How does shutter timing work?

[denalilap]

New here and about to purchase my first 4x5. In looking for lenses it got me wondering how the timing mechanism in shutters work? Is there some type of spring that controls the timing?

[Mark Sawyer]

Yes, and on most shutters it can be easily damaged by someone not knowing what they're doing abusing the shutter, or simply long-term improper storage. Used shutters are like used cars, newer is more reliable, but it depends on how it was driven.

Like most of the world, large format photography is a nightmare... :rolleyes:

[Leigh]

Like most of the world, large format photography is a nightmare... :rolleyes:No. It's more of a daymare.

It doesn't work very well at night. :p

To answer the OP's question...
Shutter timing is accomplished using springs and gears, exactly like a mechanical watch or clock.

- Leigh

[LabRat]

In a standard leaf shutter there are 2 sections inside... The higher speeds have a spring pushing the blades open and closed... But there is something that creates a larger or smaller gap between the open/closing blades that allow faster/slower time open depending on the size of that gap... (It's a little like snapping your fingers... It happens fast, but if you had longer fingers (a bigger gap space) your thumb would travel further and you snap would last a little longer... I hope this helps explain...)

Under a certain speed, open/closed blades need more of a delay, so there are a set of gears that spin fast but the last gear slowly moves a lever that slowly allows the shutter to close (you can hear it's gears buzzing when operating)... So a mechanical delay that kicks in...

Then there's the iris in there, and different flat arms inside that allow the shutter to just open for time exposures, and preview (focusing)... And some electrical contacts that meet when the shutter is at a wide open point to fire your flash...

And all in a small package under and around your lens...

Just don't ask me how anyone figured out how to do this, it is quite amazing... ;-)

Steve K

[pepeguitarra]

Having bought about 10 used lenses, I had to have CLA done to eight of them, I can tell you that whenever you hear the words "speeds sound good to me", don't buy it, or buy it, but add $100 per shutter for CLA to the price. I also bought a brand new in the box Kodak Supermatic shutter, indeed, it was never used. Well, it was so hard to change speed that it had to be sent for CLA too. You need to use them, otherwise, the grease or lubricant will solidify (I guess) and get stuck. So, one weekend of the month, I sit down with all of them and shoot them "to the air".

[Jim Jones]

The slowest timing in modern shutters for large format is controlled by a spring driven series of gears that ultimately drive a rocker that acts like a pendulum on steroids. For the intermediate speeds the rocker is disengaged, and the gear train can run down faster. A booster spring speeds up the fastest shutter speed. The simple old Compound (and many other) shutters use an air piston to control the time the shutter blades are open.

[Tin Can]

There are other shutters.

Some here use a hat, not kidding!

I like Packard Shutters which are very simple in construction and work well for decades.

Their 120 year history is interesting. The company just changed ownership and still makes them.

The new company. https://packardshutter.com/

The fanclub. http://www.mikeeckman.com/2018/03/introducing-the-packard-ideal-shutter-company/

I used one last night to shoot these pics posted here. https://www.largeformatphotography.info/forum/showthread.php?149304-Kang-Rinpoche-S-600-F11-5-(Chinese-Fujinon-C-600mm-)&p=1477771&viewfull=1#post1477771

[denalilap]

Having bought about 10 used lenses, I had to have CLA done to eight of them, I can tell you that whenever you hear the words "speeds sound good to me", don't buy it, or buy it, but add $100 per shutter for CLA to the price. I also bought a brand new in the box Kodak Supermatic shutter, indeed, it was never used. Well, it was so hard to change speed that it had to be sent for CLA too. You need to use them, otherwise, the grease or lubricant will solidify (I guess) and get stuck. So, one weekend of the month, I sit down with all of them and shoot them "to the air".

What is CLA and where does one have it done?

[Larry Gebhardt]

What is CLA and where does one have it done?

Clean, lube and adjust. I've had good luck with skgrimes.com

[Leigh]

What is CLA and where does one have it done?
We need to know where you are.
You might put that in your Profile so it shows up on every post.

There are good service shops all over the country.

- Leigh

[bgh]

Clean, lube and adjust. I've had good luck with skgrimes.com

Alas, I contacted S.K. Grimes a month ago about sending a lens for CLA; I was told that their technician had passed away last fall, and they are no longer servicing shutters. They suggested Carol Flutot.

Bruce

[David Lindquist]

Alas, I contacted S.K. Grimes a month ago about sending a lens for CLA; I was told that their technician had passed away last fall, and they are no longer servicing shutters. They suggested Carol Flutot.

Bruce

I'm very sorry to hear that, thank you for letting us know. I'm guessing it was Joel (didn't know his last name). Think I talked to him once or twice on the phone, seemed like a nice guy as well as being skilled in his craft.

Just looked at their website, they just say that as of Oct. 5, 2018 they no longer do CLA's.
David

[Tin Can]

Shutter repair will become an ongoing problem as few can or will do it.

I know I cannot, maybe 50 years ago when my fingers were nimble and my eyes clear.

Also doubt new shutters will be made, how long will Packard keep at it?

There are other ways. The Jim Galli shutter (https://www.photrio.com/forum/threads/the-jim-galli-shutter-for-barrel-lenses-drum-roll-please.13953/) is unique and easy for some, not me.

Treasure and exercise your 'good' shutters.