever to open the shutter for viewing but it always opens the aperture. To view at the taking aperture it needs to be used on Bulb.

[David Lindquist]

David, Bob,

thank you so much for kind clarification. Now it's clear that I need a double cable for shutter release and opening functions. I've to look for this item...

You are very welcome, I'm glad this was helpful.

David

[Emmanuel BIGLER]

Hello from France, and congratulations for the purchase of a lens equipped with a Prontor Professional shutter.

In my opinion, this is the most beautiful mechanical shutter for large format lenses ever made.
As mentioned by Bob Salomon, you need two cable releases.
The first one, any kind, but preferably lockable, is to be screwed on the "white" thread: it will be used for the pre-selection of the aperture.
A light press on this "white" shutter release sets the aperture to the working aperture, which is supposed to help you see the depth of field, but if the working aperture is f/22, you can't see much anyway; a full press on the said "white" shutter release opens the aperture fully for composing and focusing.
The second cable release is to be screwed onto the "red" thread, it needs to be a very strong model and have a long travel in order to operate the self-cocking shutter properly.

The Prontor Professional is self-cocking, i.e. when the cable release on the "red" thread is pressed, the main shutter spring is first tensioned before the shutter is released.
A lever is used to activate (cock / release) the shutter in parallel with the cable release screwed on the "red" thread. So in practice, only one cable release is absolutely necessary, the one that screws on the "white thread" and opens the shutter to frame and focus.
So in order to tension and release the shutter, you can alternatively use the lever on the shutter itself.


With the Prontor Professional shutter, the working sequence is as follows:
- 1 - Prepare a loaded film holder;
- 2 - Press the shutter release (white) all the way down, the shutter opens, the aperture is set to the maximum opening;
- 3 - Compose and focus at full aperture, then release the "white" cable release to close the shutter;
- 4 - Set the shutter speed and aperture according to the chosen exposure;
- 5 - Important routine check, a glance at the front of the lens, to make sure that the shutter is closed; if it is not, release the "white" cable and see the shutter close:
- 6 - Insert the film holder;
- 7 - Remove the film holder dark slide;
- 8 - Fully press the main cable release (red):
- 9 - Re-insert the dark slide.

[Guglielmo]

Hello Emmanuel,

I greatly appreciate your detailed description about Prontor Pro operation sequence. Now it's definitely clear to me all the steps for shooting with this specific shutter whose characteristics are quite different from classic models which own. Once the practice is understood it become a smart modern shutter very helpful for composing pictures without worry. I will gladly learn your useful sequence of 9 steps!

Many thanks again for kind technical support!

Guglielmo frrom Italy