What is a Press Shutters

[Absinthe]

I have been looking at a lot of stuff about shutters lately. However, what I can't find is what the term "Press" means specifically when something is a "Press Shutter"

 

[AgX]

I it is a shutter which is cocked whilst pushing the release knob. (Due to higher `release´ forces preferably with a release cable.)

By this you spare one maneuvre, thus you are faster.

Another term would be `self-cocking´.

 

[Uhner]

Yes, it is a self-cocking shutter for large format lenses.

 

[Trevor Crone]

These are my prefered shutter, particularly the Copal Press (sadly no longer manufactured). They allow easy multiple exposures without having to touch the camera between exposures. They are also faster in use, by not having to cock the shutter plus they allow the lens to be kept in the stopped down position.

They were originally found on 'Press' cameras because of their faster use.

 

[DJGainer]

I was looking at them too, as I am new to large format. Are there drawbacks to press shutters?

 

[Trevor Crone]

I was looking at them too, as I am new to large format. Are there drawbacks to press shutters?

Top speeds tend to be about 1/125, at least this is my experience with the Copal Press.

 

[David A. Goldfarb]

I like press shutters, but some are a bit larger than their standard counterparts. For instance a Copal 1 Press needs a larger mounting hole than a standard Copal 1, so it usually means having to have the lensboard hole machined specially, rather than using an off-the-shelf lensboard--which is not too unusual, if you use lenses in odd-sized shutters, but should be mentioned. Press shutters usually also have a slower top speed than their similarly-sized counterparts.

Press shutters may have a bit more vibration than standard shutters, since you cock the shutter and release it immediately, whereas with a regular shutter, any vibration from cocking the shutter will die down before firing the shutter. Whether this is significant depends on what you're doing. Shutters for high magnification work, for instance, are often press shutters, because this kind of photography is often done with strobes, and multiple pops are common, so the advantage of not having to re-cock the shutter and potentially move the lens outweighs the potential for vibration, which is insignificant with strobe exposure anyway. But if you were going to make a high magnification photograph with a single exposure of 1/15 sec (a very unlikely situation, because need for DOF plus bellows factor plus reciprocity usually necessitates long exposures or strobes), you might worry about vibration from a press shutter.

 

[removed account4]

they are also the shutters on polaroid copy cameras, usually outfitted with
tominon lenses. i have one that came with a tominon 127mm lens and love it.
i have read that they don't cover a 4x5 sheet, but i've been using mine
( came with my speed graphic ) with no problems since its purchase 20 years ago.
you might find press shutters by searching eBoo for polaroid-stuff and get them
for very little money, g-claron lenses fit right on them too

 

[Absinthe]

Thanks. I had assumed it had something to do with "press" cameras and I can see how being self cocking might be advantageous for a member of the press

 

[Absinthe]

I will have to google around but what is a g-claron lens? Is that a type or a brand?

 

[Uhner]

I will have to google around but what is a g-claron lens? Is that a type or a brand?

It is a type of repro lenses made by Schneider-Kreuznach

http://www.schneiderkreuznach.com/foto/gcn/gcn.htm

 

[Trevor Crone]

All the Copal Press shutters I have come across are self-cocking, the shutter does not need to be recocked between exposures, although it is good practice to trip shutters with a cable release to prevent vibrations.

I have a 240mm Tele-Congo lens in a No.1 Copal Press shutter and it is the same hole size as standard Copal No.1 shutters.

The other slight downside with the Copal Press is it dosn't have a T setting, just B, so for long continuous time exposures a lockable cable release is required.

The Compur Press shutter does however need recocking at settings other then B and T.

 

[Uhner]

Just to add a little more confusion. I have a Convertible Symmar mounted in a Copal-Polaroid Press shutter that has both a B and a T setting…

 

[John Kasaian]

I will have to google around but what is a g-claron lens? Is that a type or a brand?

It is one of the very best, IMHO. They only open to f/9 but are bright, sharp, lightwieght, smaller than plasmats, and have great coverage---they used to be dirt cheap but the cat is out of the bag and prices are going up! They'll also fit directly in either an ""0" "1" or "3" Copal or Prontor press or regular shutters (but not the wierder variants---so beware!)

 

[Absinthe]

Hmmm, the copal that I stole out of the Polaroid MP-4 has a T and B, I thought... Not you are making me think. Is it possible that it has a different shutter release that does the focus thing, and one for doing release thing. For some reason I am thinking it has 2 ports to connect cable releases to. I know that because someone broke one off in each one and I had to dig them out without gammying up the threads...

 

[David A. Goldfarb]

Hmmm... seems there are different versions of these shutters, because my Copal 1 Press is definitely larger than a standard Copal 1, though the current versions are the same.

Here is some info about Copal shutters--

http://www.skgrimes.com/products/index.htm

And Copal Press shutters--

http://www.skgrimes.com/press/index.htm

 

[Dan Fromm]

I like press shutters, but some are a bit larger than their standard counterparts. For instance a Copal 1 Press needs a larger mounting hole than a standard Copal 1, so it usually means having to have the lensboard hole machined specially, rather than using an off-the-shelf lensboard--which is not too unusual, if you use lenses in odd-sized shutters, but should be mentioned. Press shutters usually also have a slower top speed than their similarly-sized counterparts.

<snip>

David, www.skgrimes.com says that Copal #1 and #1 Press both want a 41.6 mm hole. Mine accept the same retaining ring, which also fits a SynchroCompur #1. I have a Copal #0 Press and a number of SynchroCompur #0s; both types accept the same retaining ring and go in the same sized hole.

There are differences between Press and cock-and-shoot shutters that can bite, though. If you visit the grimes site and look at their shutter specs you'll see that the Press shutter's diaphragm sits ~ 1 mm farther back than the cock-and-shoot shutter's.

This can cause problems with lenses whose rear cells go deep into the shutter. For example, I have a set of 80/2.8 Planar cells whose rear cell will hit a Copal #1 Press' and a Prontor #1 Press' diaphragms but that mounts correctly in a Compur and a Copal cock-and-shoot #1.

Grimes gives dimensions for Copal Press shutters. Prontor Press shutters aren't exactly the same. I have a 95/2.8 Saphir whose rear cell hits a Copal 1 Press' diaphragm but not a Prontor Press #1's.

IMO -- I think Jim Galli can add usefully here -- the only Polaroid Copal 1 Press that's relatively safe for general use is the one sold with a 127/4.7 Tominon mounted. I say relatively because the one I bought for that Planar won't do. Polaroid Copal shutters sold with shorter Tominons in them have (some, Jim, or all?) diaphragms whose maximum aperture is restricted. This can be limiting, depending on the lens fitted. The MP-4 Copal #1 Press has no diaphragm -- that's why they sell for so little used -- but are great for front-mounting.

Cheers,

Dan

 

[Trevor Crone]

I'm not surprised David I think a fair few versions have evolved over the years.

I think you'll find modern Copal Press shutters do not have a T setting. I have 4 modern Copal Press shutters and none of them have T. However my Compur Press has both B and T but this is a different shutter and is much older.

 

[Grafmatic]

This thread explains why there has been a 180 Nikkor sitting on ebay for awhile even though the glass appears flawless

 

[Marcelo Paniagua]

Let dead thread rest in peace